From cd5a08ba607875b4e6e98f5f40e6e11d1b4aa615 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Wed, 1 Oct 2025 14:53:08 +0200
Subject: [PATCH 01/25] gen ssl key pair and convert the public key to JWK

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 appinfo/routes.php               |  1 +
 composer.json                    |  3 +-
 composer.lock                    | 56 ++++++++++++++++++++++++++++++-
 lib/Controller/ApiController.php | 14 ++++++++
 lib/Service/JwkService.php       | 57 ++++++++++++++++++++++++++++++++
 5 files changed, 129 insertions(+), 2 deletions(-)
 create mode 100644 lib/Service/JwkService.php

diff --git a/appinfo/routes.php b/appinfo/routes.php
index ad005f87..05584c8e 100644
--- a/appinfo/routes.php
+++ b/appinfo/routes.php
@@ -19,6 +19,7 @@
 
 		['name' => 'api#createUser', 'url' => '/user', 'verb' => 'POST'],
 		['name' => 'api#deleteUser', 'url' => '/user/{userId}', 'verb' => 'DELETE'],
+		['name' => 'api#getJwks', 'url' => '/jwks', 'verb' => 'GET'],
 
 		['name' => 'id4me#showLogin', 'url' => '/id4me', 'verb' => 'GET'],
 		['name' => 'id4me#login', 'url' => '/id4me', 'verb' => 'POST'],
diff --git a/composer.json b/composer.json
index 49b50b80..287c3905 100644
--- a/composer.json
+++ b/composer.json
@@ -32,7 +32,8 @@
   "require": {
     "id4me/id4me-rp": "^1.2",
     "firebase/php-jwt": "^7",
-    "bamarni/composer-bin-plugin": "^1.4"
+    "bamarni/composer-bin-plugin": "^1.4",
+    "strobotti/php-jwk": "^1.3"
   },
   "require-dev": {
     "nextcloud/coding-standard": "^1.0.0",
diff --git a/composer.lock b/composer.lock
index a03c9589..a1dc04f1 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "d04dc4373433d9ac88a4fd120a014533",
+    "content-hash": "2c4f937df9960ebd989efe94d706e93b",
     "packages": [
         {
             "name": "bamarni/composer-bin-plugin",
@@ -280,6 +280,60 @@
                 }
             ],
             "time": "2026-03-19T02:54:44+00:00"
+        },
+        {
+            "name": "strobotti/php-jwk",
+            "version": "v1.3.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/Strobotti/php-jwk.git",
+                "reference": "a78580b55380f25bd8110452a5a031e36043551e"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/Strobotti/php-jwk/zipball/a78580b55380f25bd8110452a5a031e36043551e",
+                "reference": "a78580b55380f25bd8110452a5a031e36043551e",
+                "shasum": ""
+            },
+            "require": {
+                "ext-json": "*",
+                "ext-openssl": "*",
+                "php": ">=7.2.0",
+                "phpseclib/phpseclib": "^2.0"
+            },
+            "require-dev": {
+                "friendsofphp/php-cs-fixer": "^2.16",
+                "phpunit/phpunit": "^8.0"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Strobotti\\JWK\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Juha Jantunen",
+                    "email": "juha@strobotti.com",
+                    "homepage": "https://www.strobotti.com",
+                    "role": "Developer"
+                }
+            ],
+            "description": "A small PHP library to handle JWKs (Json Web Keys)",
+            "homepage": "https://github.com/Strobotti/php-jwk",
+            "keywords": [
+                "JWK",
+                "JWKS"
+            ],
+            "support": {
+                "issues": "https://github.com/Strobotti/php-jwk/issues",
+                "source": "https://github.com/Strobotti/php-jwk/tree/master"
+            },
+            "time": "2020-04-01T03:22:04+00:00"
         }
     ],
     "packages-dev": [
diff --git a/lib/Controller/ApiController.php b/lib/Controller/ApiController.php
index 28aaa6c7..53750d08 100644
--- a/lib/Controller/ApiController.php
+++ b/lib/Controller/ApiController.php
@@ -11,10 +11,12 @@
 
 use OCA\UserOIDC\AppInfo\Application;
 use OCA\UserOIDC\Db\UserMapper;
+use OCA\UserOIDC\Service\JwkService;
 use OCP\AppFramework\Controller;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\Attribute\NoCSRFRequired;
 use OCP\AppFramework\Http\Attribute\OpenAPI;
+use OCP\AppFramework\Http\Attribute\PublicPage;
 use OCP\AppFramework\Http\DataResponse;
 use OCP\Files\IRootFolder;
 use OCP\Files\NotPermittedException;
@@ -29,6 +31,7 @@ public function __construct(
 		private IRootFolder $root,
 		private UserMapper $userMapper,
 		private IUserManager $userManager,
+		private JwkService $jwkService,
 	) {
 		parent::__construct(Application::APP_ID, $request);
 	}
@@ -82,4 +85,15 @@ public function deleteUser(string $userId): DataResponse {
 		$user->delete();
 		return new DataResponse(['user_id' => $userId], Http::STATUS_OK);
 	}
+
+	#[NoCSRFRequired]
+	#[PublicPage]
+	public function getJwks(): DataResponse {
+		$jwks = $this->jwkService->getJwks();
+		return new DataResponse([
+			'keys' => [
+				$jwks['public'],
+			],
+		]);
+	}
 }
diff --git a/lib/Service/JwkService.php b/lib/Service/JwkService.php
new file mode 100644
index 00000000..877e8ecc
--- /dev/null
+++ b/lib/Service/JwkService.php
@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\UserOIDC\Service;
+
+require_once __DIR__ . '/../../vendor/autoload.php';
+
+use Strobotti\JWK\KeyFactory;
+
+class JwkService {
+
+	public function __construct(
+	) {
+
+	}
+
+	public function getJwks(): array {
+		$keyPair = $this->createKeyPair();
+
+		$options = [
+			'use' => 'sig',
+			'alg' => 'sha512',
+			'kid' => 'plop',
+		];
+		$keyFactory = new KeyFactory();
+		$publicJwk = $keyFactory->createFromPem($keyPair['public'], $options);
+		// $privateJwk = $keyFactory->createFromPem($keyPair['private'], $options);
+		return [
+			'public' => $publicJwk,
+			//'private' => $privateJwk,
+		];
+	}
+
+	public function createKeyPair(): array {
+		$config = [
+			'digest_alg' => 'sha512',
+			'private_key_bits' => 4096,
+			'private_key_type' => OPENSSL_KEYTYPE_RSA,
+		];
+
+		// Create the private and public key
+		$key = openssl_pkey_new($config);
+		openssl_pkey_export($key, $privKeyPem);
+		$pubKey = openssl_pkey_get_details($key);
+		$pubKeyPem = $pubKey['key'];
+
+		return [
+			'public' => $pubKeyPem,
+			'private' => $privKeyPem,
+		];
+	}
+}

From 18bbc9a8161622e3b15598d45e1e47e31d2c52d6 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Thu, 9 Oct 2025 10:02:35 +0200
Subject: [PATCH 02/25] store pem priv key in appconfig, gen JWK from public
 ssl key, test creating and decoding JWT from our key

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 lib/Controller/ApiController.php |  16 ++--
 lib/Service/JwkService.php       | 125 ++++++++++++++++++++++++++-----
 2 files changed, 115 insertions(+), 26 deletions(-)

diff --git a/lib/Controller/ApiController.php b/lib/Controller/ApiController.php
index 53750d08..9d777c32 100644
--- a/lib/Controller/ApiController.php
+++ b/lib/Controller/ApiController.php
@@ -18,6 +18,7 @@
 use OCP\AppFramework\Http\Attribute\OpenAPI;
 use OCP\AppFramework\Http\Attribute\PublicPage;
 use OCP\AppFramework\Http\DataResponse;
+use OCP\AppFramework\Http\JSONResponse;
 use OCP\Files\IRootFolder;
 use OCP\Files\NotPermittedException;
 use OCP\IRequest;
@@ -88,12 +89,13 @@ public function deleteUser(string $userId): DataResponse {
 
 	#[NoCSRFRequired]
 	#[PublicPage]
-	public function getJwks(): DataResponse {
-		$jwks = $this->jwkService->getJwks();
-		return new DataResponse([
-			'keys' => [
-				$jwks['public'],
-			],
-		]);
+	public function getJwks(): JSONResponse {
+		try {
+			$jwk = $this->jwkService->getJwk();
+			return new JSONResponse(['keys' => [$jwk]]);
+			// return new JSONResponse($this->jwkService->debug());
+		} catch (\Exception|\Throwable $e) {
+			return new JSONResponse(['error' => $e->getMessage()], Http::STATUS_INTERNAL_SERVER_ERROR);
+		}
 	}
 }
diff --git a/lib/Service/JwkService.php b/lib/Service/JwkService.php
index 877e8ecc..bbbcbb3b 100644
--- a/lib/Service/JwkService.php
+++ b/lib/Service/JwkService.php
@@ -10,48 +10,135 @@
 
 require_once __DIR__ . '/../../vendor/autoload.php';
 
+use OCA\UserOIDC\Vendor\Firebase\JWT\JWK;
+use OCA\UserOIDC\Vendor\Firebase\JWT\JWT;
+use OCP\AppFramework\Services\IAppConfig;
+use OCP\Exceptions\AppConfigTypeConflictException;
+use Strobotti\JWK\Key\KeyInterface;
 use Strobotti\JWK\KeyFactory;
 
 class JwkService {
 
+	public const PEM_PRIVATE_KEY_SETTINGS_KEY = 'pemPrivateKey';
+	public const PEM_PRIVATE_KEY_EXPIRES_AT_SETTINGS_KEY = 'pemPrivateKeyExpiresAt';
+	public const PEM_PRIVATE_KEY_EXPIRES_IN_SECONDS = 60 * 2;
+
 	public function __construct(
+		private IAppConfig $appConfig,
 	) {
-
 	}
 
-	public function getJwks(): array {
-		$keyPair = $this->createKeyPair();
+	/**
+	 * Get our stored private PEM key (or regenerate it if it's expired)
+	 *
+	 * @param bool $refresh
+	 * @return string
+	 * @throws AppConfigTypeConflictException
+	 */
+	public function getMyPemPrivateKey(bool $refresh = true): string {
+		$pemPrivateKey = $this->appConfig->getAppValueString(self::PEM_PRIVATE_KEY_SETTINGS_KEY, lazy: true);
+		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_PRIVATE_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
 
-		$options = [
-			'use' => 'sig',
-			'alg' => 'sha512',
-			'kid' => 'plop',
-		];
-		$keyFactory = new KeyFactory();
-		$publicJwk = $keyFactory->createFromPem($keyPair['public'], $options);
-		// $privateJwk = $keyFactory->createFromPem($keyPair['private'], $options);
-		return [
-			'public' => $publicJwk,
-			//'private' => $privateJwk,
-		];
+		if ($pemPrivateKey === '' || $pemPrivateKeyExpiresAt === 0 || ($refresh && time() > $pemPrivateKeyExpiresAt)) {
+			$pemPrivateKey = $this->generatePemPrivateKey();
+			// store the key
+			$this->appConfig->setAppValueString(self::PEM_PRIVATE_KEY_SETTINGS_KEY, $pemPrivateKey, lazy: true);
+			$this->appConfig->setAppValueInt(self::PEM_PRIVATE_KEY_EXPIRES_AT_SETTINGS_KEY, time() + self::PEM_PRIVATE_KEY_EXPIRES_IN_SECONDS, lazy: true);
+		}
+		return $pemPrivateKey;
 	}
 
-	public function createKeyPair(): array {
+	/**
+	 * Generate a new full/private key and return it in PEM format
+	 *
+	 * @return string
+	 */
+	public function generatePemPrivateKey(): string {
 		$config = [
 			'digest_alg' => 'sha512',
 			'private_key_bits' => 4096,
+			// 'private_key_type' => OPENSSL_KEYTYPE_EC,
 			'private_key_type' => OPENSSL_KEYTYPE_RSA,
 		];
 
 		// Create the private and public key
 		$key = openssl_pkey_new($config);
 		openssl_pkey_export($key, $privKeyPem);
-		$pubKey = openssl_pkey_get_details($key);
+
+		return $privKeyPem;
+	}
+
+	/**
+	 * Get our stored private PEM key (or regenerate it if it's expired)
+	 * Extract the public key from the full/private key
+	 * Build a JWK from the public key
+	 *
+	 * @return array
+	 * @throws AppConfigTypeConflictException
+	 */
+	public function getJwk(): array {
+		$myPemPrivateKey = $this->getMyPemPrivateKey();
+		$sslPrivateKey = openssl_pkey_get_private($myPemPrivateKey);
+		$sslPublicKey = openssl_pkey_get_details($sslPrivateKey);
+		$pubKeyPem = $sslPublicKey['key'];
+		return $this->getJwkFromPem($pubKeyPem)->jsonSerialize();
+	}
+
+	/**
+	 * Build a JWK from a PEM (public) key
+	 *
+	 * @param string $pemKey
+	 * @return KeyInterface
+	 * @throws AppConfigTypeConflictException
+	 */
+	public function getJwkFromPem(string $pemKey): KeyInterface {
+		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_PRIVATE_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
+		$options = [
+			'use' => 'sig',
+			'alg' => 'RS512',
+			'kid' => 'key_' . $pemPrivateKeyExpiresAt,
+		];
+		$keyFactory = new KeyFactory();
+		return $keyFactory->createFromPem($pemKey, $options);
+	}
+
+	/**
+	 * Create a JWT token signed with a given private SSL key
+	 *
+	 * @param array $payload
+	 * @param \OpenSSLAsymmetricKey $key
+	 * @param string $keyId
+	 * @param string $alg
+	 * @return string
+	 */
+	public function createJwt(array $payload, \OpenSSLAsymmetricKey $key, string $keyId, string $alg = 'RS512'): string {
+		return JWT::encode($payload, $key, $alg, $keyId);
+	}
+
+	public function debug(): array {
+		$myPemPrivateKey = $this->getMyPemPrivateKey();
+		$sslPrivateKey = openssl_pkey_get_private($myPemPrivateKey);
+		$pubKey = openssl_pkey_get_details($sslPrivateKey);
 		$pubKeyPem = $pubKey['key'];
 
+		$payload = ['lll' => 'aaa'];
+		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_PRIVATE_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
+		$signedJwtToken = $this->createJwt($payload, $sslPrivateKey, 'key_' . $pemPrivateKeyExpiresAt, 'RS512');
+
+		// check content of JWT
+		$rawJwks = ['keys' => [$this->getJwkFromPem($pubKeyPem)->jsonSerialize()]];
+		$jwks = JWK::parseKeySet($rawJwks, 'RS512');
+		$jwtPayload = JWT::decode($signedJwtToken, $jwks);
+		$jwtPayloadArray = json_decode(json_encode($jwtPayload), true);
+
 		return [
-			'public' => $pubKeyPem,
-			'private' => $privKeyPem,
+			'public_jwk' => $this->getJwkFromPem($pubKeyPem)->jsonSerialize(),
+			'public_pem' => $pubKeyPem,
+			'private_pem' => $myPemPrivateKey,
+			'payload' => $payload,
+			'signed_jwt' => $signedJwtToken,
+			'jwt_payload' => $jwtPayloadArray,
+			'arrays_are_equal' => $payload === $jwtPayloadArray,
 		];
 	}
 }

From 279918559836959c9d34c276db97aefcb26ce7f6 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Tue, 28 Oct 2025 19:09:29 +0100
Subject: [PATCH 03/25] use EC signature key with P-384 curve

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 lib/Service/JwkService.php | 63 ++++++++++++++++++++++++++++++++------
 1 file changed, 53 insertions(+), 10 deletions(-)

diff --git a/lib/Service/JwkService.php b/lib/Service/JwkService.php
index bbbcbb3b..97d22d14 100644
--- a/lib/Service/JwkService.php
+++ b/lib/Service/JwkService.php
@@ -55,17 +55,20 @@ public function getMyPemPrivateKey(bool $refresh = true): string {
 	 */
 	public function generatePemPrivateKey(): string {
 		$config = [
-			'digest_alg' => 'sha512',
-			'private_key_bits' => 4096,
-			// 'private_key_type' => OPENSSL_KEYTYPE_EC,
-			'private_key_type' => OPENSSL_KEYTYPE_RSA,
+			// 'digest_alg' => 'sha512',
+			// 'private_key_bits' => 4096,
+			'private_key_type' => OPENSSL_KEYTYPE_EC,
+			// 'private_key_type' => OPENSSL_KEYTYPE_RSA,
+			// 'curve_name' => 'secp256r1',
+			'curve_name' => 'secp384r1',
+			// 'curve_name' => 'secp521r1',
 		];
 
 		// Create the private and public key
 		$key = openssl_pkey_new($config);
-		openssl_pkey_export($key, $privKeyPem);
+		openssl_pkey_export($key, $privateKeyPem);
 
-		return $privKeyPem;
+		return $privateKeyPem;
 	}
 
 	/**
@@ -80,8 +83,21 @@ public function getJwk(): array {
 		$myPemPrivateKey = $this->getMyPemPrivateKey();
 		$sslPrivateKey = openssl_pkey_get_private($myPemPrivateKey);
 		$sslPublicKey = openssl_pkey_get_details($sslPrivateKey);
-		$pubKeyPem = $sslPublicKey['key'];
-		return $this->getJwkFromPem($pubKeyPem)->jsonSerialize();
+		return $this->getSigJwkFromSslKey($sslPublicKey);
+		// $pubKeyPem = $sslPublicKey['key'];
+		// return $this->getJwkFromPem($pubKeyPem)->jsonSerialize();
+	}
+
+	public function getSigJwkFromSslKey(array $sslKey): array {
+		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_PRIVATE_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
+		return [
+			'kty' => 'EC',
+			'use' => 'sig',
+			'kid' => 'sig_key_' . $pemPrivateKeyExpiresAt,
+			'crv' => 'P-384',
+			'x' => \rtrim(\strtr(\base64_encode($sslKey['ec']['x']), '+/', '-_'), '='),
+			'y' => \rtrim(\strtr(\base64_encode($sslKey['ec']['y']), '+/', '-_'), '='),
+		];
 	}
 
 	/**
@@ -96,7 +112,7 @@ public function getJwkFromPem(string $pemKey): KeyInterface {
 		$options = [
 			'use' => 'sig',
 			'alg' => 'RS512',
-			'kid' => 'key_' . $pemPrivateKeyExpiresAt,
+			'kid' => 'sig_key_' . $pemPrivateKeyExpiresAt,
 		];
 		$keyFactory = new KeyFactory();
 		return $keyFactory->createFromPem($pemKey, $options);
@@ -123,7 +139,34 @@ public function debug(): array {
 
 		$payload = ['lll' => 'aaa'];
 		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_PRIVATE_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
-		$signedJwtToken = $this->createJwt($payload, $sslPrivateKey, 'key_' . $pemPrivateKeyExpiresAt, 'RS512');
+		$signedJwtToken = $this->createJwt($payload, $sslPrivateKey, 'sig_key_' . $pemPrivateKeyExpiresAt, 'RS512');
+
+		// check content of JWT
+		$rawJwks = ['keys' => [$this->getSigJwkFromSslKey($pubKey)]];
+		$jwks = JWK::parseKeySet($rawJwks, 'RS512');
+		$jwtPayload = JWT::decode($signedJwtToken, $jwks);
+		$jwtPayloadArray = json_decode(json_encode($jwtPayload), true);
+
+		return [
+			'public_jwk' => $this->getSigJwkFromSslKey($pubKey),
+			'public_pem' => $pubKeyPem,
+			'private_pem' => $myPemPrivateKey,
+			'payload' => $payload,
+			'signed_jwt' => $signedJwtToken,
+			'jwt_payload' => $jwtPayloadArray,
+			'arrays_are_equal' => $payload === $jwtPayloadArray,
+		];
+	}
+
+	public function debugRSA(): array {
+		$myPemPrivateKey = $this->getMyPemPrivateKey();
+		$sslPrivateKey = openssl_pkey_get_private($myPemPrivateKey);
+		$pubKey = openssl_pkey_get_details($sslPrivateKey);
+		$pubKeyPem = $pubKey['key'];
+
+		$payload = ['lll' => 'aaa'];
+		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_PRIVATE_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
+		$signedJwtToken = $this->createJwt($payload, $sslPrivateKey, 'sig_key_' . $pemPrivateKeyExpiresAt);
 
 		// check content of JWT
 		$rawJwks = ['keys' => [$this->getJwkFromPem($pubKeyPem)->jsonSerialize()]];

From 7aa458f42ff3020ec6aa867d26c8f5953c2f5b44 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Wed, 29 Oct 2025 11:33:25 +0100
Subject: [PATCH 04/25] generate/store/refresh encryption key

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 lib/Controller/ApiController.php |   4 +-
 lib/Service/JwkService.php       | 112 +++++++++++++++++++++----------
 2 files changed, 78 insertions(+), 38 deletions(-)

diff --git a/lib/Controller/ApiController.php b/lib/Controller/ApiController.php
index 9d777c32..c4c15313 100644
--- a/lib/Controller/ApiController.php
+++ b/lib/Controller/ApiController.php
@@ -91,8 +91,8 @@ public function deleteUser(string $userId): DataResponse {
 	#[PublicPage]
 	public function getJwks(): JSONResponse {
 		try {
-			$jwk = $this->jwkService->getJwk();
-			return new JSONResponse(['keys' => [$jwk]]);
+			$jwks = $this->jwkService->getJwks();
+			return new JSONResponse(['keys' => $jwks]);
 			// return new JSONResponse($this->jwkService->debug());
 		} catch (\Exception|\Throwable $e) {
 			return new JSONResponse(['error' => $e->getMessage()], Http::STATUS_INTERNAL_SERVER_ERROR);
diff --git a/lib/Service/JwkService.php b/lib/Service/JwkService.php
index 97d22d14..dbfede28 100644
--- a/lib/Service/JwkService.php
+++ b/lib/Service/JwkService.php
@@ -19,9 +19,13 @@
 
 class JwkService {
 
-	public const PEM_PRIVATE_KEY_SETTINGS_KEY = 'pemPrivateKey';
-	public const PEM_PRIVATE_KEY_EXPIRES_AT_SETTINGS_KEY = 'pemPrivateKeyExpiresAt';
-	public const PEM_PRIVATE_KEY_EXPIRES_IN_SECONDS = 60 * 2;
+	public const PEM_SIG_KEY_SETTINGS_KEY = 'pemSignatureKey';
+	public const PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY = 'pemSignatureKeyExpiresAt';
+	public const PEM_SIG_KEY_EXPIRES_IN_SECONDS = 60 * 2;
+
+	public const PEM_ENC_KEY_SETTINGS_KEY = 'pemEncryptionKey';
+	public const PEM_ENC_KEY_EXPIRES_AT_SETTINGS_KEY = 'pemEncryptionKeyExpiresAt';
+	public const PEM_ENC_KEY_EXPIRES_IN_SECONDS = 60 * 2;
 
 	public function __construct(
 		private IAppConfig $appConfig,
@@ -29,23 +33,43 @@ public function __construct(
 	}
 
 	/**
-	 * Get our stored private PEM key (or regenerate it if it's expired)
+	 * Get our stored signature PEM key (or regenerate it if it's expired)
+	 *
+	 * @param bool $refresh
+	 * @return string
+	 * @throws AppConfigTypeConflictException
+	 */
+	public function getMyPemSignatureKey(bool $refresh = true): string {
+		$pemSignatureKey = $this->appConfig->getAppValueString(self::PEM_SIG_KEY_SETTINGS_KEY, lazy: true);
+		$pemSignatureKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
+
+		if ($pemSignatureKey === '' || $pemSignatureKeyExpiresAt === 0 || ($refresh && time() > $pemSignatureKeyExpiresAt)) {
+			$pemSignatureKey = $this->generatePemPrivateKey();
+			// store the key
+			$this->appConfig->setAppValueString(self::PEM_SIG_KEY_SETTINGS_KEY, $pemSignatureKey, lazy: true);
+			$this->appConfig->setAppValueInt(self::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, time() + self::PEM_SIG_KEY_EXPIRES_IN_SECONDS, lazy: true);
+		}
+		return $pemSignatureKey;
+	}
+
+	/**
+	 * Get our stored encryption PEM key (or regenerate it if it's expired)
 	 *
 	 * @param bool $refresh
 	 * @return string
 	 * @throws AppConfigTypeConflictException
 	 */
-	public function getMyPemPrivateKey(bool $refresh = true): string {
-		$pemPrivateKey = $this->appConfig->getAppValueString(self::PEM_PRIVATE_KEY_SETTINGS_KEY, lazy: true);
-		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_PRIVATE_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
+	public function getMyEncryptionKey(bool $refresh = true): string {
+		$pemEncryptionKey = $this->appConfig->getAppValueString(self::PEM_ENC_KEY_SETTINGS_KEY, lazy: true);
+		$pemEncryptionKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_ENC_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
 
-		if ($pemPrivateKey === '' || $pemPrivateKeyExpiresAt === 0 || ($refresh && time() > $pemPrivateKeyExpiresAt)) {
-			$pemPrivateKey = $this->generatePemPrivateKey();
+		if ($pemEncryptionKey === '' || $pemEncryptionKeyExpiresAt === 0 || ($refresh && time() > $pemEncryptionKeyExpiresAt)) {
+			$pemEncryptionKey = $this->generatePemPrivateKey();
 			// store the key
-			$this->appConfig->setAppValueString(self::PEM_PRIVATE_KEY_SETTINGS_KEY, $pemPrivateKey, lazy: true);
-			$this->appConfig->setAppValueInt(self::PEM_PRIVATE_KEY_EXPIRES_AT_SETTINGS_KEY, time() + self::PEM_PRIVATE_KEY_EXPIRES_IN_SECONDS, lazy: true);
+			$this->appConfig->setAppValueString(self::PEM_ENC_KEY_SETTINGS_KEY, $pemEncryptionKey, lazy: true);
+			$this->appConfig->setAppValueInt(self::PEM_ENC_KEY_EXPIRES_AT_SETTINGS_KEY, time() + self::PEM_ENC_KEY_EXPIRES_IN_SECONDS, lazy: true);
 		}
-		return $pemPrivateKey;
+		return $pemEncryptionKey;
 	}
 
 	/**
@@ -55,7 +79,7 @@ public function getMyPemPrivateKey(bool $refresh = true): string {
 	 */
 	public function generatePemPrivateKey(): string {
 		$config = [
-			// 'digest_alg' => 'sha512',
+			// 'digest_alg' => 'ES384',
 			// 'private_key_bits' => 4096,
 			'private_key_type' => OPENSSL_KEYTYPE_EC,
 			// 'private_key_type' => OPENSSL_KEYTYPE_RSA,
@@ -79,25 +103,36 @@ public function generatePemPrivateKey(): string {
 	 * @return array
 	 * @throws AppConfigTypeConflictException
 	 */
-	public function getJwk(): array {
-		$myPemPrivateKey = $this->getMyPemPrivateKey();
-		$sslPrivateKey = openssl_pkey_get_private($myPemPrivateKey);
-		$sslPublicKey = openssl_pkey_get_details($sslPrivateKey);
-		return $this->getSigJwkFromSslKey($sslPublicKey);
+	public function getJwks(): array {
+		$myPemSignatureKey = $this->getMyPemSignatureKey(false);
+		$sslSignatureKey = openssl_pkey_get_private($myPemSignatureKey);
+		$sslSignatureKeyDetails = openssl_pkey_get_details($sslSignatureKey);
+
+		$myPemEncryptionKey = $this->getMyEncryptionKey(true);
+		$sslEncryptionKey = openssl_pkey_get_private($myPemEncryptionKey);
+		$sslEncryptionKeyDetails = openssl_pkey_get_details($sslEncryptionKey);
+		return [
+			$this->getJwkFromSslKey($sslSignatureKeyDetails),
+			$this->getJwkFromSslKey($sslEncryptionKeyDetails, isEncryptionKey: true),
+		];
 		// $pubKeyPem = $sslPublicKey['key'];
 		// return $this->getJwkFromPem($pubKeyPem)->jsonSerialize();
 	}
 
-	public function getSigJwkFromSslKey(array $sslKey): array {
-		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_PRIVATE_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
-		return [
+	public function getJwkFromSslKey(array $sslKeyDetails, bool $isEncryptionKey = false): array {
+		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
+		$jwk = [
 			'kty' => 'EC',
-			'use' => 'sig',
-			'kid' => 'sig_key_' . $pemPrivateKeyExpiresAt,
+			'use' => $isEncryptionKey ? 'enc' : 'sig',
+			'kid' => ($isEncryptionKey ? 'enc' : 'sig') . '_key_' . $pemPrivateKeyExpiresAt,
 			'crv' => 'P-384',
-			'x' => \rtrim(\strtr(\base64_encode($sslKey['ec']['x']), '+/', '-_'), '='),
-			'y' => \rtrim(\strtr(\base64_encode($sslKey['ec']['y']), '+/', '-_'), '='),
+			'x' => \rtrim(\strtr(\base64_encode($sslKeyDetails['ec']['x']), '+/', '-_'), '='),
+			'y' => \rtrim(\strtr(\base64_encode($sslKeyDetails['ec']['y']), '+/', '-_'), '='),
 		];
+		if ($isEncryptionKey) {
+			$jwk['alg'] = 'ECDH-ES+A192KW';
+		}
+		return $jwk;
 	}
 
 	/**
@@ -108,7 +143,7 @@ public function getSigJwkFromSslKey(array $sslKey): array {
 	 * @throws AppConfigTypeConflictException
 	 */
 	public function getJwkFromPem(string $pemKey): KeyInterface {
-		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_PRIVATE_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
+		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
 		$options = [
 			'use' => 'sig',
 			'alg' => 'RS512',
@@ -132,40 +167,45 @@ public function createJwt(array $payload, \OpenSSLAsymmetricKey $key, string $ke
 	}
 
 	public function debug(): array {
-		$myPemPrivateKey = $this->getMyPemPrivateKey();
+		$myPemPrivateKey = $this->getMyPemSignatureKey();
 		$sslPrivateKey = openssl_pkey_get_private($myPemPrivateKey);
 		$pubKey = openssl_pkey_get_details($sslPrivateKey);
 		$pubKeyPem = $pubKey['key'];
 
 		$payload = ['lll' => 'aaa'];
-		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_PRIVATE_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
-		$signedJwtToken = $this->createJwt($payload, $sslPrivateKey, 'sig_key_' . $pemPrivateKeyExpiresAt, 'RS512');
+		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
+		$signedJwtToken = $this->createJwt($payload, $sslPrivateKey, 'sig_key_' . $pemPrivateKeyExpiresAt, 'ES384');
 
 		// check content of JWT
-		$rawJwks = ['keys' => [$this->getSigJwkFromSslKey($pubKey)]];
-		$jwks = JWK::parseKeySet($rawJwks, 'RS512');
+		$rawJwks = ['keys' => [$this->getJwkFromSslKey($pubKey)]];
+		$jwks = JWK::parseKeySet($rawJwks, 'ES384');
 		$jwtPayload = JWT::decode($signedJwtToken, $jwks);
 		$jwtPayloadArray = json_decode(json_encode($jwtPayload), true);
 
+		// check header of JWT
+		$jwtParts = explode('.', $signedJwtToken, 3);
+		$jwtHeader = json_decode(JWT::urlsafeB64Decode($jwtParts[0]), true);
+
 		return [
-			'public_jwk' => $this->getSigJwkFromSslKey($pubKey),
+			'public_jwk' => $this->getJwkFromSslKey($pubKey),
 			'public_pem' => $pubKeyPem,
 			'private_pem' => $myPemPrivateKey,
-			'payload' => $payload,
+			'initial_payload' => $payload,
 			'signed_jwt' => $signedJwtToken,
-			'jwt_payload' => $jwtPayloadArray,
+			'jwt_header' => $jwtHeader,
+			'decoded_jwt_payload' => $jwtPayloadArray,
 			'arrays_are_equal' => $payload === $jwtPayloadArray,
 		];
 	}
 
 	public function debugRSA(): array {
-		$myPemPrivateKey = $this->getMyPemPrivateKey();
+		$myPemPrivateKey = $this->getMyPemSignatureKey();
 		$sslPrivateKey = openssl_pkey_get_private($myPemPrivateKey);
 		$pubKey = openssl_pkey_get_details($sslPrivateKey);
 		$pubKeyPem = $pubKey['key'];
 
 		$payload = ['lll' => 'aaa'];
-		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_PRIVATE_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
+		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
 		$signedJwtToken = $this->createJwt($payload, $sslPrivateKey, 'sig_key_' . $pemPrivateKeyExpiresAt);
 
 		// check content of JWT

From 7d1a1ec12abe2b7fa933fd5da162097d8d3dfe23 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Wed, 29 Oct 2025 12:45:24 +0100
Subject: [PATCH 05/25] add lint-eslint action

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 .github/workflows/lint-eslint.yml | 100 ++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 .github/workflows/lint-eslint.yml

diff --git a/.github/workflows/lint-eslint.yml b/.github/workflows/lint-eslint.yml
new file mode 100644
index 00000000..0a535f77
--- /dev/null
+++ b/.github/workflows/lint-eslint.yml
@@ -0,0 +1,100 @@
+# This workflow is provided via the organization template repository
+#
+# https://github.com/nextcloud/.github
+# https://docs.github.com/en/actions/learn-github-actions/sharing-workflows-with-your-organization
+#
+# SPDX-FileCopyrightText: 2021-2024 Nextcloud GmbH and Nextcloud contributors
+# SPDX-License-Identifier: MIT
+
+name: Lint eslint
+
+on: pull_request
+
+permissions:
+  contents: read
+
+concurrency:
+  group: lint-eslint-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  changes:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: read
+
+    outputs:
+      src: ${{ steps.changes.outputs.src}}
+
+    steps:
+      - uses: dorny/paths-filter@de90cc6fb38fc0963ad72b210f1f284cd68cea36 # v3.0.2
+        id: changes
+        continue-on-error: true
+        with:
+          filters: |
+            src:
+              - '.github/workflows/**'
+              - 'src/**'
+              - 'appinfo/info.xml'
+              - 'package.json'
+              - 'package-lock.json'
+              - 'tsconfig.json'
+              - '.eslintrc.*'
+              - '.eslintignore'
+              - '**.js'
+              - '**.ts'
+              - '**.vue'
+
+  lint:
+    runs-on: ubuntu-latest
+
+    needs: changes
+    if: needs.changes.outputs.src != 'false'
+
+    name: NPM lint
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+        with:
+          persist-credentials: false
+
+      - name: Read package.json node and npm engines version
+        uses: skjnldsv/read-package-engines-version-actions@06d6baf7d8f41934ab630e97d9e6c0bc9c9ac5e4 # v3
+        id: versions
+        with:
+          fallbackNode: '^20'
+          fallbackNpm: '^10'
+
+      - name: Set up node ${{ steps.versions.outputs.nodeVersion }}
+        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
+        with:
+          node-version: ${{ steps.versions.outputs.nodeVersion }}
+
+      - name: Set up npm ${{ steps.versions.outputs.npmVersion }}
+        run: npm i -g 'npm@${{ steps.versions.outputs.npmVersion }}'
+
+      - name: Install dependencies
+        env:
+          CYPRESS_INSTALL_BINARY: 0
+          PUPPETEER_SKIP_DOWNLOAD: true
+        run: npm ci
+
+      - name: Lint
+        run: npm run lint
+
+  summary:
+    permissions:
+      contents: none
+    runs-on: ubuntu-latest
+    needs: [changes, lint]
+
+    if: always()
+
+    # This is the summary, we just avoid to rename it so that branch protection rules still match
+    name: eslint
+
+    steps:
+      - name: Summary status
+        run: if ${{ needs.changes.outputs.src != 'false' && needs.lint.result != 'success' }}; then exit 1; fi

From 0590bb1a1f6084a134423d4a3b5e88943552dec4 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Wed, 29 Oct 2025 12:59:41 +0100
Subject: [PATCH 06/25] add new boolean setting to enable private key jwt auth

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 lib/Command/UpsertProvider.php             |  4 ++++
 lib/Service/JwkService.php                 |  4 +---
 lib/Service/ProviderService.php            |  3 +++
 src/components/AdminSettings.vue           |  1 +
 src/components/SettingsForm.vue            | 20 ++++++++++++++++++--
 tests/unit/Service/ProviderServiceTest.php |  4 ++++
 6 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/lib/Command/UpsertProvider.php b/lib/Command/UpsertProvider.php
index 83e4b817..be9238aa 100644
--- a/lib/Command/UpsertProvider.php
+++ b/lib/Command/UpsertProvider.php
@@ -27,6 +27,10 @@ class UpsertProvider extends Base {
 			'shortcut' => null, 'mode' => InputOption::VALUE_REQUIRED, 'setting_key' => ProviderService::SETTING_UNIQUE_UID,
 			'description' => 'Determines if unique user ids shall be used or not. 1 to enable, 0 to disable',
 		],
+		'use-private-key-jwt' => [
+			'shortcut' => null, 'mode' => InputOption::VALUE_REQUIRED, 'setting_key' => ProviderService::SETTING_USE_PRIVATE_KEY_JWT,
+			'description' => 'If enabled, user_oidc will use the private key JWT authentication method instead of using the client secret. 1 to enable, 0 to disable (default when creating a new provider)',
+		],
 		'check-bearer' => [
 			'shortcut' => null, 'mode' => InputOption::VALUE_REQUIRED, 'setting_key' => ProviderService::SETTING_CHECK_BEARER,
 			'description' => 'Determines if Nextcloud API/WebDav calls should check the Bearer token against this provider or not. 1 to enable, 0 to disable (default when creating a new provider)',
diff --git a/lib/Service/JwkService.php b/lib/Service/JwkService.php
index dbfede28..69567446 100644
--- a/lib/Service/JwkService.php
+++ b/lib/Service/JwkService.php
@@ -128,10 +128,8 @@ public function getJwkFromSslKey(array $sslKeyDetails, bool $isEncryptionKey = f
 			'crv' => 'P-384',
 			'x' => \rtrim(\strtr(\base64_encode($sslKeyDetails['ec']['x']), '+/', '-_'), '='),
 			'y' => \rtrim(\strtr(\base64_encode($sslKeyDetails['ec']['y']), '+/', '-_'), '='),
+			'alg' => $isEncryptionKey ? 'ECDH-ES+A192KW' : 'ES384',
 		];
-		if ($isEncryptionKey) {
-			$jwk['alg'] = 'ECDH-ES+A192KW';
-		}
 		return $jwk;
 	}
 
diff --git a/lib/Service/ProviderService.php b/lib/Service/ProviderService.php
index f5a82a51..30087274 100644
--- a/lib/Service/ProviderService.php
+++ b/lib/Service/ProviderService.php
@@ -23,6 +23,7 @@
  */
 class ProviderService {
 	public const SETTING_CHECK_BEARER = 'checkBearer';
+	public const SETTING_USE_PRIVATE_KEY_JWT = 'usePrivateKeyJwt';
 	public const SETTING_SEND_ID_TOKEN_HINT = 'sendIdTokenHint';
 	public const SETTING_BEARER_PROVISIONING = 'bearerProvisioning';
 	public const SETTING_UNIQUE_UID = 'uniqueUid';
@@ -68,6 +69,7 @@ class ProviderService {
 		self::SETTING_BEARER_PROVISIONING => false,
 		self::SETTING_UNIQUE_UID => true,
 		self::SETTING_CHECK_BEARER => false,
+		self::SETTING_USE_PRIVATE_KEY_JWT => false,
 		self::SETTING_SEND_ID_TOKEN_HINT => false,
 		self::SETTING_RESTRICT_LOGIN_TO_GROUPS => false,
 		self::SETTING_AZURE_GROUP_NAMES => false,
@@ -186,6 +188,7 @@ public function getSupportedSettings(): array {
 			self::SETTING_MAPPING_BIRTHDATE,
 			self::SETTING_UNIQUE_UID,
 			self::SETTING_CHECK_BEARER,
+			self::SETTING_USE_PRIVATE_KEY_JWT,
 			self::SETTING_SEND_ID_TOKEN_HINT,
 			self::SETTING_BEARER_PROVISIONING,
 			self::SETTING_EXTRA_CLAIMS,
diff --git a/src/components/AdminSettings.vue b/src/components/AdminSettings.vue
index ea630bfb..06c1fe93 100644
--- a/src/components/AdminSettings.vue
+++ b/src/components/AdminSettings.vue
@@ -197,6 +197,7 @@ export default {
 				endSessionEndpoint: '',
 				postLogoutUri: '',
 				settings: {
+					usePrivateKeyJwt: false,
 					uniqueUid: true,
 					checkBearer: false,
 					bearerProvisioning: false,
diff --git a/src/components/SettingsForm.vue b/src/components/SettingsForm.vue
index 8abdab66..fda6d04d 100644
--- a/src/components/SettingsForm.vue
+++ b/src/components/SettingsForm.vue
@@ -23,13 +23,21 @@
 				type="text"
 				required>
 		</p>
+		<NcCheckboxRadioSwitch
+			v-model="localProvider.settings.usePrivateKeyJwt"
+			wrapper-element="div">
+			{{ t('user_oidc', 'Use private key JWT authentication method') }}
+		</NcCheckboxRadioSwitch>
+		<!-- TODO: link to https://openid.net/specs/openid-connect-core-1_0.html#ClientAuthentication -->
+		<!-- TODO: give the JWKs URL to configure the IdP -->
 		<p>
 			<label for="oidc-client-secret">{{ t('user_oidc', 'Client secret') }}</label>
 			<input id="oidc-client-secret"
 				v-model="localProvider.clientSecret"
-				:placeholder="update ? t('user_oidc', 'Leave empty to keep existing') : null"
+				:placeholder="clientSecretPlaceholder"
 				type="text"
-				:required="!update"
+				:disabled="localProvider.settings.usePrivateKeyJwt"
+				:required="!update && !localProvider.settings.usePrivateKeyJwt"
 				autocomplete="off">
 		</p>
 		<p class="settings-hint warning-hint">
@@ -397,6 +405,14 @@ export default {
 		identifierLength() {
 			return this.localProvider.identifier.length
 		},
+		clientSecretPlaceholder() {
+			if (this.localProvider.settings.usePrivateKeyJwt) {
+				return t('user_oidc', 'Not used with private key JWT authentication')
+			}
+			return this.update
+				? t('user_oidc', 'Leave empty to keep existing')
+				: null
+		},
 	},
 	created() {
 		this.localProvider = this.provider
diff --git a/tests/unit/Service/ProviderServiceTest.php b/tests/unit/Service/ProviderServiceTest.php
index 24fd9ffb..cdf58683 100644
--- a/tests/unit/Service/ProviderServiceTest.php
+++ b/tests/unit/Service/ProviderServiceTest.php
@@ -90,6 +90,7 @@ public function testGetProvidersWithSettings() {
 					'mappingBirthdate' => '1',
 					'uniqueUid' => true,
 					'checkBearer' => true,
+					'usePrivateKeyJwt' => true,
 					'bearerProvisioning' => true,
 					'sendIdTokenHint' => true,
 					'extraClaims' => '1',
@@ -137,6 +138,7 @@ public function testGetProvidersWithSettings() {
 					'mappingBirthdate' => '1',
 					'uniqueUid' => true,
 					'checkBearer' => true,
+					'usePrivateKeyJwt' => true,
 					'bearerProvisioning' => true,
 					'sendIdTokenHint' => true,
 					'extraClaims' => '1',
@@ -160,6 +162,7 @@ public function testSetSettings() {
 			'mappingGroups' => 'groups',
 			'uniqueUid' => true,
 			'checkBearer' => false,
+			'usePrivateKeyJwt' => false,
 			'bearerProvisioning' => false,
 			'sendIdTokenHint' => true,
 			'extraClaims' => 'claim1 claim2',
@@ -220,6 +223,7 @@ public function testSetSettings() {
 				[Application::APP_ID, 'provider-1-' . ProviderService::SETTING_MAPPING_BIRTHDATE, '', true, 'birthdate'],
 				[Application::APP_ID, 'provider-1-' . ProviderService::SETTING_UNIQUE_UID, '', true, '1'],
 				[Application::APP_ID, 'provider-1-' . ProviderService::SETTING_CHECK_BEARER, '', true, '0'],
+				[Application::APP_ID, 'provider-1-' . ProviderService::SETTING_USE_PRIVATE_KEY_JWT, '', true, '0'],
 				[Application::APP_ID, 'provider-1-' . ProviderService::SETTING_BEARER_PROVISIONING, '', true, '0'],
 				[Application::APP_ID, 'provider-1-' . ProviderService::SETTING_SEND_ID_TOKEN_HINT, '', true, '1'],
 				[Application::APP_ID, 'provider-1-' . ProviderService::SETTING_EXTRA_CLAIMS, '', true, 'claim1 claim2'],

From 9ae4166dcf8475676d7708496017120c4848b1db Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Wed, 29 Oct 2025 16:48:49 +0100
Subject: [PATCH 07/25] implement private jwt login flow by passing the client
 assertion to the token endpoint

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 lib/Controller/LoginController.php | 13 +++++++++++--
 lib/Service/JwkService.php         | 22 ++++++++++++++++++++++
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/lib/Controller/LoginController.php b/lib/Controller/LoginController.php
index 9835620d..f5fc9869 100644
--- a/lib/Controller/LoginController.php
+++ b/lib/Controller/LoginController.php
@@ -21,6 +21,7 @@
 use OCA\UserOIDC\Event\TokenObtainedEvent;
 use OCA\UserOIDC\Helper\HttpClientHelper;
 use OCA\UserOIDC\Service\DiscoveryService;
+use OCA\UserOIDC\Service\JwkService;
 use OCA\UserOIDC\Service\LdapService;
 use OCA\UserOIDC\Service\OIDCService;
 use OCA\UserOIDC\Service\ProviderService;
@@ -101,6 +102,7 @@ public function __construct(
 		private TokenService $tokenService,
 		private OidcService $oidcService,
 		private ServerVersion $serverVersion,
+		private JwkService $jwkService,
 	) {
 		parent::__construct($request, $config, $l10n);
 	}
@@ -402,6 +404,7 @@ public function code(string $state = '', string $code = '', string $scope = '',
 		$oidcSystemConfig = $this->config->getSystemValue('user_oidc', []);
 		$isPkceSupported = in_array('S256', $discovery['code_challenge_methods_supported'] ?? [], true);
 		$isPkceEnabled = $isPkceSupported && ($oidcSystemConfig['use_pkce'] ?? true);
+		$usePrivateKeyJwt = $this->providerService->getSetting($providerId, ProviderService::SETTING_USE_PRIVATE_KEY_JWT, '0') !== '0';
 
 		try {
 			$requestBody = [
@@ -431,7 +434,8 @@ public function code(string $state = '', string $code = '', string $scope = '',
 				$tokenEndpointAuthMethod = 'client_secret_post';
 			}
 
-			if ($tokenEndpointAuthMethod === 'client_secret_basic') {
+			// private key JWT auth does not work with client_secret_basic, we don't wanna pass the client secret
+			if ($tokenEndpointAuthMethod === 'client_secret_basic' && !$usePrivateKeyJwt) {
 				$headers = [
 					'Authorization' => 'Basic ' . base64_encode($provider->getClientId() . ':' . $providerClientSecret),
 					'Content-Type' => 'application/x-www-form-urlencoded',
@@ -439,7 +443,12 @@ public function code(string $state = '', string $code = '', string $scope = '',
 			} else {
 				// Assuming client_secret_post as no other option is supported currently
 				$requestBody['client_id'] = $provider->getClientId();
-				$requestBody['client_secret'] = $providerClientSecret;
+				if ($usePrivateKeyJwt) {
+					$requestBody['client_assertion_type'] = 'urn:ietf:params:oauth:client-assertion-type:jwt-bearer';
+					$requestBody['client_assertion'] = $this->jwkService->generateClientAssertion($provider, $discovery['issuer'], $code);
+				} else {
+					$requestBody['client_secret'] = $providerClientSecret;
+				}
 			}
 
 			$body = $this->clientService->post(
diff --git a/lib/Service/JwkService.php b/lib/Service/JwkService.php
index 69567446..33c8d258 100644
--- a/lib/Service/JwkService.php
+++ b/lib/Service/JwkService.php
@@ -10,6 +10,7 @@
 
 require_once __DIR__ . '/../../vendor/autoload.php';
 
+use OCA\UserOIDC\Db\Provider;
 use OCA\UserOIDC\Vendor\Firebase\JWT\JWK;
 use OCA\UserOIDC\Vendor\Firebase\JWT\JWT;
 use OCP\AppFramework\Services\IAppConfig;
@@ -164,6 +165,27 @@ public function createJwt(array $payload, \OpenSSLAsymmetricKey $key, string $ke
 		return JWT::encode($payload, $key, $alg, $keyId);
 	}
 
+	public function generateClientAssertion(Provider $provider, string $discoveryIssuer, ?string $code = null): string {
+		$myPemPrivateKey = $this->getMyPemSignatureKey();
+		$sslPrivateKey = openssl_pkey_get_private($myPemPrivateKey);
+		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
+
+		$payload = [
+			'sub' => $provider->getClientId(),
+			'aud' => $discoveryIssuer,
+			'iss' => $provider->getClientId(),
+			'iat' => time(),
+			'exp' => time() + 60,
+			'jti' => \bin2hex(\random_bytes(16)),
+		];
+
+		if ($code !== null) {
+			$payload['code'] = $code;
+		}
+
+		return $this->createJwt($payload, $sslPrivateKey, 'sig_key_' . $pemPrivateKeyExpiresAt, 'ES384');
+	}
+
 	public function debug(): array {
 		$myPemPrivateKey = $this->getMyPemSignatureKey();
 		$sslPrivateKey = openssl_pkey_get_private($myPemPrivateKey);

From f0ff9f2e4d19994e3228003d3c9ef13eecb62a6b Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Wed, 29 Oct 2025 17:25:40 +0100
Subject: [PATCH 08/25] adjust README and settings UI

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 README.md                       | 16 +++++++++++++++
 src/components/SettingsForm.vue | 36 ++++++++++++++++++++++++++-------
 2 files changed, 45 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index fc315ea9..6590cc04 100644
--- a/README.md
+++ b/README.md
@@ -218,6 +218,22 @@ parameter to the login URL.
 sudo -u www-data php var/www/nextcloud/occ config:app:set --type=string --value=0 user_oidc allow_multiple_user_backends
 ```
 
+### Private key JWT authentication
+
+This app supports private key JWT authentication.
+See the `private_key_jwt` authentication method in https://openid.net/specs/openid-connect-core-1_0.html#ClientAuthentication
+This can be enabled for each provider individually in their settings
+(in Nextcloud's admin settings or with the `occ user_oidc:provider` command`).
+
+If you enable that for a provider, you must configure the client accordingly on the IdP side.
+In the IdP client settings, you should be able to make it accept a signed JWT and set the JWKS URL.
+
+The JWKS URL you should set in your IdP's client settings is `https://<your-nextcloud-url>/index.php/apps/user_oidc/jwks`.
+The exact URL is displayed in the user_oidc admin settings.
+
+In Keycloak, you can set the JWKS URL in the "Keys" tab of the client settings. Then you can choose "Signed Jwt"
+as the "Client Authenticator" in the "Credentials" tab.
+
 ### PKCE
 
 This app supports PKCE (Proof Key for Code Exchange).
diff --git a/src/components/SettingsForm.vue b/src/components/SettingsForm.vue
index fda6d04d..121f7d1c 100644
--- a/src/components/SettingsForm.vue
+++ b/src/components/SettingsForm.vue
@@ -23,13 +23,24 @@
 				type="text"
 				required>
 		</p>
-		<NcCheckboxRadioSwitch
-			v-model="localProvider.settings.usePrivateKeyJwt"
-			wrapper-element="div">
-			{{ t('user_oidc', 'Use private key JWT authentication method') }}
-		</NcCheckboxRadioSwitch>
-		<!-- TODO: link to https://openid.net/specs/openid-connect-core-1_0.html#ClientAuthentication -->
-		<!-- TODO: give the JWKs URL to configure the IdP -->
+		<div class="line">
+			<NcCheckboxRadioSwitch
+				v-model="localProvider.settings.usePrivateKeyJwt"
+				wrapper-element="div">
+				{{ t('user_oidc', 'Use private key JWT authentication method') }}
+			</NcCheckboxRadioSwitch>
+			<a href="https://github.com/nextcloud/user_oidc#private-key-jwt-authentication" target="_blank">
+				<NcButton variant="tertiary"
+					:title="t('user_oidc', 'More details on private key JWT authentication method')">
+					<template #icon>
+						<HelpCircleOutlineIcon />
+					</template>
+				</NcButton>
+			</a>
+		</div>
+		<NcNoteCard v-if="localProvider.settings.usePrivateKeyJwt" type="info">
+			{{ t('user_oidc', 'Use this JWKS URL in your IdP\'s client settings: {jwksUrl}', { jwksUrl }) }}
+		</NcNoteCard>
 		<p>
 			<label for="oidc-client-secret">{{ t('user_oidc', 'Client secret') }}</label>
 			<input id="oidc-client-secret"
@@ -360,11 +371,14 @@ import AlertOutlineIcon from 'vue-material-design-icons/AlertOutline.vue'
 import CheckIcon from 'vue-material-design-icons/Check.vue'
 import ChevronRightIcon from 'vue-material-design-icons/ChevronRight.vue'
 import ChevronDownIcon from 'vue-material-design-icons/ChevronDown.vue'
+import HelpCircleOutlineIcon from 'vue-material-design-icons/HelpCircleOutline.vue'
 
 import NcCheckboxRadioSwitch from '@nextcloud/vue/components/NcCheckboxRadioSwitch'
 import NcButton from '@nextcloud/vue/components/NcButton'
 import NcNoteCard from '@nextcloud/vue/components/NcNoteCard'
 
+import { generateUrl } from '@nextcloud/router'
+
 export default {
 	name: 'SettingsForm',
 	components: {
@@ -375,6 +389,7 @@ export default {
 		CheckIcon,
 		ChevronRightIcon,
 		ChevronDownIcon,
+		HelpCircleOutlineIcon,
 	},
 	props: {
 		submitText: {
@@ -399,6 +414,7 @@ export default {
 			localProvider: null,
 			maxIdentifierLength: 128,
 			showProfileAttributes: false,
+			jwksUrl: window.location.protocol + '//' + window.location.host + generateUrl('/apps/user_oidc/jwks'),
 		}
 	},
 	computed: {
@@ -450,6 +466,12 @@ export default {
 		}
 	}
 
+	.line {
+		display: flex;
+		align-items: center;
+		margin: 4px 0;
+	}
+
 	.warning-hint {
 		margin-left: 160px;
 		background-color: var(--color-background-dark);

From a98ce4e3fa3a718ec5acb6c9d79235d69c1e3fb6 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Mon, 3 Nov 2025 15:42:15 +0100
Subject: [PATCH 09/25] increase key lifetime to one hour, add comments on
 when/why we refresh

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 lib/Service/JwkService.php | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/Service/JwkService.php b/lib/Service/JwkService.php
index 33c8d258..53aebeaf 100644
--- a/lib/Service/JwkService.php
+++ b/lib/Service/JwkService.php
@@ -22,11 +22,11 @@ class JwkService {
 
 	public const PEM_SIG_KEY_SETTINGS_KEY = 'pemSignatureKey';
 	public const PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY = 'pemSignatureKeyExpiresAt';
-	public const PEM_SIG_KEY_EXPIRES_IN_SECONDS = 60 * 2;
+	public const PEM_SIG_KEY_EXPIRES_IN_SECONDS = 60 * 60;
 
 	public const PEM_ENC_KEY_SETTINGS_KEY = 'pemEncryptionKey';
 	public const PEM_ENC_KEY_EXPIRES_AT_SETTINGS_KEY = 'pemEncryptionKeyExpiresAt';
-	public const PEM_ENC_KEY_EXPIRES_IN_SECONDS = 60 * 2;
+	public const PEM_ENC_KEY_EXPIRES_IN_SECONDS = 60 * 60;
 
 	public function __construct(
 		private IAppConfig $appConfig,
@@ -105,6 +105,7 @@ public function generatePemPrivateKey(): string {
 	 * @throws AppConfigTypeConflictException
 	 */
 	public function getJwks(): array {
+		// we don't refresh here to make sure the IdP will get the key that was used to sign the client assertion
 		$myPemSignatureKey = $this->getMyPemSignatureKey(false);
 		$sslSignatureKey = openssl_pkey_get_private($myPemSignatureKey);
 		$sslSignatureKeyDetails = openssl_pkey_get_details($sslSignatureKey);
@@ -166,6 +167,7 @@ public function createJwt(array $payload, \OpenSSLAsymmetricKey $key, string $ke
 	}
 
 	public function generateClientAssertion(Provider $provider, string $discoveryIssuer, ?string $code = null): string {
+		// we refresh (if needed) here to make sure we use a key that will be served to the IdP in a few seconds
 		$myPemPrivateKey = $this->getMyPemSignatureKey();
 		$sslPrivateKey = openssl_pkey_get_private($myPemPrivateKey);
 		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);

From 94920d53b344c89448a9fecb61deedd53cb174a6 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Tue, 4 Nov 2025 17:16:58 +0100
Subject: [PATCH 10/25] implement small signature key tests

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 lib/Controller/ApiController.php      |  4 +-
 tests/unit/Service/JwkServiceTest.php | 68 +++++++++++++++++++++++++++
 2 files changed, 70 insertions(+), 2 deletions(-)
 create mode 100644 tests/unit/Service/JwkServiceTest.php

diff --git a/lib/Controller/ApiController.php b/lib/Controller/ApiController.php
index c4c15313..fe0e62a9 100644
--- a/lib/Controller/ApiController.php
+++ b/lib/Controller/ApiController.php
@@ -92,8 +92,8 @@ public function deleteUser(string $userId): DataResponse {
 	public function getJwks(): JSONResponse {
 		try {
 			$jwks = $this->jwkService->getJwks();
-			return new JSONResponse(['keys' => $jwks]);
-			// return new JSONResponse($this->jwkService->debug());
+//			return new JSONResponse(['keys' => $jwks]);
+			 return new JSONResponse($this->jwkService->debug());
 		} catch (\Exception|\Throwable $e) {
 			return new JSONResponse(['error' => $e->getMessage()], Http::STATUS_INTERNAL_SERVER_ERROR);
 		}
diff --git a/tests/unit/Service/JwkServiceTest.php b/tests/unit/Service/JwkServiceTest.php
new file mode 100644
index 00000000..4f600200
--- /dev/null
+++ b/tests/unit/Service/JwkServiceTest.php
@@ -0,0 +1,68 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+declare(strict_types=1);
+
+
+use OCA\UserOIDC\Service\JwkService;
+use OCA\UserOIDC\Vendor\Firebase\JWT\JWK;
+use OCA\UserOIDC\Vendor\Firebase\JWT\JWT;
+use OCP\AppFramework\Services\IAppConfig;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+
+class JwkServiceTest extends TestCase {
+
+	/** @var IAppConfig|MockObject */
+	private $appConfig;
+	/** @var JwkService|MockObject */
+	private $jwkService;
+
+	public function setUp(): void {
+		parent::setUp();
+		$this->appConfig = $this->createMock(IAppConfig::class);
+		$this->jwkService = new JwkService($this->appConfig);
+	}
+
+	public function testSignatureKeyAndJwt() {
+		$myPemPrivateKey = $this->jwkService->getMyPemSignatureKey();
+		$sslPrivateKey = openssl_pkey_get_private($myPemPrivateKey);
+		$pubKey = openssl_pkey_get_details($sslPrivateKey);
+		$pubKeyPem = $pubKey['key'];
+		$this->assertStringContainsString('-----BEGIN PUBLIC KEY-----', $pubKeyPem);
+		$this->assertStringContainsString('-----END PUBLIC KEY-----', $pubKeyPem);
+		$this->assertStringContainsString('-----BEGIN PRIVATE KEY-----', $myPemPrivateKey);
+		$this->assertStringContainsString('-----END PRIVATE KEY-----', $myPemPrivateKey);
+
+		$initialPayload = ['nice' => 'example'];
+		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(JwkService::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
+		$jwkId = 'sig_key_' . $pemPrivateKeyExpiresAt;
+		$signedJwtToken = $this->jwkService->createJwt($initialPayload, $sslPrivateKey, $jwkId, 'ES384');
+
+		// check JWK
+		$jwk = $this->jwkService->getJwkFromSslKey($pubKey);
+		$this->assertEquals('EC', $jwk['kty']);
+		$this->assertEquals('sig', $jwk['use']);
+		$this->assertEquals($jwkId, $jwk['kid']);
+		$this->assertEquals('P-384', $jwk['crv']);
+		$this->assertEquals('ES384', $jwk['alg']);
+
+		// check content of JWT
+		$rawJwks = ['keys' => [$jwk]];
+		$jwks = JWK::parseKeySet($rawJwks, 'ES384');
+		$jwtPayload = JWT::decode($signedJwtToken, $jwks);
+		$jwtPayloadArray = json_decode(json_encode($jwtPayload), true);
+		$this->assertEquals($initialPayload, $jwtPayloadArray);
+
+		// check header of JWT
+		$jwtParts = explode('.', $signedJwtToken, 3);
+		$jwtHeader = json_decode(JWT::urlsafeB64Decode($jwtParts[0]), true);
+		$this->assertEquals('JWT', $jwtHeader['typ']);
+		$this->assertEquals('ES384', $jwtHeader['alg']);
+		$this->assertEquals($jwkId, $jwtHeader['kid']);
+	}
+}

From a272ab54d51369ab54c32067a5659f720a2ee719 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Tue, 4 Nov 2025 17:35:26 +0100
Subject: [PATCH 11/25] implement small encryption key tests

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 lib/Controller/ApiController.php      |  4 ++--
 lib/Service/JwkService.php            | 14 +++++++++-----
 tests/unit/Service/JwkServiceTest.php | 26 +++++++++++++++++++++-----
 3 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/lib/Controller/ApiController.php b/lib/Controller/ApiController.php
index fe0e62a9..c4c15313 100644
--- a/lib/Controller/ApiController.php
+++ b/lib/Controller/ApiController.php
@@ -92,8 +92,8 @@ public function deleteUser(string $userId): DataResponse {
 	public function getJwks(): JSONResponse {
 		try {
 			$jwks = $this->jwkService->getJwks();
-//			return new JSONResponse(['keys' => $jwks]);
-			 return new JSONResponse($this->jwkService->debug());
+			return new JSONResponse(['keys' => $jwks]);
+			// return new JSONResponse($this->jwkService->debug());
 		} catch (\Exception|\Throwable $e) {
 			return new JSONResponse(['error' => $e->getMessage()], Http::STATUS_INTERNAL_SERVER_ERROR);
 		}
diff --git a/lib/Service/JwkService.php b/lib/Service/JwkService.php
index 53aebeaf..47e1be65 100644
--- a/lib/Service/JwkService.php
+++ b/lib/Service/JwkService.php
@@ -23,10 +23,14 @@ class JwkService {
 	public const PEM_SIG_KEY_SETTINGS_KEY = 'pemSignatureKey';
 	public const PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY = 'pemSignatureKeyExpiresAt';
 	public const PEM_SIG_KEY_EXPIRES_IN_SECONDS = 60 * 60;
+	public const PEM_SIG_KEY_ALGORITHM = 'ES384';
+	public const PEM_SIG_KEY_CURVE = 'P-384';
 
 	public const PEM_ENC_KEY_SETTINGS_KEY = 'pemEncryptionKey';
 	public const PEM_ENC_KEY_EXPIRES_AT_SETTINGS_KEY = 'pemEncryptionKeyExpiresAt';
 	public const PEM_ENC_KEY_EXPIRES_IN_SECONDS = 60 * 60;
+	public const PEM_ENC_KEY_ALGORITHM = 'ECDH-ES+A192KW';
+	public const PEM_ENC_KEY_CURVE = 'P-384';
 
 	public function __construct(
 		private IAppConfig $appConfig,
@@ -127,10 +131,10 @@ public function getJwkFromSslKey(array $sslKeyDetails, bool $isEncryptionKey = f
 			'kty' => 'EC',
 			'use' => $isEncryptionKey ? 'enc' : 'sig',
 			'kid' => ($isEncryptionKey ? 'enc' : 'sig') . '_key_' . $pemPrivateKeyExpiresAt,
-			'crv' => 'P-384',
+			'crv' => $isEncryptionKey ? self::PEM_ENC_KEY_CURVE : self::PEM_SIG_KEY_CURVE,
 			'x' => \rtrim(\strtr(\base64_encode($sslKeyDetails['ec']['x']), '+/', '-_'), '='),
 			'y' => \rtrim(\strtr(\base64_encode($sslKeyDetails['ec']['y']), '+/', '-_'), '='),
-			'alg' => $isEncryptionKey ? 'ECDH-ES+A192KW' : 'ES384',
+			'alg' => $isEncryptionKey ? self::PEM_ENC_KEY_ALGORITHM : self::PEM_SIG_KEY_ALGORITHM,
 		];
 		return $jwk;
 	}
@@ -185,7 +189,7 @@ public function generateClientAssertion(Provider $provider, string $discoveryIss
 			$payload['code'] = $code;
 		}
 
-		return $this->createJwt($payload, $sslPrivateKey, 'sig_key_' . $pemPrivateKeyExpiresAt, 'ES384');
+		return $this->createJwt($payload, $sslPrivateKey, 'sig_key_' . $pemPrivateKeyExpiresAt, self::PEM_SIG_KEY_ALGORITHM);
 	}
 
 	public function debug(): array {
@@ -196,11 +200,11 @@ public function debug(): array {
 
 		$payload = ['lll' => 'aaa'];
 		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
-		$signedJwtToken = $this->createJwt($payload, $sslPrivateKey, 'sig_key_' . $pemPrivateKeyExpiresAt, 'ES384');
+		$signedJwtToken = $this->createJwt($payload, $sslPrivateKey, 'sig_key_' . $pemPrivateKeyExpiresAt, self::PEM_SIG_KEY_ALGORITHM);
 
 		// check content of JWT
 		$rawJwks = ['keys' => [$this->getJwkFromSslKey($pubKey)]];
-		$jwks = JWK::parseKeySet($rawJwks, 'ES384');
+		$jwks = JWK::parseKeySet($rawJwks, self::PEM_SIG_KEY_ALGORITHM);
 		$jwtPayload = JWT::decode($signedJwtToken, $jwks);
 		$jwtPayloadArray = json_decode(json_encode($jwtPayload), true);
 
diff --git a/tests/unit/Service/JwkServiceTest.php b/tests/unit/Service/JwkServiceTest.php
index 4f600200..98b7350f 100644
--- a/tests/unit/Service/JwkServiceTest.php
+++ b/tests/unit/Service/JwkServiceTest.php
@@ -41,19 +41,19 @@ public function testSignatureKeyAndJwt() {
 		$initialPayload = ['nice' => 'example'];
 		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(JwkService::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
 		$jwkId = 'sig_key_' . $pemPrivateKeyExpiresAt;
-		$signedJwtToken = $this->jwkService->createJwt($initialPayload, $sslPrivateKey, $jwkId, 'ES384');
+		$signedJwtToken = $this->jwkService->createJwt($initialPayload, $sslPrivateKey, $jwkId, JwkService::PEM_SIG_KEY_ALGORITHM);
 
 		// check JWK
 		$jwk = $this->jwkService->getJwkFromSslKey($pubKey);
 		$this->assertEquals('EC', $jwk['kty']);
 		$this->assertEquals('sig', $jwk['use']);
 		$this->assertEquals($jwkId, $jwk['kid']);
-		$this->assertEquals('P-384', $jwk['crv']);
-		$this->assertEquals('ES384', $jwk['alg']);
+		$this->assertEquals(JwkService::PEM_SIG_KEY_CURVE, $jwk['crv']);
+		$this->assertEquals(JwkService::PEM_SIG_KEY_ALGORITHM, $jwk['alg']);
 
 		// check content of JWT
 		$rawJwks = ['keys' => [$jwk]];
-		$jwks = JWK::parseKeySet($rawJwks, 'ES384');
+		$jwks = JWK::parseKeySet($rawJwks, JwkService::PEM_SIG_KEY_ALGORITHM);
 		$jwtPayload = JWT::decode($signedJwtToken, $jwks);
 		$jwtPayloadArray = json_decode(json_encode($jwtPayload), true);
 		$this->assertEquals($initialPayload, $jwtPayloadArray);
@@ -62,7 +62,23 @@ public function testSignatureKeyAndJwt() {
 		$jwtParts = explode('.', $signedJwtToken, 3);
 		$jwtHeader = json_decode(JWT::urlsafeB64Decode($jwtParts[0]), true);
 		$this->assertEquals('JWT', $jwtHeader['typ']);
-		$this->assertEquals('ES384', $jwtHeader['alg']);
+		$this->assertEquals(JwkService::PEM_SIG_KEY_ALGORITHM, $jwtHeader['alg']);
 		$this->assertEquals($jwkId, $jwtHeader['kid']);
 	}
+
+	public function testEncryptionKey() {
+		$myPemEncryptionKey = $this->jwkService->getMyEncryptionKey();
+		$sslEncryptionKey = openssl_pkey_get_private($myPemEncryptionKey);
+		$sslEncryptionKeyDetails = openssl_pkey_get_details($sslEncryptionKey);
+		$encJwk = $this->jwkService->getJwkFromSslKey($sslEncryptionKeyDetails, isEncryptionKey: true);
+
+		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(JwkService::PEM_ENC_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
+		$encJwkId = 'enc_key_' . $pemPrivateKeyExpiresAt;
+
+		$this->assertEquals('EC', $encJwk['kty']);
+		$this->assertEquals('enc', $encJwk['use']);
+		$this->assertEquals($encJwkId, $encJwk['kid']);
+		$this->assertEquals(JwkService::PEM_ENC_KEY_CURVE, $encJwk['crv']);
+		$this->assertEquals(JwkService::PEM_ENC_KEY_ALGORITHM, $encJwk['alg']);
+	}
 }

From b2b1dbb60db15de9577f1cf485fd5a77db74e4da Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Thu, 6 Nov 2025 16:10:30 +0100
Subject: [PATCH 12/25] implement JWE encryption + decryption with algos
 working with singpass

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 appinfo/routes.php               |   2 +
 composer.json                    |   3 +-
 composer.lock                    | 422 +++++++++++++++++++++++++------
 lib/Controller/ApiController.php |  23 +-
 lib/Service/JweService.php       | 181 +++++++++++++
 lib/Service/JwkService.php       |  56 +---
 6 files changed, 563 insertions(+), 124 deletions(-)
 create mode 100644 lib/Service/JweService.php

diff --git a/appinfo/routes.php b/appinfo/routes.php
index 05584c8e..732b58a1 100644
--- a/appinfo/routes.php
+++ b/appinfo/routes.php
@@ -20,6 +20,8 @@
 		['name' => 'api#createUser', 'url' => '/user', 'verb' => 'POST'],
 		['name' => 'api#deleteUser', 'url' => '/user/{userId}', 'verb' => 'DELETE'],
 		['name' => 'api#getJwks', 'url' => '/jwks', 'verb' => 'GET'],
+		['name' => 'api#debugJwk', 'url' => '/debug-jwk', 'verb' => 'GET'],
+		['name' => 'api#debugJwe', 'url' => '/debug-jwe', 'verb' => 'GET'],
 
 		['name' => 'id4me#showLogin', 'url' => '/id4me', 'verb' => 'GET'],
 		['name' => 'id4me#login', 'url' => '/id4me', 'verb' => 'POST'],
diff --git a/composer.json b/composer.json
index 287c3905..4bf8ad1a 100644
--- a/composer.json
+++ b/composer.json
@@ -33,7 +33,8 @@
     "id4me/id4me-rp": "^1.2",
     "firebase/php-jwt": "^7",
     "bamarni/composer-bin-plugin": "^1.4",
-    "strobotti/php-jwk": "^1.3"
+    "web-token/jwt-library": "^4.1",
+    "spomky-labs/aes-key-wrap": "^7.0"
   },
   "require-dev": {
     "nextcloud/coding-standard": "^1.0.0",
diff --git a/composer.lock b/composer.lock
index a1dc04f1..caa890e6 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "2c4f937df9960ebd989efe94d706e93b",
+    "content-hash": "326ae587745b1643b94c392a3e82acf3",
     "packages": [
         {
             "name": "bamarni/composer-bin-plugin",
@@ -63,6 +63,66 @@
             },
             "time": "2026-02-04T10:18:12+00:00"
         },
+        {
+            "name": "brick/math",
+            "version": "0.14.8",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/brick/math.git",
+                "reference": "63422359a44b7f06cae63c3b429b59e8efcc0629"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/brick/math/zipball/63422359a44b7f06cae63c3b429b59e8efcc0629",
+                "reference": "63422359a44b7f06cae63c3b429b59e8efcc0629",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^8.2"
+            },
+            "require-dev": {
+                "php-coveralls/php-coveralls": "^2.2",
+                "phpstan/phpstan": "2.1.22",
+                "phpunit/phpunit": "^11.5"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Brick\\Math\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "description": "Arbitrary-precision arithmetic library",
+            "keywords": [
+                "Arbitrary-precision",
+                "BigInteger",
+                "BigRational",
+                "arithmetic",
+                "bigdecimal",
+                "bignum",
+                "bignumber",
+                "brick",
+                "decimal",
+                "integer",
+                "math",
+                "mathematics",
+                "rational"
+            ],
+            "support": {
+                "issues": "https://github.com/brick/math/issues",
+                "source": "https://github.com/brick/math/tree/0.14.8"
+            },
+            "funding": [
+                {
+                    "url": "https://github.com/BenMorel",
+                    "type": "github"
+                }
+            ],
+            "time": "2026-02-10T14:33:43+00:00"
+        },
         {
             "name": "firebase/php-jwt",
             "version": "v7.0.3",
@@ -282,33 +342,88 @@
             "time": "2026-03-19T02:54:44+00:00"
         },
         {
-            "name": "strobotti/php-jwk",
-            "version": "v1.3.0",
+            "name": "psr/clock",
+            "version": "1.0.0",
             "source": {
                 "type": "git",
-                "url": "https://github.com/Strobotti/php-jwk.git",
-                "reference": "a78580b55380f25bd8110452a5a031e36043551e"
+                "url": "https://github.com/php-fig/clock.git",
+                "reference": "e41a24703d4560fd0acb709162f73b8adfc3aa0d"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/Strobotti/php-jwk/zipball/a78580b55380f25bd8110452a5a031e36043551e",
-                "reference": "a78580b55380f25bd8110452a5a031e36043551e",
+                "url": "https://api.github.com/repos/php-fig/clock/zipball/e41a24703d4560fd0acb709162f73b8adfc3aa0d",
+                "reference": "e41a24703d4560fd0acb709162f73b8adfc3aa0d",
                 "shasum": ""
             },
             "require": {
-                "ext-json": "*",
+                "php": "^7.0 || ^8.0"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Psr\\Clock\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "https://www.php-fig.org/"
+                }
+            ],
+            "description": "Common interface for reading the clock.",
+            "homepage": "https://github.com/php-fig/clock",
+            "keywords": [
+                "clock",
+                "now",
+                "psr",
+                "psr-20",
+                "time"
+            ],
+            "support": {
+                "issues": "https://github.com/php-fig/clock/issues",
+                "source": "https://github.com/php-fig/clock/tree/1.0.0"
+            },
+            "time": "2022-11-25T14:36:26+00:00"
+        },
+        {
+            "name": "spomky-labs/aes-key-wrap",
+            "version": "v7.0.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/Spomky-Labs/aes-key-wrap.git",
+                "reference": "fbeb834b1f83aa8fbdfbd4c12124f71d4c1606ae"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/Spomky-Labs/aes-key-wrap/zipball/fbeb834b1f83aa8fbdfbd4c12124f71d4c1606ae",
+                "reference": "fbeb834b1f83aa8fbdfbd4c12124f71d4c1606ae",
+                "shasum": ""
+            },
+            "require": {
+                "ext-mbstring": "*",
                 "ext-openssl": "*",
-                "php": ">=7.2.0",
-                "phpseclib/phpseclib": "^2.0"
+                "php": ">=8.0"
             },
             "require-dev": {
-                "friendsofphp/php-cs-fixer": "^2.16",
-                "phpunit/phpunit": "^8.0"
+                "infection/infection": "^0.25.4",
+                "phpstan/extension-installer": "^1.1",
+                "phpstan/phpstan": "^1.0",
+                "phpstan/phpstan-beberlei-assert": "^1.0",
+                "phpstan/phpstan-deprecation-rules": "^1.0",
+                "phpstan/phpstan-phpunit": "^1.0",
+                "phpstan/phpstan-strict-rules": "^1.0",
+                "phpunit/phpunit": "^9.0",
+                "rector/rector": "^0.12.5",
+                "symplify/easy-coding-standard": "^10.0"
             },
             "type": "library",
             "autoload": {
                 "psr-4": {
-                    "Strobotti\\JWK\\": "src/"
+                    "AESKW\\": "src/"
                 }
             },
             "notification-url": "https://packagist.org/downloads/",
@@ -317,23 +432,236 @@
             ],
             "authors": [
                 {
-                    "name": "Juha Jantunen",
-                    "email": "juha@strobotti.com",
-                    "homepage": "https://www.strobotti.com",
-                    "role": "Developer"
+                    "name": "Florent Morselli",
+                    "homepage": "https://github.com/Spomky-Labs/aes-key-wrap/contributors"
                 }
             ],
-            "description": "A small PHP library to handle JWKs (Json Web Keys)",
-            "homepage": "https://github.com/Strobotti/php-jwk",
+            "description": "AES Key Wrap for PHP.",
+            "homepage": "https://github.com/Spomky-Labs/aes-key-wrap",
             "keywords": [
+                "A128KW",
+                "A192KW",
+                "A256KW",
+                "RFC3394",
+                "RFC5649",
+                "aes",
+                "key",
+                "padding",
+                "wrap"
+            ],
+            "support": {
+                "issues": "https://github.com/Spomky-Labs/aes-key-wrap/issues",
+                "source": "https://github.com/Spomky-Labs/aes-key-wrap/tree/v7.0.0"
+            },
+            "funding": [
+                {
+                    "url": "https://github.com/Spomky",
+                    "type": "github"
+                },
+                {
+                    "url": "https://www.patreon.com/FlorentMorselli",
+                    "type": "patreon"
+                }
+            ],
+            "time": "2021-12-08T20:36:59+00:00"
+        },
+        {
+            "name": "spomky-labs/pki-framework",
+            "version": "1.4.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/Spomky-Labs/pki-framework.git",
+                "reference": "f0e9a548df4e3942886adc9b7830581a46334631"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/Spomky-Labs/pki-framework/zipball/f0e9a548df4e3942886adc9b7830581a46334631",
+                "reference": "f0e9a548df4e3942886adc9b7830581a46334631",
+                "shasum": ""
+            },
+            "require": {
+                "brick/math": "^0.10|^0.11|^0.12|^0.13|^0.14",
+                "ext-mbstring": "*",
+                "php": ">=8.1"
+            },
+            "require-dev": {
+                "ekino/phpstan-banned-code": "^1.0|^2.0|^3.0",
+                "ext-gmp": "*",
+                "ext-openssl": "*",
+                "infection/infection": "^0.28|^0.29|^0.31",
+                "php-parallel-lint/php-parallel-lint": "^1.3",
+                "phpstan/extension-installer": "^1.3|^2.0",
+                "phpstan/phpstan": "^1.8|^2.0",
+                "phpstan/phpstan-deprecation-rules": "^1.0|^2.0",
+                "phpstan/phpstan-phpunit": "^1.1|^2.0",
+                "phpstan/phpstan-strict-rules": "^1.3|^2.0",
+                "phpunit/phpunit": "^10.1|^11.0|^12.0",
+                "rector/rector": "^1.0|^2.0",
+                "roave/security-advisories": "dev-latest",
+                "symfony/string": "^6.4|^7.0|^8.0",
+                "symfony/var-dumper": "^6.4|^7.0|^8.0",
+                "symplify/easy-coding-standard": "^12.0"
+            },
+            "suggest": {
+                "ext-bcmath": "For better performance (or GMP)",
+                "ext-gmp": "For better performance (or BCMath)",
+                "ext-openssl": "For OpenSSL based cyphering"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "SpomkyLabs\\Pki\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Joni Eskelinen",
+                    "email": "jonieske@gmail.com",
+                    "role": "Original developer"
+                },
+                {
+                    "name": "Florent Morselli",
+                    "email": "florent.morselli@spomky-labs.com",
+                    "role": "Spomky-Labs PKI Framework developer"
+                }
+            ],
+            "description": "A PHP framework for managing Public Key Infrastructures. It comprises X.509 public key certificates, attribute certificates, certification requests and certification path validation.",
+            "homepage": "https://github.com/spomky-labs/pki-framework",
+            "keywords": [
+                "DER",
+                "Private Key",
+                "ac",
+                "algorithm identifier",
+                "asn.1",
+                "asn1",
+                "attribute certificate",
+                "certificate",
+                "certification request",
+                "cryptography",
+                "csr",
+                "decrypt",
+                "ec",
+                "encrypt",
+                "pem",
+                "pkcs",
+                "public key",
+                "rsa",
+                "sign",
+                "signature",
+                "verify",
+                "x.509",
+                "x.690",
+                "x509",
+                "x690"
+            ],
+            "support": {
+                "issues": "https://github.com/Spomky-Labs/pki-framework/issues",
+                "source": "https://github.com/Spomky-Labs/pki-framework/tree/1.4.1"
+            },
+            "funding": [
+                {
+                    "url": "https://github.com/Spomky",
+                    "type": "github"
+                },
+                {
+                    "url": "https://www.patreon.com/FlorentMorselli",
+                    "type": "patreon"
+                }
+            ],
+            "time": "2025-12-20T12:57:40+00:00"
+        },
+        {
+            "name": "web-token/jwt-library",
+            "version": "4.1.3",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/web-token/jwt-library.git",
+                "reference": "690d4dd47b78f423cb90457f858e4106e1deb728"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/web-token/jwt-library/zipball/690d4dd47b78f423cb90457f858e4106e1deb728",
+                "reference": "690d4dd47b78f423cb90457f858e4106e1deb728",
+                "shasum": ""
+            },
+            "require": {
+                "brick/math": "^0.12|^0.13|^0.14",
+                "php": ">=8.2",
+                "psr/clock": "^1.0",
+                "spomky-labs/pki-framework": "^1.2.1"
+            },
+            "conflict": {
+                "spomky-labs/jose": "*"
+            },
+            "suggest": {
+                "ext-bcmath": "GMP or BCMath is highly recommended to improve the library performance",
+                "ext-gmp": "GMP or BCMath is highly recommended to improve the library performance",
+                "ext-openssl": "For key management (creation, optimization, etc.) and some algorithms (AES, RSA, ECDSA, etc.)",
+                "ext-sodium": "Sodium is required for OKP key creation, EdDSA signature algorithm and ECDH-ES key encryption with OKP keys",
+                "paragonie/sodium_compat": "Sodium is required for OKP key creation, EdDSA signature algorithm and ECDH-ES key encryption with OKP keys",
+                "spomky-labs/aes-key-wrap": "For all Key Wrapping algorithms (AxxxKW, AxxxGCMKW, PBES2-HSxxx+AyyyKW...)",
+                "symfony/console": "Needed to use console commands",
+                "symfony/http-client": "To enable JKU/X5U support."
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Jose\\Component\\": ""
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Florent Morselli",
+                    "homepage": "https://github.com/Spomky"
+                },
+                {
+                    "name": "All contributors",
+                    "homepage": "https://github.com/web-token/jwt-framework/contributors"
+                }
+            ],
+            "description": "JWT library",
+            "homepage": "https://github.com/web-token",
+            "keywords": [
+                "JOSE",
+                "JWE",
                 "JWK",
-                "JWKS"
+                "JWKSet",
+                "JWS",
+                "Jot",
+                "RFC7515",
+                "RFC7516",
+                "RFC7517",
+                "RFC7518",
+                "RFC7519",
+                "RFC7520",
+                "bundle",
+                "jwa",
+                "jwt",
+                "symfony"
             ],
             "support": {
-                "issues": "https://github.com/Strobotti/php-jwk/issues",
-                "source": "https://github.com/Strobotti/php-jwk/tree/master"
+                "issues": "https://github.com/web-token/jwt-library/issues",
+                "source": "https://github.com/web-token/jwt-library/tree/4.1.3"
             },
-            "time": "2020-04-01T03:22:04+00:00"
+            "funding": [
+                {
+                    "url": "https://github.com/Spomky",
+                    "type": "github"
+                },
+                {
+                    "url": "https://www.patreon.com/FlorentMorselli",
+                    "type": "patreon"
+                }
+            ],
+            "time": "2025-12-18T14:27:35+00:00"
         }
     ],
     "packages-dev": [
@@ -1390,54 +1718,6 @@
             ],
             "time": "2026-02-18T12:37:06+00:00"
         },
-        {
-            "name": "psr/clock",
-            "version": "1.0.0",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/php-fig/clock.git",
-                "reference": "e41a24703d4560fd0acb709162f73b8adfc3aa0d"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/php-fig/clock/zipball/e41a24703d4560fd0acb709162f73b8adfc3aa0d",
-                "reference": "e41a24703d4560fd0acb709162f73b8adfc3aa0d",
-                "shasum": ""
-            },
-            "require": {
-                "php": "^7.0 || ^8.0"
-            },
-            "type": "library",
-            "autoload": {
-                "psr-4": {
-                    "Psr\\Clock\\": "src/"
-                }
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "MIT"
-            ],
-            "authors": [
-                {
-                    "name": "PHP-FIG",
-                    "homepage": "https://www.php-fig.org/"
-                }
-            ],
-            "description": "Common interface for reading the clock.",
-            "homepage": "https://github.com/php-fig/clock",
-            "keywords": [
-                "clock",
-                "now",
-                "psr",
-                "psr-20",
-                "time"
-            ],
-            "support": {
-                "issues": "https://github.com/php-fig/clock/issues",
-                "source": "https://github.com/php-fig/clock/tree/1.0.0"
-            },
-            "time": "2022-11-25T14:36:26+00:00"
-        },
         {
             "name": "psr/container",
             "version": "2.0.2",
diff --git a/lib/Controller/ApiController.php b/lib/Controller/ApiController.php
index c4c15313..f51e653c 100644
--- a/lib/Controller/ApiController.php
+++ b/lib/Controller/ApiController.php
@@ -11,6 +11,7 @@
 
 use OCA\UserOIDC\AppInfo\Application;
 use OCA\UserOIDC\Db\UserMapper;
+use OCA\UserOIDC\Service\JweService;
 use OCA\UserOIDC\Service\JwkService;
 use OCP\AppFramework\Controller;
 use OCP\AppFramework\Http;
@@ -33,6 +34,7 @@ public function __construct(
 		private UserMapper $userMapper,
 		private IUserManager $userManager,
 		private JwkService $jwkService,
+		private JweService $jweService,
 	) {
 		parent::__construct(Application::APP_ID, $request);
 	}
@@ -93,7 +95,26 @@ public function getJwks(): JSONResponse {
 		try {
 			$jwks = $this->jwkService->getJwks();
 			return new JSONResponse(['keys' => $jwks]);
-			// return new JSONResponse($this->jwkService->debug());
+		} catch (\Exception|\Throwable $e) {
+			return new JSONResponse(['error' => $e->getMessage()], Http::STATUS_INTERNAL_SERVER_ERROR);
+		}
+	}
+
+	#[NoCSRFRequired]
+	#[PublicPage]
+	public function debugJwk(): JSONResponse {
+		try {
+			return new JSONResponse($this->jwkService->debug());
+		} catch (\Exception|\Throwable $e) {
+			return new JSONResponse(['error' => $e->getMessage()], Http::STATUS_INTERNAL_SERVER_ERROR);
+		}
+	}
+
+	#[NoCSRFRequired]
+	#[PublicPage]
+	public function debugJwe(): JSONResponse {
+		try {
+			return new JSONResponse($this->jweService->debug());
 		} catch (\Exception|\Throwable $e) {
 			return new JSONResponse(['error' => $e->getMessage()], Http::STATUS_INTERNAL_SERVER_ERROR);
 		}
diff --git a/lib/Service/JweService.php b/lib/Service/JweService.php
new file mode 100644
index 00000000..bca4a5b9
--- /dev/null
+++ b/lib/Service/JweService.php
@@ -0,0 +1,181 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\UserOIDC\Service;
+
+require_once __DIR__ . '/../../vendor/autoload.php';
+
+use Jose\Component\Checker\AlgorithmChecker;
+use Jose\Component\Checker\HeaderCheckerManager;
+use Jose\Component\Core\AlgorithmManager;
+use Jose\Component\Core\JWK;
+use Jose\Component\Encryption\Algorithm\ContentEncryption\A192CBCHS384;
+use Jose\Component\Encryption\Algorithm\ContentEncryption\A256CBCHS512;
+use Jose\Component\Encryption\Algorithm\KeyEncryption\A256KW;
+use Jose\Component\Encryption\Algorithm\KeyEncryption\ECDHESA192KW;
+use Jose\Component\Encryption\JWEBuilder;
+use Jose\Component\Encryption\JWEDecrypter;
+use Jose\Component\Encryption\JWELoader;
+use Jose\Component\Encryption\JWETokenSupport;
+use Jose\Component\Encryption\Serializer\CompactSerializer;
+use Jose\Component\Encryption\Serializer\JWESerializerManager;
+
+class JweService {
+
+	public function __construct(
+		private JwkService $jwkService,
+	) {
+	}
+
+	public function createSerializedJwe(array $payloadArray, array $encryptionJwk): string {
+		// encrypt a JWT payload with the enc key => JWE
+
+		$algorithmManager = new AlgorithmManager([
+			new A256KW(),
+			new A256CBCHS512(),
+			new ECDHESA192KW(),
+			new A192CBCHS384(),
+		]);
+
+		// The compression method manager with the DEF (Deflate) method.
+		//$compressionMethodManager = new CompressionMethodManager([
+		//    new Deflate(),
+		//]);
+
+		// We instantiate our JWE Builder.
+		$jweBuilder = new JWEBuilder(
+			$algorithmManager,
+		);
+
+		// Our key.
+		$jwk = new JWK($encryptionJwk);
+
+		// The payload we want to encrypt. It MUST be a string.
+		$payload = json_encode($payloadArray);
+
+		$jwe = $jweBuilder
+			->create()              // We want to create a new JWE
+			->withPayload($payload) // We set the payload
+			->withSharedProtectedHeader([
+				// Key Encryption Algorithm
+				// 'alg' => 'A256KW',
+				'alg' => 'ECDH-ES+A192KW',
+				// Content Encryption Algorithm
+				// 'enc' => 'A256CBC-HS512',
+				'enc' => 'A192CBC-HS384',
+				//'zip' => 'DEF'            // Not recommended.
+			])
+			->addRecipient($jwk)    // We add a recipient (a shared key or public key).
+			->build();
+
+		$serializer = new CompactSerializer(); // The serializer
+		return $serializer->serialize($jwe, 0); // We serialize the recipient at index 0 (we only have one recipient).
+	}
+
+	public function decryptSerializedJwe(string $serializedJwe, array $jwkArray): string {
+		$algorithmManager = new AlgorithmManager([
+			new A256KW(),
+			new A256CBCHS512(),
+			new ECDHESA192KW(),
+			new A192CBCHS384(),
+		]);
+
+		// The compression method manager with the DEF (Deflate) method.
+		//$compressionMethodManager = new CompressionMethodManager([
+		//    new Deflate(),
+		//]);
+
+		// We instantiate our JWE Decrypter.
+		$jweDecrypter = new JWEDecrypter(
+			$algorithmManager,
+		);
+
+		// Our key.
+		$jwk = new JWK($jwkArray);
+
+		// The serializer manager. We only use the JWE Compact Serialization Mode.
+		$serializerManager = new JWESerializerManager([
+			new CompactSerializer(),
+		]);
+
+		// ----------- OPTION 1
+		/*
+		// We try to load the token.
+		$jwe = $serializerManager->unserialize($serializedJwe);
+
+		// We decrypt the token. This method does NOT check the header.
+		$success = $jweDecrypter->decryptUsingKey($jwe, $jwk, 0);
+		*/
+
+		// ----------- OPTION 2
+		$headerCheckerManager = new HeaderCheckerManager(
+			// Provide the allowed algorithms using the previously created
+			// AlgorithmManager.
+			[
+				new AlgorithmChecker(
+					// $keyEncryptionAlgorithmManager->list()
+					$algorithmManager->list()
+				)
+			],
+			// Provide the appropriate TokenTypeSupport[].
+			[
+				new JWETokenSupport(),
+			]
+		);
+
+		// no idea why TooManyArguments is thrown by psalm
+		/** @psalm-suppress TooManyArguments */
+		$jweLoader = new JWELoader(
+			$serializerManager,
+			$jweDecrypter,
+			$headerCheckerManager,
+		);
+
+		$jwe = $jweLoader->loadAndDecryptWithKey($serializedJwe, $jwk, $recipient);
+		$payload = $jwe->getPayload();
+		if ($payload === null) {
+			throw new \Exception('Could not decrypt JWE, payload is null');
+		}
+
+		return $payload;
+	}
+
+	public function debug(): array {
+		// get encryption key, both formats
+		$myPemEncryptionKey = $this->jwkService->getMyEncryptionKey(true);
+		$sslEncryptionKey = openssl_pkey_get_private($myPemEncryptionKey);
+		$sslEncryptionKeyDetails = openssl_pkey_get_details($sslEncryptionKey);
+		$encPublicJwk = $this->jwkService->getJwkFromSslKey($sslEncryptionKeyDetails, isEncryptionKey: true);
+		$encPrivJwk = $this->jwkService->getJwkFromSslKey($sslEncryptionKeyDetails, isEncryptionKey: true, includePrivateKey: true);
+
+		$payloadArray = [
+			'iat' => time(),
+			'nbf' => time(),
+			'exp' => time() + 3600,
+			'iss' => 'My service',
+			'aud' => 'Your application',
+		];
+
+		/*
+		$exampleJwkArray = [
+			'kty' => 'oct',
+			'k' => 'dzI6nbW4OcNF-AtfxGAmuyz7IpHRudBI0WgGjZWgaRJt6prBn3DARXgUR8NVwKhfL43QBIU2Un3AvCGCHRgY4TbEqhOi8-i98xxmCggNjde4oaW6wkJ2NgM3Ss9SOX9zS3lcVzdCMdum-RwVJ301kbin4UtGztuzJBeg5oVN00MGxjC2xWwyI0tgXVs-zJs5WlafCuGfX1HrVkIf5bvpE0MQCSjdJpSeVao6-RSTYDajZf7T88a2eVjeW31mMAg-jzAWfUrii61T_bYPJFOXW8kkRWoa1InLRdG6bKB9wQs9-VdXZP60Q4Yuj_WZ-lO7qV9AEFrUkkjpaDgZT86w2g',
+		];
+		$serializedJweToken = $this->createSerializedJwe($payloadArray, $exampleJwkArray);
+		$decryptedJweString = $this->decryptSerializedJwe($serializedJweToken, $exampleJwkArray);
+		*/
+		$serializedJweToken = $this->createSerializedJwe($payloadArray, $encPublicJwk);
+		$decryptedJweString = $this->decryptSerializedJwe($serializedJweToken, $encPrivJwk);
+
+		return [
+			'input_payloadArray' => $payloadArray,
+			'input_serializedJweToken' => $serializedJweToken,
+			'output_payloadArray' => json_decode($decryptedJweString, true),
+		];
+	}
+}
diff --git a/lib/Service/JwkService.php b/lib/Service/JwkService.php
index 47e1be65..3ec3c199 100644
--- a/lib/Service/JwkService.php
+++ b/lib/Service/JwkService.php
@@ -2,7 +2,7 @@
 
 declare(strict_types=1);
 /**
- * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
  * SPDX-License-Identifier: AGPL-3.0-or-later
  */
 
@@ -15,8 +15,6 @@
 use OCA\UserOIDC\Vendor\Firebase\JWT\JWT;
 use OCP\AppFramework\Services\IAppConfig;
 use OCP\Exceptions\AppConfigTypeConflictException;
-use Strobotti\JWK\Key\KeyInterface;
-use Strobotti\JWK\KeyFactory;
 
 class JwkService {
 
@@ -121,11 +119,9 @@ public function getJwks(): array {
 			$this->getJwkFromSslKey($sslSignatureKeyDetails),
 			$this->getJwkFromSslKey($sslEncryptionKeyDetails, isEncryptionKey: true),
 		];
-		// $pubKeyPem = $sslPublicKey['key'];
-		// return $this->getJwkFromPem($pubKeyPem)->jsonSerialize();
 	}
 
-	public function getJwkFromSslKey(array $sslKeyDetails, bool $isEncryptionKey = false): array {
+	public function getJwkFromSslKey(array $sslKeyDetails, bool $isEncryptionKey = false, bool $includePrivateKey = false): array {
 		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
 		$jwk = [
 			'kty' => 'EC',
@@ -136,27 +132,12 @@ public function getJwkFromSslKey(array $sslKeyDetails, bool $isEncryptionKey = f
 			'y' => \rtrim(\strtr(\base64_encode($sslKeyDetails['ec']['y']), '+/', '-_'), '='),
 			'alg' => $isEncryptionKey ? self::PEM_ENC_KEY_ALGORITHM : self::PEM_SIG_KEY_ALGORITHM,
 		];
+		if ($includePrivateKey) {
+			$jwk['d'] = \rtrim(\strtr(\base64_encode($sslKeyDetails['ec']['d']), '+/', '-_'), '=');
+		}
 		return $jwk;
 	}
 
-	/**
-	 * Build a JWK from a PEM (public) key
-	 *
-	 * @param string $pemKey
-	 * @return KeyInterface
-	 * @throws AppConfigTypeConflictException
-	 */
-	public function getJwkFromPem(string $pemKey): KeyInterface {
-		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
-		$options = [
-			'use' => 'sig',
-			'alg' => 'RS512',
-			'kid' => 'sig_key_' . $pemPrivateKeyExpiresAt,
-		];
-		$keyFactory = new KeyFactory();
-		return $keyFactory->createFromPem($pemKey, $options);
-	}
-
 	/**
 	 * Create a JWT token signed with a given private SSL key
 	 *
@@ -223,31 +204,4 @@ public function debug(): array {
 			'arrays_are_equal' => $payload === $jwtPayloadArray,
 		];
 	}
-
-	public function debugRSA(): array {
-		$myPemPrivateKey = $this->getMyPemSignatureKey();
-		$sslPrivateKey = openssl_pkey_get_private($myPemPrivateKey);
-		$pubKey = openssl_pkey_get_details($sslPrivateKey);
-		$pubKeyPem = $pubKey['key'];
-
-		$payload = ['lll' => 'aaa'];
-		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
-		$signedJwtToken = $this->createJwt($payload, $sslPrivateKey, 'sig_key_' . $pemPrivateKeyExpiresAt);
-
-		// check content of JWT
-		$rawJwks = ['keys' => [$this->getJwkFromPem($pubKeyPem)->jsonSerialize()]];
-		$jwks = JWK::parseKeySet($rawJwks, 'RS512');
-		$jwtPayload = JWT::decode($signedJwtToken, $jwks);
-		$jwtPayloadArray = json_decode(json_encode($jwtPayload), true);
-
-		return [
-			'public_jwk' => $this->getJwkFromPem($pubKeyPem)->jsonSerialize(),
-			'public_pem' => $pubKeyPem,
-			'private_pem' => $myPemPrivateKey,
-			'payload' => $payload,
-			'signed_jwt' => $signedJwtToken,
-			'jwt_payload' => $jwtPayloadArray,
-			'arrays_are_equal' => $payload === $jwtPayloadArray,
-		];
-	}
 }

From dab8d055738f7ae2d7bb52293d7f81660dc4b63c Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Thu, 6 Nov 2025 16:18:27 +0100
Subject: [PATCH 13/25] implement JWE tests

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 lib/Service/JweService.php            |  1 -
 tests/unit/Service/JweServiceTest.php | 54 +++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)
 create mode 100644 tests/unit/Service/JweServiceTest.php

diff --git a/lib/Service/JweService.php b/lib/Service/JweService.php
index bca4a5b9..0301c2ce 100644
--- a/lib/Service/JweService.php
+++ b/lib/Service/JweService.php
@@ -146,7 +146,6 @@ public function decryptSerializedJwe(string $serializedJwe, array $jwkArray): st
 	}
 
 	public function debug(): array {
-		// get encryption key, both formats
 		$myPemEncryptionKey = $this->jwkService->getMyEncryptionKey(true);
 		$sslEncryptionKey = openssl_pkey_get_private($myPemEncryptionKey);
 		$sslEncryptionKeyDetails = openssl_pkey_get_details($sslEncryptionKey);
diff --git a/tests/unit/Service/JweServiceTest.php b/tests/unit/Service/JweServiceTest.php
new file mode 100644
index 00000000..d2d31546
--- /dev/null
+++ b/tests/unit/Service/JweServiceTest.php
@@ -0,0 +1,54 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+declare(strict_types=1);
+
+
+use OCA\UserOIDC\Service\JweService;
+use OCA\UserOIDC\Service\JwkService;
+use OCP\AppFramework\Services\IAppConfig;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+
+class JweServiceTest extends TestCase {
+
+	/** @var IAppConfig|MockObject */
+	private $appConfig;
+	/** @var JwkService|MockObject */
+	private $jwkService;
+	/** @var JweService|MockObject */
+	private $jweService;
+
+	public function setUp(): void {
+		parent::setUp();
+		$this->appConfig = $this->createMock(IAppConfig::class);
+		$this->jwkService = new JwkService($this->appConfig);
+		$this->jweService = new JweService($this->jwkService);
+	}
+
+	public function testJweEncryptionDecryption() {
+		$myPemEncryptionKey = $this->jwkService->getMyEncryptionKey(true);
+		$sslEncryptionKey = openssl_pkey_get_private($myPemEncryptionKey);
+		$sslEncryptionKeyDetails = openssl_pkey_get_details($sslEncryptionKey);
+		$encPublicJwk = $this->jwkService->getJwkFromSslKey($sslEncryptionKeyDetails, isEncryptionKey: true);
+		$encPrivJwk = $this->jwkService->getJwkFromSslKey($sslEncryptionKeyDetails, isEncryptionKey: true, includePrivateKey: true);
+
+		$inputPayloadArray = [
+			'iat' => time(),
+			'nbf' => time(),
+			'exp' => time() + 3600,
+			'iss' => 'My service',
+			'aud' => 'Your application',
+		];
+
+		$serializedJweToken = $this->jweService->createSerializedJwe($inputPayloadArray, $encPublicJwk);
+		$decryptedJweString = $this->jweService->decryptSerializedJwe($serializedJweToken, $encPrivJwk);
+
+		$outputPayloadArray = json_decode($decryptedJweString, true);
+		$this->assertEquals($inputPayloadArray, $outputPayloadArray);
+	}
+}

From ee26b13d898c66aae2f8ac4f1af3d91b0d6e0378 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Thu, 6 Nov 2025 18:00:39 +0100
Subject: [PATCH 14/25] polish

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 appinfo/info.xml           |  1 +
 lib/Service/JweService.php | 31 ++++++++++++++++++++++++-------
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/appinfo/info.xml b/appinfo/info.xml
index 354651ef..33557c4b 100644
--- a/appinfo/info.xml
+++ b/appinfo/info.xml
@@ -23,6 +23,7 @@
 	<bugs>https://github.com/nextcloud/user_oidc/issues</bugs>
 	<repository>https://github.com/nextcloud/user_oidc</repository>
 	<dependencies>
+		<php min-version="8.2"/>
 		<nextcloud min-version="29" max-version="34"/>
 	</dependencies>
 	<settings>
diff --git a/lib/Service/JweService.php b/lib/Service/JweService.php
index 0301c2ce..35801ae4 100644
--- a/lib/Service/JweService.php
+++ b/lib/Service/JweService.php
@@ -27,14 +27,25 @@
 
 class JweService {
 
+	public const CONTENT_ENCRYPTION_ALGORITHM = 'A192CBC-HS384';
+
 	public function __construct(
 		private JwkService $jwkService,
 	) {
 	}
 
-	public function createSerializedJwe(array $payloadArray, array $encryptionJwk): string {
-		// encrypt a JWT payload with the enc key => JWE
-
+	/**
+	 * @param array $payloadArray the content of the JWE
+	 * @param array $encryptionJwk the public key in JWK format
+	 * @param string $keyEncryptionAlg the algorithm to use for the key encryption
+	 * @param string $contentEncryptionAlg the algorithm to use for the content encryption
+	 * @return string
+	 */
+	public function createSerializedJwe(
+		array $payloadArray, array $encryptionJwk,
+		string $keyEncryptionAlg = JwkService::PEM_ENC_KEY_ALGORITHM,
+		string $contentEncryptionAlg = self::CONTENT_ENCRYPTION_ALGORITHM,
+	): string {
 		$algorithmManager = new AlgorithmManager([
 			new A256KW(),
 			new A256CBCHS512(),
@@ -64,10 +75,10 @@ public function createSerializedJwe(array $payloadArray, array $encryptionJwk):
 			->withSharedProtectedHeader([
 				// Key Encryption Algorithm
 				// 'alg' => 'A256KW',
-				'alg' => 'ECDH-ES+A192KW',
+				'alg' => $keyEncryptionAlg,
 				// Content Encryption Algorithm
 				// 'enc' => 'A256CBC-HS512',
-				'enc' => 'A192CBC-HS384',
+				'enc' => $contentEncryptionAlg,
 				//'zip' => 'DEF'            // Not recommended.
 			])
 			->addRecipient($jwk)    // We add a recipient (a shared key or public key).
@@ -77,6 +88,12 @@ public function createSerializedJwe(array $payloadArray, array $encryptionJwk):
 		return $serializer->serialize($jwe, 0); // We serialize the recipient at index 0 (we only have one recipient).
 	}
 
+	/**
+	 * @param string $serializedJwe the JWE token
+	 * @param array $jwkArray the private key in JWK format (with the 'd' attribute)
+	 * @return string
+	 * @throws \Exception
+	 */
 	public function decryptSerializedJwe(string $serializedJwe, array $jwkArray): string {
 		$algorithmManager = new AlgorithmManager([
 			new A256KW(),
@@ -119,8 +136,8 @@ public function decryptSerializedJwe(string $serializedJwe, array $jwkArray): st
 			[
 				new AlgorithmChecker(
 					// $keyEncryptionAlgorithmManager->list()
-					$algorithmManager->list()
-				)
+					$algorithmManager->list(),
+				),
 			],
 			// Provide the appropriate TokenTypeSupport[].
 			[

From 04950672253132e2ce62331a5dbbcf604417d954 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Wed, 19 Nov 2025 12:20:20 +0100
Subject: [PATCH 15/25] tests

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 lib/Controller/LoginController.php    | 20 +++++++++++++++++
 lib/Service/JweService.php            | 31 +++++++++++++++++++++++----
 tests/unit/Service/JweServiceTest.php |  4 ++--
 3 files changed, 49 insertions(+), 6 deletions(-)

diff --git a/lib/Controller/LoginController.php b/lib/Controller/LoginController.php
index f5fc9869..441d6ce0 100644
--- a/lib/Controller/LoginController.php
+++ b/lib/Controller/LoginController.php
@@ -21,6 +21,7 @@
 use OCA\UserOIDC\Event\TokenObtainedEvent;
 use OCA\UserOIDC\Helper\HttpClientHelper;
 use OCA\UserOIDC\Service\DiscoveryService;
+use OCA\UserOIDC\Service\JweService;
 use OCA\UserOIDC\Service\JwkService;
 use OCA\UserOIDC\Service\LdapService;
 use OCA\UserOIDC\Service\OIDCService;
@@ -103,6 +104,7 @@ public function __construct(
 		private OidcService $oidcService,
 		private ServerVersion $serverVersion,
 		private JwkService $jwkService,
+		private JweService $jweService,
 	) {
 		parent::__construct($request, $config, $l10n);
 	}
@@ -200,6 +202,8 @@ public function login(int $providerId, ?string $redirectUrl = null) {
 		$this->session->set(self::NONCE, $nonce);
 
 		$oidcSystemConfig = $this->config->getSystemValue('user_oidc', []);
+		// TODO add config param to force PKCE even if not supported in discovery
+		// condition becomes: ($isPkceSupported || $force) && ($oidcSystemConfig['use_pkce'] ?? true)
 		$isPkceSupported = in_array('S256', $discovery['code_challenge_methods_supported'] ?? [], true);
 		$isPkceEnabled = $isPkceSupported && ($oidcSystemConfig['use_pkce'] ?? true);
 
@@ -500,6 +504,22 @@ public function code(string $state = '', string $code = '', string $scope = '',
 
 		// TODO: proper error handling
 		$idTokenRaw = $data['id_token'];
+		if ($usePrivateKeyJwt) {
+			// we could check the header there
+			// if kid is our private JWK, we have a JWE to decrypt
+			// if typ=JWT, we have a classic JWT to decode
+			$jwtParts = explode('.', $idTokenRaw, 3);
+			$jwtHeader = json_decode(JWT::urlsafeB64Decode($jwtParts[0]), true);
+			$this->logger->warning('JWT HEADER', ['jwt_header' => $jwtHeader]);
+			if (isset($jwtHeader['typ']) && $jwtHeader['typ'] === 'JWT') {
+				// we have a JWT
+			} elseif (isset($jwtHeader['cty']) && $jwtHeader['cty'] === 'JWT') {
+				// we have a JWE
+			}
+
+			// $dec = $this->jweService->decryptSerializedJwe($idTokenRaw);
+			// $this->logger->warning('decrypted JWE', ['decrypted_jwe' => json_decode($dec, true)]);
+		}
 		$jwks = $this->discoveryService->obtainJWK($provider, $idTokenRaw);
 		JWT::$leeway = 60;
 		try {
diff --git a/lib/Service/JweService.php b/lib/Service/JweService.php
index 35801ae4..0e22f97b 100644
--- a/lib/Service/JweService.php
+++ b/lib/Service/JweService.php
@@ -41,7 +41,7 @@ public function __construct(
 	 * @param string $contentEncryptionAlg the algorithm to use for the content encryption
 	 * @return string
 	 */
-	public function createSerializedJwe(
+	public function createSerializedJweWithKey(
 		array $payloadArray, array $encryptionJwk,
 		string $keyEncryptionAlg = JwkService::PEM_ENC_KEY_ALGORITHM,
 		string $contentEncryptionAlg = self::CONTENT_ENCRYPTION_ALGORITHM,
@@ -94,7 +94,7 @@ public function createSerializedJwe(
 	 * @return string
 	 * @throws \Exception
 	 */
-	public function decryptSerializedJwe(string $serializedJwe, array $jwkArray): string {
+	public function decryptSerializedJweWithKey(string $serializedJwe, array $jwkArray): string {
 		$algorithmManager = new AlgorithmManager([
 			new A256KW(),
 			new A256CBCHS512(),
@@ -162,6 +162,24 @@ public function decryptSerializedJwe(string $serializedJwe, array $jwkArray): st
 		return $payload;
 	}
 
+	public function decryptSerializedJwe(string $serializedJwe): string {
+		$myPemEncryptionKey = $this->jwkService->getMyEncryptionKey(true);
+		$sslEncryptionKey = openssl_pkey_get_private($myPemEncryptionKey);
+		$sslEncryptionKeyDetails = openssl_pkey_get_details($sslEncryptionKey);
+		$encPrivJwk = $this->jwkService->getJwkFromSslKey($sslEncryptionKeyDetails, isEncryptionKey: true, includePrivateKey: true);
+
+		return $this->decryptSerializedJweWithKey($serializedJwe, $encPrivJwk);
+	}
+
+	public function createSerializedJwe(array $payloadArray): string {
+		$myPemEncryptionKey = $this->jwkService->getMyEncryptionKey(true);
+		$sslEncryptionKey = openssl_pkey_get_private($myPemEncryptionKey);
+		$sslEncryptionKeyDetails = openssl_pkey_get_details($sslEncryptionKey);
+		$encPublicJwk = $this->jwkService->getJwkFromSslKey($sslEncryptionKeyDetails, isEncryptionKey: true);
+
+		return $this->createSerializedJweWithKey($payloadArray, $encPublicJwk);
+	}
+
 	public function debug(): array {
 		$myPemEncryptionKey = $this->jwkService->getMyEncryptionKey(true);
 		$sslEncryptionKey = openssl_pkey_get_private($myPemEncryptionKey);
@@ -185,12 +203,17 @@ public function debug(): array {
 		$serializedJweToken = $this->createSerializedJwe($payloadArray, $exampleJwkArray);
 		$decryptedJweString = $this->decryptSerializedJwe($serializedJweToken, $exampleJwkArray);
 		*/
-		$serializedJweToken = $this->createSerializedJwe($payloadArray, $encPublicJwk);
-		$decryptedJweString = $this->decryptSerializedJwe($serializedJweToken, $encPrivJwk);
+		$serializedJweToken = $this->createSerializedJweWithKey($payloadArray, $encPublicJwk);
+		$jwtParts = explode('.', $serializedJweToken, 3);
+		$jwtHeader = json_decode(base64_decode($jwtParts[0]), true);
+		$decryptedJweString = $this->decryptSerializedJweWithKey($serializedJweToken, $encPrivJwk);
 
 		return [
+			'public_key' => $encPublicJwk,
+			'private_key' => $encPrivJwk,
 			'input_payloadArray' => $payloadArray,
 			'input_serializedJweToken' => $serializedJweToken,
+			'jwe_header' => $jwtHeader,
 			'output_payloadArray' => json_decode($decryptedJweString, true),
 		];
 	}
diff --git a/tests/unit/Service/JweServiceTest.php b/tests/unit/Service/JweServiceTest.php
index d2d31546..20473872 100644
--- a/tests/unit/Service/JweServiceTest.php
+++ b/tests/unit/Service/JweServiceTest.php
@@ -45,8 +45,8 @@ public function testJweEncryptionDecryption() {
 			'aud' => 'Your application',
 		];
 
-		$serializedJweToken = $this->jweService->createSerializedJwe($inputPayloadArray, $encPublicJwk);
-		$decryptedJweString = $this->jweService->decryptSerializedJwe($serializedJweToken, $encPrivJwk);
+		$serializedJweToken = $this->jweService->createSerializedJweWithKey($inputPayloadArray, $encPublicJwk);
+		$decryptedJweString = $this->jweService->decryptSerializedJweWithKey($serializedJweToken, $encPrivJwk);
 
 		$outputPayloadArray = json_decode($decryptedJweString, true);
 		$this->assertEquals($inputPayloadArray, $outputPayloadArray);

From ccce6e1e7c3d6ef6aad07a4124bd30f46595cb26 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Mon, 24 Nov 2025 15:27:44 +0100
Subject: [PATCH 16/25] last part: detect if a JWT is in a JWE on login

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 lib/Controller/LoginController.php    | 12 +++++++-----
 lib/Service/JweService.php            | 21 ++++++++++-----------
 tests/unit/Service/JweServiceTest.php |  3 ++-
 3 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/lib/Controller/LoginController.php b/lib/Controller/LoginController.php
index 441d6ce0..db5affe9 100644
--- a/lib/Controller/LoginController.php
+++ b/lib/Controller/LoginController.php
@@ -512,13 +512,15 @@ public function code(string $state = '', string $code = '', string $scope = '',
 			$jwtHeader = json_decode(JWT::urlsafeB64Decode($jwtParts[0]), true);
 			$this->logger->warning('JWT HEADER', ['jwt_header' => $jwtHeader]);
 			if (isset($jwtHeader['typ']) && $jwtHeader['typ'] === 'JWT') {
-				// we have a JWT
+				// we have a JWT, do nothing
 			} elseif (isset($jwtHeader['cty']) && $jwtHeader['cty'] === 'JWT') {
-				// we have a JWE
+				// we have a JWE that contains the JWT string (the ID token)
+				$idTokenRaw = $this->jweService->decryptSerializedJwe($idTokenRaw);
+				$this->logger->warning('raw decrypted JWE', ['decrypted_jwe' => $idTokenRaw]);
+				$this->logger->warning('decrypted+decoded JWE', ['decrypted_jwe' => json_decode($idTokenRaw, true)]);
+			} else {
+				$this->logger->warning('Unsupported id_token when using "private key JWT"', ['id_token' => $idTokenRaw]);
 			}
-
-			// $dec = $this->jweService->decryptSerializedJwe($idTokenRaw);
-			// $this->logger->warning('decrypted JWE', ['decrypted_jwe' => json_decode($dec, true)]);
 		}
 		$jwks = $this->discoveryService->obtainJWK($provider, $idTokenRaw);
 		JWT::$leeway = 60;
diff --git a/lib/Service/JweService.php b/lib/Service/JweService.php
index 0e22f97b..5aa2189f 100644
--- a/lib/Service/JweService.php
+++ b/lib/Service/JweService.php
@@ -35,14 +35,14 @@ public function __construct(
 	}
 
 	/**
-	 * @param array $payloadArray the content of the JWE
+	 * @param string $payload the content of the JWE
 	 * @param array $encryptionJwk the public key in JWK format
 	 * @param string $keyEncryptionAlg the algorithm to use for the key encryption
 	 * @param string $contentEncryptionAlg the algorithm to use for the content encryption
 	 * @return string
 	 */
 	public function createSerializedJweWithKey(
-		array $payloadArray, array $encryptionJwk,
+		string $payload, array $encryptionJwk,
 		string $keyEncryptionAlg = JwkService::PEM_ENC_KEY_ALGORITHM,
 		string $contentEncryptionAlg = self::CONTENT_ENCRYPTION_ALGORITHM,
 	): string {
@@ -66,11 +66,8 @@ public function createSerializedJweWithKey(
 		// Our key.
 		$jwk = new JWK($encryptionJwk);
 
-		// The payload we want to encrypt. It MUST be a string.
-		$payload = json_encode($payloadArray);
-
 		$jwe = $jweBuilder
-			->create()              // We want to create a new JWE
+			->create()            // We want to create a new JWE
 			->withPayload($payload) // We set the payload
 			->withSharedProtectedHeader([
 				// Key Encryption Algorithm
@@ -80,12 +77,14 @@ public function createSerializedJweWithKey(
 				// 'enc' => 'A256CBC-HS512',
 				'enc' => $contentEncryptionAlg,
 				//'zip' => 'DEF'            // Not recommended.
+				'cty' => 'JWT',
 			])
 			->addRecipient($jwk)    // We add a recipient (a shared key or public key).
 			->build();
 
-		$serializer = new CompactSerializer(); // The serializer
-		return $serializer->serialize($jwe, 0); // We serialize the recipient at index 0 (we only have one recipient).
+		$serializer = new CompactSerializer();
+		// We serialize the recipient at index 0 (we only have one recipient).
+		return $serializer->serialize($jwe, 0);
 	}
 
 	/**
@@ -171,13 +170,13 @@ public function decryptSerializedJwe(string $serializedJwe): string {
 		return $this->decryptSerializedJweWithKey($serializedJwe, $encPrivJwk);
 	}
 
-	public function createSerializedJwe(array $payloadArray): string {
+	public function createSerializedJwe(string $payload): string {
 		$myPemEncryptionKey = $this->jwkService->getMyEncryptionKey(true);
 		$sslEncryptionKey = openssl_pkey_get_private($myPemEncryptionKey);
 		$sslEncryptionKeyDetails = openssl_pkey_get_details($sslEncryptionKey);
 		$encPublicJwk = $this->jwkService->getJwkFromSslKey($sslEncryptionKeyDetails, isEncryptionKey: true);
 
-		return $this->createSerializedJweWithKey($payloadArray, $encPublicJwk);
+		return $this->createSerializedJweWithKey($payload, $encPublicJwk);
 	}
 
 	public function debug(): array {
@@ -203,7 +202,7 @@ public function debug(): array {
 		$serializedJweToken = $this->createSerializedJwe($payloadArray, $exampleJwkArray);
 		$decryptedJweString = $this->decryptSerializedJwe($serializedJweToken, $exampleJwkArray);
 		*/
-		$serializedJweToken = $this->createSerializedJweWithKey($payloadArray, $encPublicJwk);
+		$serializedJweToken = $this->createSerializedJweWithKey(json_encode($payloadArray), $encPublicJwk);
 		$jwtParts = explode('.', $serializedJweToken, 3);
 		$jwtHeader = json_decode(base64_decode($jwtParts[0]), true);
 		$decryptedJweString = $this->decryptSerializedJweWithKey($serializedJweToken, $encPrivJwk);
diff --git a/tests/unit/Service/JweServiceTest.php b/tests/unit/Service/JweServiceTest.php
index 20473872..8efc3c41 100644
--- a/tests/unit/Service/JweServiceTest.php
+++ b/tests/unit/Service/JweServiceTest.php
@@ -44,8 +44,9 @@ public function testJweEncryptionDecryption() {
 			'iss' => 'My service',
 			'aud' => 'Your application',
 		];
+		$inputPayload = json_encode($inputPayloadArray);
 
-		$serializedJweToken = $this->jweService->createSerializedJweWithKey($inputPayloadArray, $encPublicJwk);
+		$serializedJweToken = $this->jweService->createSerializedJweWithKey($inputPayload, $encPublicJwk);
 		$decryptedJweString = $this->jweService->decryptSerializedJweWithKey($serializedJweToken, $encPrivJwk);
 
 		$outputPayloadArray = json_decode($decryptedJweString, true);

From a0348aae18499b68754d9d94ef89d6ad496d0414 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Wed, 26 Nov 2025 10:30:51 +0100
Subject: [PATCH 17/25] make it possible to force-enable PKCE

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 README.md                          | 9 +++++++++
 lib/Controller/LoginController.php | 9 ++++++---
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 6590cc04..dddcc201 100644
--- a/README.md
+++ b/README.md
@@ -247,6 +247,15 @@ You can also manually disable it in `config.php`:
 ],
 ```
 
+You can also force the use of PKCE with:
+``` php
+'user_oidc' => [
+    'use_pkce' => 'force',
+],
+```
+This will make user_oidc use PKCE even if the `code_challenge_methods_supported` value of the provider's discovery endpoint
+is not defined or does not contain `S256`.
+
 ### Single logout
 
 Single logout is enabled by default. When logging out of Nextcloud,
diff --git a/lib/Controller/LoginController.php b/lib/Controller/LoginController.php
index db5affe9..4cb68b01 100644
--- a/lib/Controller/LoginController.php
+++ b/lib/Controller/LoginController.php
@@ -202,10 +202,11 @@ public function login(int $providerId, ?string $redirectUrl = null) {
 		$this->session->set(self::NONCE, $nonce);
 
 		$oidcSystemConfig = $this->config->getSystemValue('user_oidc', []);
-		// TODO add config param to force PKCE even if not supported in discovery
 		// condition becomes: ($isPkceSupported || $force) && ($oidcSystemConfig['use_pkce'] ?? true)
 		$isPkceSupported = in_array('S256', $discovery['code_challenge_methods_supported'] ?? [], true);
-		$isPkceEnabled = $isPkceSupported && ($oidcSystemConfig['use_pkce'] ?? true);
+		$usePkce = $oidcSystemConfig['use_pkce'] ?? true;
+		$forcePkce = $usePkce === 'force';
+		$isPkceEnabled = $forcePkce || ($isPkceSupported && $usePkce);
 
 		if ($isPkceEnabled) {
 			// PKCE code_challenge see https://datatracker.ietf.org/doc/html/rfc7636
@@ -407,7 +408,9 @@ public function code(string $state = '', string $code = '', string $scope = '',
 
 		$oidcSystemConfig = $this->config->getSystemValue('user_oidc', []);
 		$isPkceSupported = in_array('S256', $discovery['code_challenge_methods_supported'] ?? [], true);
-		$isPkceEnabled = $isPkceSupported && ($oidcSystemConfig['use_pkce'] ?? true);
+		$usePkce = $oidcSystemConfig['use_pkce'] ?? true;
+		$forcePkce = $usePkce === 'force';
+		$isPkceEnabled = $forcePkce || ($isPkceSupported && $usePkce);
 		$usePrivateKeyJwt = $this->providerService->getSetting($providerId, ProviderService::SETTING_USE_PRIVATE_KEY_JWT, '0') !== '0';
 
 		try {

From d3f9d9cb842c23e73d4dfd82ae109d8eb61d2852 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Wed, 26 Nov 2025 10:49:37 +0100
Subject: [PATCH 18/25] add error description in 403 template, use it in code
 controller method

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 lib/Controller/BaseOidcController.php | 9 ++++++++-
 lib/Controller/LoginController.php    | 2 +-
 templates/error.php                   | 6 ++++++
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/lib/Controller/BaseOidcController.php b/lib/Controller/BaseOidcController.php
index 34c7cf03..654bdbaa 100644
--- a/lib/Controller/BaseOidcController.php
+++ b/lib/Controller/BaseOidcController.php
@@ -55,13 +55,20 @@ protected function buildErrorTemplateResponse(string $message, int $statusCode,
 	 * @param int $statusCode
 	 * @param array $throttleMetadata
 	 * @param bool|null $throttle
+	 * @param string|null $errorDescription
 	 * @return TemplateResponse
 	 */
-	protected function build403TemplateResponse(string $message, int $statusCode, array $throttleMetadata = [], ?bool $throttle = null): TemplateResponse {
+	protected function build403TemplateResponse(
+		string $message, int $statusCode, array $throttleMetadata = [], ?bool $throttle = null,
+		?string $errorDescription = null,
+	): TemplateResponse {
 		$params = [
 			'message' => $message,
 			'title' => $this->l->t('Access forbidden'),
 		];
+		if ($errorDescription) {
+			$params['error_description'] = $errorDescription;
+		}
 		return $this->buildFailureTemplateResponse($params, $statusCode, $throttleMetadata, $throttle);
 	}
 
diff --git a/lib/Controller/LoginController.php b/lib/Controller/LoginController.php
index 4cb68b01..1403ecb0 100644
--- a/lib/Controller/LoginController.php
+++ b/lib/Controller/LoginController.php
@@ -365,7 +365,7 @@ public function code(string $state = '', string $code = '', string $scope = '',
 				], Http::STATUS_FORBIDDEN);
 			}
 			$message = $this->l10n->t('The identity provider failed to authenticate the user.');
-			return $this->build403TemplateResponse($message, Http::STATUS_BAD_REQUEST, [], false);
+			return $this->build403TemplateResponse($message, Http::STATUS_BAD_REQUEST, [], false, errorDescription: $error_description);
 		}
 
 		$storedState = $this->session->get(self::STATE);
diff --git a/templates/error.php b/templates/error.php
index 5d2ec473..5c4c6a92 100644
--- a/templates/error.php
+++ b/templates/error.php
@@ -10,6 +10,12 @@
         <li>
             <p><?php p($_['message']); ?></p>
         </li>
+        <?php
+		if (isset($_['error_description'])) {
+			echo '<li><p>';
+			p($_['error_description']);
+			echo '</p></li>';
+		} ?>
     </ul>
     <br>
     <p>

From 704ea0cf3a0f7a543bc5b2ae5951bb21cf4f5fce Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Thu, 27 Nov 2025 14:37:57 +0100
Subject: [PATCH 19/25] add regexp mechanism to parse user IDs from tokens

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 README.md                          | 22 ++++++++++++++++++++++
 lib/Controller/LoginController.php |  2 ++
 lib/Service/SettingsService.php    | 12 ++++++++++++
 lib/User/Backend.php               |  4 ++++
 4 files changed, 40 insertions(+)

diff --git a/README.md b/README.md
index dddcc201..51759b34 100644
--- a/README.md
+++ b/README.md
@@ -90,6 +90,28 @@ The OpenID Connect backend will ensure that user ids are unique even when multip
 id to ensure that a user cannot identify for the same Nextcloud account through different providers.
 Therefore, a hash of the provider id and the user id is used. This behaviour can be turned off in the provider options.
 
+### Parsing user IDs from claims
+
+If your ID tokens do not contain the user ID directly in an attribute/claim,
+you can configure user_oidc to apply a regular expression to extract the user ID from the claim.
+
+```php
+'user_oidc' => [
+  'user_id_regexp' => 'u=([^,]+)'
+]
+```
+
+This regular expression may or may not contain parenthesis. If it does, only the selected block will be extracted.
+Examples:
+
+* `'[a-zA-Z]+'`
+  * `'123-abc-123'` will give `'abc'`
+  * `'123-abc-345-def'` will give `'abc'`
+* `'u=([^,]+)'`
+  * `'u=123'` will give `'123'`
+  * `'anything,u=123,anything'` will give `'123'`
+  * `'anything,u=123,anything,u=345'` will give `'123'`
+
 ## Commandline settings
 The app could also be configured by commandline.
 
diff --git a/lib/Controller/LoginController.php b/lib/Controller/LoginController.php
index 1403ecb0..1066c773 100644
--- a/lib/Controller/LoginController.php
+++ b/lib/Controller/LoginController.php
@@ -608,6 +608,8 @@ public function code(string $state = '', string $code = '', string $scope = '',
 			return $this->build403TemplateResponse($message, Http::STATUS_BAD_REQUEST, ['reason' => 'failed to provision user']);
 		}
 
+		$userId = $this->settingsService->parseUserId($userId);
+
 		// prevent login of users that are not in a whitelisted group (if activated)
 		$restrictLoginToGroups = $this->providerService->getSetting($providerId, ProviderService::SETTING_RESTRICT_LOGIN_TO_GROUPS, '0');
 		if ($restrictLoginToGroups === '1') {
diff --git a/lib/Service/SettingsService.php b/lib/Service/SettingsService.php
index ffd75d34..177f7c96 100644
--- a/lib/Service/SettingsService.php
+++ b/lib/Service/SettingsService.php
@@ -13,12 +13,14 @@
 use OCA\UserOIDC\AppInfo\Application;
 use OCP\Exceptions\AppConfigTypeConflictException;
 use OCP\IAppConfig;
+use OCP\IConfig;
 use Psr\Log\LoggerInterface;
 
 class SettingsService {
 
 	public function __construct(
 		private IAppConfig $appConfig,
+		private IConfig $config,
 		private LoggerInterface $logger,
 	) {
 	}
@@ -41,4 +43,14 @@ public function setAllowMultipleUserBackEnds(bool $value): void {
 			$this->appConfig->setValueString(Application::APP_ID, 'allow_multiple_user_backends', $value ? '1' : '0', lazy: true);
 		}
 	}
+
+	public function parseUserId(string $userId): string {
+		$oidcSystemConfig = $this->config->getSystemValue('user_oidc', []);
+		if (isset($oidcSystemConfig['user_id_regexp']) && $oidcSystemConfig['user_id_regexp'] !== '') {
+			if (preg_match('/' . $oidcSystemConfig['user_id_regexp'] . '/', $userId, $matches) === 1) {
+				return $matches[1] ?? $matches[0];
+			}
+		}
+		return $userId;
+	}
 }
diff --git a/lib/User/Backend.php b/lib/User/Backend.php
index afd90e89..09ebc197 100644
--- a/lib/User/Backend.php
+++ b/lib/User/Backend.php
@@ -18,6 +18,7 @@
 use OCA\UserOIDC\Service\LdapService;
 use OCA\UserOIDC\Service\ProviderService;
 use OCA\UserOIDC\Service\ProvisioningService;
+use OCA\UserOIDC\Service\SettingsService;
 use OCA\UserOIDC\User\Validator\IBearerTokenValidator;
 use OCA\UserOIDC\User\Validator\SelfEncodedValidator;
 use OCA\UserOIDC\User\Validator\UserInfoValidator;
@@ -67,6 +68,7 @@ public function __construct(
 		private ProviderService $providerService,
 		private ProvisioningService $provisioningService,
 		private LdapService $ldapService,
+		private SettingsService $settingsService,
 		private IUserManager $userManager,
 		private ServerVersion $serverVersion,
 	) {
@@ -314,6 +316,8 @@ public function getCurrentUserId(): string {
 						$discovery = $this->discoveryService->obtainDiscovery($provider);
 						$this->eventDispatcher->dispatchTyped(new TokenValidatedEvent(['token' => $headerToken], $provider, $discovery));
 
+						$tokenUserId = $this->settingsService->parseUserId($tokenUserId);
+
 						if ($autoProvisionAllowed) {
 							// look for user in other backends
 							if (!$this->userManager->userExists($tokenUserId)) {

From 8123a16f806a5de1088445817ca49067e21131da Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Mon, 22 Dec 2025 15:49:52 +0100
Subject: [PATCH 20/25] make debug endpoints private

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 lib/Controller/ApiController.php | 2 --
 1 file changed, 2 deletions(-)

diff --git a/lib/Controller/ApiController.php b/lib/Controller/ApiController.php
index f51e653c..54a97d79 100644
--- a/lib/Controller/ApiController.php
+++ b/lib/Controller/ApiController.php
@@ -101,7 +101,6 @@ public function getJwks(): JSONResponse {
 	}
 
 	#[NoCSRFRequired]
-	#[PublicPage]
 	public function debugJwk(): JSONResponse {
 		try {
 			return new JSONResponse($this->jwkService->debug());
@@ -111,7 +110,6 @@ public function debugJwk(): JSONResponse {
 	}
 
 	#[NoCSRFRequired]
-	#[PublicPage]
 	public function debugJwe(): JSONResponse {
 		try {
 			return new JSONResponse($this->jweService->debug());

From f3f8c97681ac6daea0d4fc060756322a5c071e92 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Mon, 22 Dec 2025 15:58:57 +0100
Subject: [PATCH 21/25] handle errors when parsing JWT header at the end of the
 code flow

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 lib/Controller/LoginController.php | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/lib/Controller/LoginController.php b/lib/Controller/LoginController.php
index 1066c773..dc9cdcb3 100644
--- a/lib/Controller/LoginController.php
+++ b/lib/Controller/LoginController.php
@@ -505,15 +505,23 @@ public function code(string $state = '', string $code = '', string $scope = '',
 		$this->logger->debug('Received code response');
 		$this->eventDispatcher->dispatchTyped(new TokenObtainedEvent($data, $provider, $discovery));
 
-		// TODO: proper error handling
 		$idTokenRaw = $data['id_token'];
 		if ($usePrivateKeyJwt) {
-			// we could check the header there
 			// if kid is our private JWK, we have a JWE to decrypt
 			// if typ=JWT, we have a classic JWT to decode
 			$jwtParts = explode('.', $idTokenRaw, 3);
-			$jwtHeader = json_decode(JWT::urlsafeB64Decode($jwtParts[0]), true);
-			$this->logger->warning('JWT HEADER', ['jwt_header' => $jwtHeader]);
+			try {
+				$jwtHeader = json_decode(JWT::urlsafeB64Decode($jwtParts[0]), true, flags: JSON_THROW_ON_ERROR);
+			} catch (\JsonException $e) {
+				$this->logger->error('Malformed JWT id token header', ['exception' => $e]);
+				$message = $this->l10n->t('Failed to decode JWT id token header');
+				return $this->buildErrorTemplateResponse($message, Http::STATUS_BAD_REQUEST, throttle: false);
+			} catch (\Exception|\Throwable $e) {
+				$this->logger->error('Impossible to decode JWT id token header', ['exception' => $e]);
+				$message = $this->l10n->t('Failed to decode JWT id token header');
+				return $this->buildErrorTemplateResponse($message, Http::STATUS_BAD_REQUEST, throttle: false);
+			}
+			$this->logger->debug('JWT HEADER', ['jwt_header' => $jwtHeader]);
 			if (isset($jwtHeader['typ']) && $jwtHeader['typ'] === 'JWT') {
 				// we have a JWT, do nothing
 			} elseif (isset($jwtHeader['cty']) && $jwtHeader['cty'] === 'JWT') {

From 41be3fe6c210f59b1b0b4d806e7b7e89417dfdf1 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Mon, 22 Dec 2025 16:33:56 +0100
Subject: [PATCH 22/25] include leading and trailing / in the userId regexp

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 README.md                       |  6 +++---
 lib/Service/SettingsService.php | 11 +++++++++--
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 51759b34..5d6d6efa 100644
--- a/README.md
+++ b/README.md
@@ -97,17 +97,17 @@ you can configure user_oidc to apply a regular expression to extract the user ID
 
 ```php
 'user_oidc' => [
-  'user_id_regexp' => 'u=([^,]+)'
+  'user_id_regexp' => '/u=([^,]+)/'
 ]
 ```
 
 This regular expression may or may not contain parenthesis. If it does, only the selected block will be extracted.
 Examples:
 
-* `'[a-zA-Z]+'`
+* `'/[a-zA-Z]+/'`
   * `'123-abc-123'` will give `'abc'`
   * `'123-abc-345-def'` will give `'abc'`
-* `'u=([^,]+)'`
+* `'/u=([^,]+)/'`
   * `'u=123'` will give `'123'`
   * `'anything,u=123,anything'` will give `'123'`
   * `'anything,u=123,anything,u=345'` will give `'123'`
diff --git a/lib/Service/SettingsService.php b/lib/Service/SettingsService.php
index 177f7c96..a87628fd 100644
--- a/lib/Service/SettingsService.php
+++ b/lib/Service/SettingsService.php
@@ -46,8 +46,15 @@ public function setAllowMultipleUserBackEnds(bool $value): void {
 
 	public function parseUserId(string $userId): string {
 		$oidcSystemConfig = $this->config->getSystemValue('user_oidc', []);
-		if (isset($oidcSystemConfig['user_id_regexp']) && $oidcSystemConfig['user_id_regexp'] !== '') {
-			if (preg_match('/' . $oidcSystemConfig['user_id_regexp'] . '/', $userId, $matches) === 1) {
+		if (isset($oidcSystemConfig['user_id_regexp']) && is_string($oidcSystemConfig['user_id_regexp']) && $oidcSystemConfig['user_id_regexp'] !== '') {
+			// check that the regexp is valid
+			if (preg_match('/^\/.+\/[a-z]*$/', $oidcSystemConfig['user_id_regexp'], $matches) === 1) {
+				$this->logger->warning(
+					'Incorrect "user_id_regexp", it should start and end with a "/" and have optional trailing modifiers',
+					['regexp' => $oidcSystemConfig['user_id_regexp']],
+				);
+			}
+			if (preg_match($oidcSystemConfig['user_id_regexp'], $userId, $matches) === 1) {
 				return $matches[1] ?? $matches[0];
 			}
 		}

From 4fc9d406abd3ca98ab9892f7976c93be1d0f3a34 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Thu, 25 Dec 2025 13:14:48 +0100
Subject: [PATCH 23/25] implement encryption key rotation for JWE decryption

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 lib/Service/JweService.php            | 29 +++++++++++++--
 lib/Service/JwkService.php            | 53 ++++++++++++++++++---------
 tests/unit/Service/JweServiceTest.php |  7 +++-
 tests/unit/Service/JwkServiceTest.php |  8 ++--
 4 files changed, 72 insertions(+), 25 deletions(-)

diff --git a/lib/Service/JweService.php b/lib/Service/JweService.php
index 5aa2189f..4a2aac89 100644
--- a/lib/Service/JweService.php
+++ b/lib/Service/JweService.php
@@ -24,6 +24,8 @@
 use Jose\Component\Encryption\JWETokenSupport;
 use Jose\Component\Encryption\Serializer\CompactSerializer;
 use Jose\Component\Encryption\Serializer\JWESerializerManager;
+use OCP\AppFramework\Services\IAppConfig;
+use Psr\Log\LoggerInterface;
 
 class JweService {
 
@@ -31,6 +33,8 @@ class JweService {
 
 	public function __construct(
 		private JwkService $jwkService,
+		private IAppConfig $appConfig,
+		private LoggerInterface $logger,
 	) {
 	}
 
@@ -165,9 +169,28 @@ public function decryptSerializedJwe(string $serializedJwe): string {
 		$myPemEncryptionKey = $this->jwkService->getMyEncryptionKey(true);
 		$sslEncryptionKey = openssl_pkey_get_private($myPemEncryptionKey);
 		$sslEncryptionKeyDetails = openssl_pkey_get_details($sslEncryptionKey);
-		$encPrivJwk = $this->jwkService->getJwkFromSslKey($sslEncryptionKeyDetails, isEncryptionKey: true, includePrivateKey: true);
-
-		return $this->decryptSerializedJweWithKey($serializedJwe, $encPrivJwk);
+		$encryptionPrivateJwk = $this->jwkService->getJwkFromSslKey($sslEncryptionKeyDetails, isEncryptionKey: true, includePrivateKey: true);
+
+		try {
+			return $this->decryptSerializedJweWithKey($serializedJwe, $encryptionPrivateJwk);
+		} catch (\Exception $e) {
+			// try the old expired key
+			$oldPemEncryptionKey = $this->appConfig->getAppValueString(JwkService::PEM_EXPIRED_ENC_KEY_SETTINGS_KEY, lazy: true);
+			$oldPemEncryptionKeyCreatedAt = $this->appConfig->getAppValueInt(JwkService::PEM_EXPIRED_ENC_KEY_CREATED_AT_SETTINGS_KEY, lazy: true);
+			if ($oldPemEncryptionKey === '' || $oldPemEncryptionKeyCreatedAt === 0) {
+				$this->logger->debug('JWE decryption failed with a fresh key and there is no old key');
+				throw $e;
+			}
+			// the old encryption key is expired for more than an hour, we can't use it
+			if (time() > $oldPemEncryptionKeyCreatedAt + JwkService::PEM_ENC_KEY_EXPIRES_AFTER_SECONDS + (60 * 60)) {
+				$this->logger->debug('JWE decryption failed with a fresh key and the old key is expired for more than an hour');
+				throw $e;
+			}
+			$oldSslEncryptionKey = openssl_pkey_get_private($oldPemEncryptionKey);
+			$oldSslEncryptionKeyDetails = openssl_pkey_get_details($oldSslEncryptionKey);
+			$oldEncryptionPrivateJwk = $this->jwkService->getJwkFromSslKey($oldSslEncryptionKeyDetails, isEncryptionKey: true, includePrivateKey: true);
+			return $this->decryptSerializedJweWithKey($serializedJwe, $oldEncryptionPrivateJwk);
+		}
 	}
 
 	public function createSerializedJwe(string $payload): string {
diff --git a/lib/Service/JwkService.php b/lib/Service/JwkService.php
index 3ec3c199..7a7940e7 100644
--- a/lib/Service/JwkService.php
+++ b/lib/Service/JwkService.php
@@ -19,16 +19,19 @@
 class JwkService {
 
 	public const PEM_SIG_KEY_SETTINGS_KEY = 'pemSignatureKey';
-	public const PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY = 'pemSignatureKeyExpiresAt';
-	public const PEM_SIG_KEY_EXPIRES_IN_SECONDS = 60 * 60;
+	public const PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY = 'pemSignatureKeyCreatedAt';
+	public const PEM_SIG_KEY_EXPIRES_AFTER_SECONDS = 60 * 60;
 	public const PEM_SIG_KEY_ALGORITHM = 'ES384';
 	public const PEM_SIG_KEY_CURVE = 'P-384';
 
 	public const PEM_ENC_KEY_SETTINGS_KEY = 'pemEncryptionKey';
-	public const PEM_ENC_KEY_EXPIRES_AT_SETTINGS_KEY = 'pemEncryptionKeyExpiresAt';
-	public const PEM_ENC_KEY_EXPIRES_IN_SECONDS = 60 * 60;
+	public const PEM_ENC_KEY_CREATED_AT_SETTINGS_KEY = 'pemEncryptionKeyCreatedAt';
+	public const PEM_ENC_KEY_EXPIRES_AFTER_SECONDS = 60 * 60;
 	public const PEM_ENC_KEY_ALGORITHM = 'ECDH-ES+A192KW';
 	public const PEM_ENC_KEY_CURVE = 'P-384';
+	// we store the expired encryption key and can use it for one extra hour after a new one has been generated
+	public const PEM_EXPIRED_ENC_KEY_SETTINGS_KEY = 'pemExpiredEncryptionKey';
+	public const PEM_EXPIRED_ENC_KEY_CREATED_AT_SETTINGS_KEY = 'pemExpiredEncryptionKeyCreatedAt';
 
 	public function __construct(
 		private IAppConfig $appConfig,
@@ -44,13 +47,15 @@ public function __construct(
 	 */
 	public function getMyPemSignatureKey(bool $refresh = true): string {
 		$pemSignatureKey = $this->appConfig->getAppValueString(self::PEM_SIG_KEY_SETTINGS_KEY, lazy: true);
-		$pemSignatureKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
+		$pemSignatureKeyCreatedAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY, lazy: true);
 
-		if ($pemSignatureKey === '' || $pemSignatureKeyExpiresAt === 0 || ($refresh && time() > $pemSignatureKeyExpiresAt)) {
+		if ($pemSignatureKey === ''
+			|| $pemSignatureKeyCreatedAt === 0
+			|| ($refresh && (time() > $pemSignatureKeyCreatedAt + self::PEM_SIG_KEY_EXPIRES_AFTER_SECONDS))) {
 			$pemSignatureKey = $this->generatePemPrivateKey();
 			// store the key
 			$this->appConfig->setAppValueString(self::PEM_SIG_KEY_SETTINGS_KEY, $pemSignatureKey, lazy: true);
-			$this->appConfig->setAppValueInt(self::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, time() + self::PEM_SIG_KEY_EXPIRES_IN_SECONDS, lazy: true);
+			$this->appConfig->setAppValueInt(self::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY, time(), lazy: true);
 		}
 		return $pemSignatureKey;
 	}
@@ -64,13 +69,24 @@ public function getMyPemSignatureKey(bool $refresh = true): string {
 	 */
 	public function getMyEncryptionKey(bool $refresh = true): string {
 		$pemEncryptionKey = $this->appConfig->getAppValueString(self::PEM_ENC_KEY_SETTINGS_KEY, lazy: true);
-		$pemEncryptionKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_ENC_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
-
-		if ($pemEncryptionKey === '' || $pemEncryptionKeyExpiresAt === 0 || ($refresh && time() > $pemEncryptionKeyExpiresAt)) {
+		$pemEncryptionKeyCreatedAt = $this->appConfig->getAppValueInt(self::PEM_ENC_KEY_CREATED_AT_SETTINGS_KEY, lazy: true);
+
+		if ($pemEncryptionKey === ''
+			|| $pemEncryptionKeyCreatedAt === 0
+			|| ($refresh && (time() > $pemEncryptionKeyCreatedAt + self::PEM_ENC_KEY_EXPIRES_AFTER_SECONDS))
+		) {
+			// if we have an old expired key, keep it for one hour
+			if ($pemEncryptionKey !== ''
+				&& $pemEncryptionKeyCreatedAt !== 0
+				&& (time() > $pemEncryptionKeyCreatedAt + self::PEM_ENC_KEY_EXPIRES_AFTER_SECONDS)) {
+				$this->appConfig->setAppValueString(self::PEM_EXPIRED_ENC_KEY_SETTINGS_KEY, $pemEncryptionKey, lazy: true);
+				$this->appConfig->setAppValueInt(self::PEM_EXPIRED_ENC_KEY_CREATED_AT_SETTINGS_KEY, $pemEncryptionKeyCreatedAt, lazy: true);
+			}
+			// generate a new key
 			$pemEncryptionKey = $this->generatePemPrivateKey();
 			// store the key
 			$this->appConfig->setAppValueString(self::PEM_ENC_KEY_SETTINGS_KEY, $pemEncryptionKey, lazy: true);
-			$this->appConfig->setAppValueInt(self::PEM_ENC_KEY_EXPIRES_AT_SETTINGS_KEY, time() + self::PEM_ENC_KEY_EXPIRES_IN_SECONDS, lazy: true);
+			$this->appConfig->setAppValueInt(self::PEM_ENC_KEY_CREATED_AT_SETTINGS_KEY, time(), lazy: true);
 		}
 		return $pemEncryptionKey;
 	}
@@ -122,11 +138,14 @@ public function getJwks(): array {
 	}
 
 	public function getJwkFromSslKey(array $sslKeyDetails, bool $isEncryptionKey = false, bool $includePrivateKey = false): array {
-		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
+		$pemPrivateKeyCreatedAt = $this->appConfig->getAppValueInt(
+			$isEncryptionKey ? self::PEM_ENC_KEY_CREATED_AT_SETTINGS_KEY : self::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY,
+			lazy: true,
+		);
 		$jwk = [
 			'kty' => 'EC',
 			'use' => $isEncryptionKey ? 'enc' : 'sig',
-			'kid' => ($isEncryptionKey ? 'enc' : 'sig') . '_key_' . $pemPrivateKeyExpiresAt,
+			'kid' => ($isEncryptionKey ? 'enc' : 'sig') . '_key_' . $pemPrivateKeyCreatedAt,
 			'crv' => $isEncryptionKey ? self::PEM_ENC_KEY_CURVE : self::PEM_SIG_KEY_CURVE,
 			'x' => \rtrim(\strtr(\base64_encode($sslKeyDetails['ec']['x']), '+/', '-_'), '='),
 			'y' => \rtrim(\strtr(\base64_encode($sslKeyDetails['ec']['y']), '+/', '-_'), '='),
@@ -155,7 +174,7 @@ public function generateClientAssertion(Provider $provider, string $discoveryIss
 		// we refresh (if needed) here to make sure we use a key that will be served to the IdP in a few seconds
 		$myPemPrivateKey = $this->getMyPemSignatureKey();
 		$sslPrivateKey = openssl_pkey_get_private($myPemPrivateKey);
-		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
+		$pemSignatureKeyCreatedAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY, lazy: true);
 
 		$payload = [
 			'sub' => $provider->getClientId(),
@@ -170,7 +189,7 @@ public function generateClientAssertion(Provider $provider, string $discoveryIss
 			$payload['code'] = $code;
 		}
 
-		return $this->createJwt($payload, $sslPrivateKey, 'sig_key_' . $pemPrivateKeyExpiresAt, self::PEM_SIG_KEY_ALGORITHM);
+		return $this->createJwt($payload, $sslPrivateKey, 'sig_key_' . $pemSignatureKeyCreatedAt, self::PEM_SIG_KEY_ALGORITHM);
 	}
 
 	public function debug(): array {
@@ -180,8 +199,8 @@ public function debug(): array {
 		$pubKeyPem = $pubKey['key'];
 
 		$payload = ['lll' => 'aaa'];
-		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
-		$signedJwtToken = $this->createJwt($payload, $sslPrivateKey, 'sig_key_' . $pemPrivateKeyExpiresAt, self::PEM_SIG_KEY_ALGORITHM);
+		$pemSignatureKeyCreatedAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY, lazy: true);
+		$signedJwtToken = $this->createJwt($payload, $sslPrivateKey, 'sig_key_' . $pemSignatureKeyCreatedAt, self::PEM_SIG_KEY_ALGORITHM);
 
 		// check content of JWT
 		$rawJwks = ['keys' => [$this->getJwkFromSslKey($pubKey)]];
diff --git a/tests/unit/Service/JweServiceTest.php b/tests/unit/Service/JweServiceTest.php
index 8efc3c41..4e91cbb1 100644
--- a/tests/unit/Service/JweServiceTest.php
+++ b/tests/unit/Service/JweServiceTest.php
@@ -13,6 +13,7 @@
 use OCP\AppFramework\Services\IAppConfig;
 use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
+use Psr\Log\LoggerInterface;
 
 class JweServiceTest extends TestCase {
 
@@ -27,7 +28,11 @@ public function setUp(): void {
 		parent::setUp();
 		$this->appConfig = $this->createMock(IAppConfig::class);
 		$this->jwkService = new JwkService($this->appConfig);
-		$this->jweService = new JweService($this->jwkService);
+		$this->jweService = new JweService(
+			$this->jwkService,
+			$this->appConfig,
+			$this->createMock(LoggerInterface::class),
+		);
 	}
 
 	public function testJweEncryptionDecryption() {
diff --git a/tests/unit/Service/JwkServiceTest.php b/tests/unit/Service/JwkServiceTest.php
index 98b7350f..d97d6742 100644
--- a/tests/unit/Service/JwkServiceTest.php
+++ b/tests/unit/Service/JwkServiceTest.php
@@ -39,8 +39,8 @@ public function testSignatureKeyAndJwt() {
 		$this->assertStringContainsString('-----END PRIVATE KEY-----', $myPemPrivateKey);
 
 		$initialPayload = ['nice' => 'example'];
-		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(JwkService::PEM_SIG_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
-		$jwkId = 'sig_key_' . $pemPrivateKeyExpiresAt;
+		$pemSignatureKeyCreatedAt = $this->appConfig->getAppValueInt(JwkService::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY, lazy: true);
+		$jwkId = 'sig_key_' . $pemSignatureKeyCreatedAt;
 		$signedJwtToken = $this->jwkService->createJwt($initialPayload, $sslPrivateKey, $jwkId, JwkService::PEM_SIG_KEY_ALGORITHM);
 
 		// check JWK
@@ -72,8 +72,8 @@ public function testEncryptionKey() {
 		$sslEncryptionKeyDetails = openssl_pkey_get_details($sslEncryptionKey);
 		$encJwk = $this->jwkService->getJwkFromSslKey($sslEncryptionKeyDetails, isEncryptionKey: true);
 
-		$pemPrivateKeyExpiresAt = $this->appConfig->getAppValueInt(JwkService::PEM_ENC_KEY_EXPIRES_AT_SETTINGS_KEY, lazy: true);
-		$encJwkId = 'enc_key_' . $pemPrivateKeyExpiresAt;
+		$pemEncryptionKeyCreatedAt = $this->appConfig->getAppValueInt(JwkService::PEM_ENC_KEY_CREATED_AT_SETTINGS_KEY, lazy: true);
+		$encJwkId = 'enc_key_' . $pemEncryptionKeyCreatedAt;
 
 		$this->assertEquals('EC', $encJwk['kty']);
 		$this->assertEquals('enc', $encJwk['use']);

From 12950b514836a90242a4b5fb2b00f06aa9cb066e Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Thu, 26 Mar 2026 14:12:10 +0100
Subject: [PATCH 24/25] do not log sensitive data, fix user_id regexp logic,
 only decrypt client secret if needed

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 lib/Controller/LoginController.php | 26 +++++++++++++++-----------
 lib/Service/SettingsService.php    |  4 +++-
 2 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/lib/Controller/LoginController.php b/lib/Controller/LoginController.php
index dc9cdcb3..d16bc169 100644
--- a/lib/Controller/LoginController.php
+++ b/lib/Controller/LoginController.php
@@ -394,14 +394,6 @@ public function code(string $state = '', string $code = '', string $scope = '',
 
 		$providerId = (int)$this->session->get(self::PROVIDERID);
 		$provider = $this->providerMapper->getProvider($providerId);
-		try {
-			$providerClientSecret = $this->crypto->decrypt($provider->getClientSecret());
-		} catch (\Exception $e) {
-			$this->logger->error('Failed to decrypt the client secret', ['exception' => $e]);
-			$message = $this->l10n->t('Failed to decrypt the OIDC provider client secret');
-			return $this->buildErrorTemplateResponse($message, Http::STATUS_BAD_REQUEST, [], false);
-		}
-
 		$discovery = $this->discoveryService->obtainDiscovery($provider);
 
 		$this->logger->debug('Obtainting data from: ' . $discovery['token_endpoint']);
@@ -443,6 +435,13 @@ public function code(string $state = '', string $code = '', string $scope = '',
 
 			// private key JWT auth does not work with client_secret_basic, we don't wanna pass the client secret
 			if ($tokenEndpointAuthMethod === 'client_secret_basic' && !$usePrivateKeyJwt) {
+				try {
+					$providerClientSecret = $this->crypto->decrypt($provider->getClientSecret());
+				} catch (\Exception $e) {
+					$this->logger->error('Failed to decrypt the client secret', ['exception' => $e]);
+					$message = $this->l10n->t('Failed to decrypt the OIDC provider client secret');
+					return $this->buildErrorTemplateResponse($message, Http::STATUS_BAD_REQUEST, [], false);
+				}
 				$headers = [
 					'Authorization' => 'Basic ' . base64_encode($provider->getClientId() . ':' . $providerClientSecret),
 					'Content-Type' => 'application/x-www-form-urlencoded',
@@ -454,6 +453,13 @@ public function code(string $state = '', string $code = '', string $scope = '',
 					$requestBody['client_assertion_type'] = 'urn:ietf:params:oauth:client-assertion-type:jwt-bearer';
 					$requestBody['client_assertion'] = $this->jwkService->generateClientAssertion($provider, $discovery['issuer'], $code);
 				} else {
+					try {
+						$providerClientSecret = $this->crypto->decrypt($provider->getClientSecret());
+					} catch (\Exception $e) {
+						$this->logger->error('Failed to decrypt the client secret', ['exception' => $e]);
+						$message = $this->l10n->t('Failed to decrypt the OIDC provider client secret');
+						return $this->buildErrorTemplateResponse($message, Http::STATUS_BAD_REQUEST, [], false);
+					}
 					$requestBody['client_secret'] = $providerClientSecret;
 				}
 			}
@@ -527,10 +533,8 @@ public function code(string $state = '', string $code = '', string $scope = '',
 			} elseif (isset($jwtHeader['cty']) && $jwtHeader['cty'] === 'JWT') {
 				// we have a JWE that contains the JWT string (the ID token)
 				$idTokenRaw = $this->jweService->decryptSerializedJwe($idTokenRaw);
-				$this->logger->warning('raw decrypted JWE', ['decrypted_jwe' => $idTokenRaw]);
-				$this->logger->warning('decrypted+decoded JWE', ['decrypted_jwe' => json_decode($idTokenRaw, true)]);
 			} else {
-				$this->logger->warning('Unsupported id_token when using "private key JWT"', ['id_token' => $idTokenRaw]);
+				$this->logger->warning('Unsupported id_token when using "private key JWT"');
 			}
 		}
 		$jwks = $this->discoveryService->obtainJWK($provider, $idTokenRaw);
diff --git a/lib/Service/SettingsService.php b/lib/Service/SettingsService.php
index a87628fd..d09198bb 100644
--- a/lib/Service/SettingsService.php
+++ b/lib/Service/SettingsService.php
@@ -48,12 +48,14 @@ public function parseUserId(string $userId): string {
 		$oidcSystemConfig = $this->config->getSystemValue('user_oidc', []);
 		if (isset($oidcSystemConfig['user_id_regexp']) && is_string($oidcSystemConfig['user_id_regexp']) && $oidcSystemConfig['user_id_regexp'] !== '') {
 			// check that the regexp is valid
-			if (preg_match('/^\/.+\/[a-z]*$/', $oidcSystemConfig['user_id_regexp'], $matches) === 1) {
+			if (preg_match('/^\/.+\/[a-z]*$/', $oidcSystemConfig['user_id_regexp']) !== 1) {
 				$this->logger->warning(
 					'Incorrect "user_id_regexp", it should start and end with a "/" and have optional trailing modifiers',
 					['regexp' => $oidcSystemConfig['user_id_regexp']],
 				);
+				return $userId;
 			}
+			// return the potential bracket block, fallback to the entire match
 			if (preg_match($oidcSystemConfig['user_id_regexp'], $userId, $matches) === 1) {
 				return $matches[1] ?? $matches[0];
 			}

From 1e57757504ac0fce3654201295e7a86a2e7860c5 Mon Sep 17 00:00:00 2001
From: Julien Veyssier <julien-nc@posteo.net>
Date: Thu, 26 Mar 2026 14:56:14 +0100
Subject: [PATCH 25/25] [WARNING] needs logic check: improve signature key
 rotation

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>
---
 lib/Service/JwkService.php            | 116 +++++++++++++++++++++-----
 tests/unit/Service/JwkServiceTest.php |  57 +++++++++++++
 2 files changed, 151 insertions(+), 22 deletions(-)

diff --git a/lib/Service/JwkService.php b/lib/Service/JwkService.php
index 7a7940e7..8517d35d 100644
--- a/lib/Service/JwkService.php
+++ b/lib/Service/JwkService.php
@@ -20,6 +20,8 @@ class JwkService {
 
 	public const PEM_SIG_KEY_SETTINGS_KEY = 'pemSignatureKey';
 	public const PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY = 'pemSignatureKeyCreatedAt';
+	public const PEM_NEXT_SIG_KEY_SETTINGS_KEY = 'pemNextSignatureKey';
+	public const PEM_NEXT_SIG_KEY_CREATED_AT_SETTINGS_KEY = 'pemNextSignatureKeyCreatedAt';
 	public const PEM_SIG_KEY_EXPIRES_AFTER_SECONDS = 60 * 60;
 	public const PEM_SIG_KEY_ALGORITHM = 'ES384';
 	public const PEM_SIG_KEY_CURVE = 'P-384';
@@ -39,25 +41,16 @@ public function __construct(
 	}
 
 	/**
-	 * Get our stored signature PEM key (or regenerate it if it's expired)
+	 * Get our current signature PEM key after applying rotation if needed.
 	 *
-	 * @param bool $refresh
 	 * @return string
 	 * @throws AppConfigTypeConflictException
 	 */
-	public function getMyPemSignatureKey(bool $refresh = true): string {
-		$pemSignatureKey = $this->appConfig->getAppValueString(self::PEM_SIG_KEY_SETTINGS_KEY, lazy: true);
-		$pemSignatureKeyCreatedAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY, lazy: true);
+	public function getMyPemSignatureKey(): string {
+		$this->ensureSignatureKeysInitialized();
+		$this->rotateSignatureKeysIfNeeded();
 
-		if ($pemSignatureKey === ''
-			|| $pemSignatureKeyCreatedAt === 0
-			|| ($refresh && (time() > $pemSignatureKeyCreatedAt + self::PEM_SIG_KEY_EXPIRES_AFTER_SECONDS))) {
-			$pemSignatureKey = $this->generatePemPrivateKey();
-			// store the key
-			$this->appConfig->setAppValueString(self::PEM_SIG_KEY_SETTINGS_KEY, $pemSignatureKey, lazy: true);
-			$this->appConfig->setAppValueInt(self::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY, time(), lazy: true);
-		}
-		return $pemSignatureKey;
+		return $this->appConfig->getAppValueString(self::PEM_SIG_KEY_SETTINGS_KEY, lazy: true);
 	}
 
 	/**
@@ -123,22 +116,34 @@ public function generatePemPrivateKey(): string {
 	 * @throws AppConfigTypeConflictException
 	 */
 	public function getJwks(): array {
-		// we don't refresh here to make sure the IdP will get the key that was used to sign the client assertion
-		$myPemSignatureKey = $this->getMyPemSignatureKey(false);
+		$myPemSignatureKey = $this->getMyPemSignatureKey();
+		$pemSignatureKeyCreatedAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY, lazy: true);
 		$sslSignatureKey = openssl_pkey_get_private($myPemSignatureKey);
 		$sslSignatureKeyDetails = openssl_pkey_get_details($sslSignatureKey);
 
+		$myNextPemSignatureKey = $this->appConfig->getAppValueString(self::PEM_NEXT_SIG_KEY_SETTINGS_KEY, lazy: true);
+		$nextPemSignatureKeyCreatedAt = $this->appConfig->getAppValueInt(self::PEM_NEXT_SIG_KEY_CREATED_AT_SETTINGS_KEY, lazy: true);
+		$sslNextSignatureKey = openssl_pkey_get_private($myNextPemSignatureKey);
+		$sslNextSignatureKeyDetails = openssl_pkey_get_details($sslNextSignatureKey);
+
 		$myPemEncryptionKey = $this->getMyEncryptionKey(true);
+		$pemEncryptionKeyCreatedAt = $this->appConfig->getAppValueInt(self::PEM_ENC_KEY_CREATED_AT_SETTINGS_KEY, lazy: true);
 		$sslEncryptionKey = openssl_pkey_get_private($myPemEncryptionKey);
 		$sslEncryptionKeyDetails = openssl_pkey_get_details($sslEncryptionKey);
 		return [
-			$this->getJwkFromSslKey($sslSignatureKeyDetails),
-			$this->getJwkFromSslKey($sslEncryptionKeyDetails, isEncryptionKey: true),
+			$this->getJwkFromSslKey($sslSignatureKeyDetails, keyCreatedAt: $pemSignatureKeyCreatedAt),
+			$this->getJwkFromSslKey($sslNextSignatureKeyDetails, keyCreatedAt: $nextPemSignatureKeyCreatedAt),
+			$this->getJwkFromSslKey($sslEncryptionKeyDetails, isEncryptionKey: true, keyCreatedAt: $pemEncryptionKeyCreatedAt),
 		];
 	}
 
-	public function getJwkFromSslKey(array $sslKeyDetails, bool $isEncryptionKey = false, bool $includePrivateKey = false): array {
-		$pemPrivateKeyCreatedAt = $this->appConfig->getAppValueInt(
+	public function getJwkFromSslKey(
+		array $sslKeyDetails,
+		bool $isEncryptionKey = false,
+		bool $includePrivateKey = false,
+		?int $keyCreatedAt = null,
+	): array {
+		$pemPrivateKeyCreatedAt = $keyCreatedAt ?? $this->appConfig->getAppValueInt(
 			$isEncryptionKey ? self::PEM_ENC_KEY_CREATED_AT_SETTINGS_KEY : self::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY,
 			lazy: true,
 		);
@@ -171,7 +176,7 @@ public function createJwt(array $payload, \OpenSSLAsymmetricKey $key, string $ke
 	}
 
 	public function generateClientAssertion(Provider $provider, string $discoveryIssuer, ?string $code = null): string {
-		// we refresh (if needed) here to make sure we use a key that will be served to the IdP in a few seconds
+		// make sure we sign with the currently active key, while the next one is already pre-published
 		$myPemPrivateKey = $this->getMyPemSignatureKey();
 		$sslPrivateKey = openssl_pkey_get_private($myPemPrivateKey);
 		$pemSignatureKeyCreatedAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY, lazy: true);
@@ -213,7 +218,7 @@ public function debug(): array {
 		$jwtHeader = json_decode(JWT::urlsafeB64Decode($jwtParts[0]), true);
 
 		return [
-			'public_jwk' => $this->getJwkFromSslKey($pubKey),
+			'public_jwk' => $this->getJwkFromSslKey($pubKey, keyCreatedAt: $pemSignatureKeyCreatedAt),
 			'public_pem' => $pubKeyPem,
 			'private_pem' => $myPemPrivateKey,
 			'initial_payload' => $payload,
@@ -223,4 +228,71 @@ public function debug(): array {
 			'arrays_are_equal' => $payload === $jwtPayloadArray,
 		];
 	}
+
+	private function ensureSignatureKeysInitialized(): void {
+		$currentPem = $this->appConfig->getAppValueString(self::PEM_SIG_KEY_SETTINGS_KEY, lazy: true);
+		$currentCreatedAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY, lazy: true);
+		$nextPem = $this->appConfig->getAppValueString(self::PEM_NEXT_SIG_KEY_SETTINGS_KEY, lazy: true);
+		$nextCreatedAt = $this->appConfig->getAppValueInt(self::PEM_NEXT_SIG_KEY_CREATED_AT_SETTINGS_KEY, lazy: true);
+
+		if ($currentPem === '' || $currentCreatedAt === 0) {
+			if ($nextPem !== '' && $nextCreatedAt !== 0) {
+				$this->storeSignatureKey(self::PEM_SIG_KEY_SETTINGS_KEY, self::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY, $nextPem, $nextCreatedAt);
+				$currentPem = $nextPem;
+				$currentCreatedAt = $nextCreatedAt;
+				$nextPem = '';
+				$nextCreatedAt = 0;
+			} else {
+				$currentCreatedAt = $this->getFreshKeyCreatedAt();
+				$currentPem = $this->generatePemPrivateKey();
+				$this->storeSignatureKey(self::PEM_SIG_KEY_SETTINGS_KEY, self::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY, $currentPem, $currentCreatedAt);
+			}
+		}
+
+		if ($nextPem === '' || $nextCreatedAt === 0) {
+			$nextCreatedAt = $this->getFreshKeyCreatedAt($currentCreatedAt);
+			$nextPem = $this->generatePemPrivateKey();
+			$this->storeSignatureKey(self::PEM_NEXT_SIG_KEY_SETTINGS_KEY, self::PEM_NEXT_SIG_KEY_CREATED_AT_SETTINGS_KEY, $nextPem, $nextCreatedAt);
+		}
+	}
+
+	private function rotateSignatureKeysIfNeeded(): void {
+		$currentCreatedAt = $this->appConfig->getAppValueInt(self::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY, lazy: true);
+		$nextPem = $this->appConfig->getAppValueString(self::PEM_NEXT_SIG_KEY_SETTINGS_KEY, lazy: true);
+		$nextCreatedAt = $this->appConfig->getAppValueInt(self::PEM_NEXT_SIG_KEY_CREATED_AT_SETTINGS_KEY, lazy: true);
+
+		if (!$this->shouldRotateSignatureKeys($currentCreatedAt, $nextCreatedAt) || $nextPem === '') {
+			return;
+		}
+
+		$this->storeSignatureKey(self::PEM_SIG_KEY_SETTINGS_KEY, self::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY, $nextPem, $nextCreatedAt);
+
+		$freshNextCreatedAt = $this->getFreshKeyCreatedAt($nextCreatedAt);
+		$this->storeSignatureKey(
+			self::PEM_NEXT_SIG_KEY_SETTINGS_KEY,
+			self::PEM_NEXT_SIG_KEY_CREATED_AT_SETTINGS_KEY,
+			$this->generatePemPrivateKey(),
+			$freshNextCreatedAt,
+		);
+	}
+
+	private function shouldRotateSignatureKeys(int $currentCreatedAt, int $nextCreatedAt): bool {
+		if ($currentCreatedAt === 0 || $nextCreatedAt === 0) {
+			return false;
+		}
+
+		$now = time();
+		return $now > $currentCreatedAt + self::PEM_SIG_KEY_EXPIRES_AFTER_SECONDS
+			&& $now > $nextCreatedAt + self::PEM_SIG_KEY_EXPIRES_AFTER_SECONDS;
+	}
+
+	private function getFreshKeyCreatedAt(int ...$existingCreatedAt): int {
+		$latestExistingCreatedAt = $existingCreatedAt === [] ? 0 : max($existingCreatedAt);
+		return max(time(), $latestExistingCreatedAt + 1);
+	}
+
+	private function storeSignatureKey(string $keySetting, string $createdAtSetting, string $pemKey, int $createdAt): void {
+		$this->appConfig->setAppValueString($keySetting, $pemKey, lazy: true);
+		$this->appConfig->setAppValueInt($createdAtSetting, $createdAt, lazy: true);
+	}
 }
diff --git a/tests/unit/Service/JwkServiceTest.php b/tests/unit/Service/JwkServiceTest.php
index d97d6742..cdce9474 100644
--- a/tests/unit/Service/JwkServiceTest.php
+++ b/tests/unit/Service/JwkServiceTest.php
@@ -8,6 +8,7 @@
 declare(strict_types=1);
 
 
+use OCA\UserOIDC\Db\Provider;
 use OCA\UserOIDC\Service\JwkService;
 use OCA\UserOIDC\Vendor\Firebase\JWT\JWK;
 use OCA\UserOIDC\Vendor\Firebase\JWT\JWT;
@@ -21,10 +22,30 @@ class JwkServiceTest extends TestCase {
 	private $appConfig;
 	/** @var JwkService|MockObject */
 	private $jwkService;
+	private array $appConfigStrings = [];
+	private array $appConfigInts = [];
 
 	public function setUp(): void {
 		parent::setUp();
 		$this->appConfig = $this->createMock(IAppConfig::class);
+		$this->appConfig->method('getAppValueString')
+			->willReturnCallback(function (string $key, ?string $default = null, bool $lazy = false) {
+				return $this->appConfigStrings[$key] ?? ($default ?? '');
+			});
+		$this->appConfig->method('getAppValueInt')
+			->willReturnCallback(function (string $key, ?int $default = null, bool $lazy = false) {
+				return $this->appConfigInts[$key] ?? ($default ?? 0);
+			});
+		$this->appConfig->method('setAppValueString')
+			->willReturnCallback(function (string $key, string $value, bool $lazy = false) {
+				$this->appConfigStrings[$key] = $value;
+				return true;
+			});
+		$this->appConfig->method('setAppValueInt')
+			->willReturnCallback(function (string $key, int $value, bool $lazy = false) {
+				$this->appConfigInts[$key] = $value;
+				return true;
+			});
 		$this->jwkService = new JwkService($this->appConfig);
 	}
 
@@ -81,4 +102,40 @@ public function testEncryptionKey() {
 		$this->assertEquals(JwkService::PEM_ENC_KEY_CURVE, $encJwk['crv']);
 		$this->assertEquals(JwkService::PEM_ENC_KEY_ALGORITHM, $encJwk['alg']);
 	}
+
+	public function testJwksContainsCurrentAndNextSignatureKeys(): void {
+		$jwks = $this->jwkService->getJwks();
+
+		$this->assertCount(3, $jwks);
+		$this->assertSame('sig', $jwks[0]['use']);
+		$this->assertSame('sig', $jwks[1]['use']);
+		$this->assertSame('enc', $jwks[2]['use']);
+		$this->assertNotSame($jwks[0]['kid'], $jwks[1]['kid']);
+	}
+
+	public function testExpiredCurrentSignatureKeyPromotesPrepublishedNextKey(): void {
+		$oldCurrentKey = $this->jwkService->generatePemPrivateKey();
+		$oldNextKey = $this->jwkService->generatePemPrivateKey();
+		$oldCurrentCreatedAt = time() - JwkService::PEM_SIG_KEY_EXPIRES_AFTER_SECONDS - 20;
+		$oldNextCreatedAt = time() - JwkService::PEM_SIG_KEY_EXPIRES_AFTER_SECONDS - 10;
+
+		$this->appConfigStrings[JwkService::PEM_SIG_KEY_SETTINGS_KEY] = $oldCurrentKey;
+		$this->appConfigInts[JwkService::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY] = $oldCurrentCreatedAt;
+		$this->appConfigStrings[JwkService::PEM_NEXT_SIG_KEY_SETTINGS_KEY] = $oldNextKey;
+		$this->appConfigInts[JwkService::PEM_NEXT_SIG_KEY_CREATED_AT_SETTINGS_KEY] = $oldNextCreatedAt;
+
+		$provider = new Provider();
+		$provider->setClientId('client-id');
+
+		$this->jwkService->generateClientAssertion($provider, 'https://issuer.example');
+
+		$this->assertSame($oldNextKey, $this->appConfigStrings[JwkService::PEM_SIG_KEY_SETTINGS_KEY]);
+		$this->assertSame($oldNextCreatedAt, $this->appConfigInts[JwkService::PEM_SIG_KEY_CREATED_AT_SETTINGS_KEY]);
+		$this->assertNotSame($oldNextKey, $this->appConfigStrings[JwkService::PEM_NEXT_SIG_KEY_SETTINGS_KEY]);
+		$this->assertGreaterThan($oldNextCreatedAt, $this->appConfigInts[JwkService::PEM_NEXT_SIG_KEY_CREATED_AT_SETTINGS_KEY]);
+
+		$jwks = $this->jwkService->getJwks();
+		$this->assertSame('sig_key_' . $oldNextCreatedAt, $jwks[0]['kid']);
+		$this->assertNotSame($jwks[0]['kid'], $jwks[1]['kid']);
+	}
 }