PCR revocation security: lazy enforcement, type-bound PCRs

contracts/solidity/TEEInferenceVerifier.sol

@@ -6,7 +6,25 @@ import "./precompiles/tee/ITEEVerifier.sol";
 import "@openzeppelin/contracts/access/AccessControl.sol";
 
 /// @title TEEInferenceVerifier - Verification for TEE-signed inference outputs
-/// @notice Reads TEE public keys from TEERegistry and verifies RSA-PSS signatures with timestamp validation.
+/// @notice Stateless verifier that confirms an AI inference output was produced by a
+///         registered, active TEE within an acceptable time window.
+///
+/// @dev ## How It Works
+///
+///  When a TEE runs an inference, it signs `keccak256(inputHash || outputHash || timestamp)`
+///  with its RSA-PSS private key. Any party (settlement relay, on-chain consumer, etc.) can
+///  then call `verifySignature` to confirm authenticity. The check is three-fold:
+///
+///    1. **TEE status** — the TEE must be active in the `TEERegistry`.
+///    2. **Timestamp bounds** — the signed timestamp must be within
+///       `[block.timestamp - MAX_INFERENCE_AGE, block.timestamp + FUTURE_TOLERANCE]`
+///       to prevent replay of stale results and reject clock-skewed signatures.
+///    3. **Cryptographic proof** — the RSA-PSS signature is verified against the TEE's
+///       on-chain public key via the 0x900 precompile.
+///
+///  The contract is intentionally read-only (no state mutations in `verifySignature`) so
+///  it can be called from view contexts and composed freely by downstream contracts like
+///  `InferenceSettlementRelay`.
 contract TEEInferenceVerifier is AccessControl {
 
     // ============ Constants ============

contracts/solidity/TEERegistry.json

@@ -61,6 +61,11 @@
       "name": "NotTEEOwner",
       "type": "error"
     },
+    {
+      "inputs": [],
+      "name": "PCRAlreadyExists",
+      "type": "error"
+    },
     {
       "inputs": [],
       "name": "PCRExpired",
@@ -71,6 +76,11 @@
       "name": "PCRNotApproved",
       "type": "error"
     },
+    {
+      "inputs": [],
+      "name": "PCRTypeMismatch",
+      "type": "error"
+    },
     {
       "inputs": [],
       "name": "TEEAlreadyExists",
@@ -118,6 +128,12 @@
           "name": "pcrHash",
           "type": "bytes32"
         },
+        {
+          "indexed": true,
+          "internalType": "uint8",
+          "name": "teeType",
+          "type": "uint8"
+        },
         {
           "indexed": false,
           "internalType": "string",
@@ -136,6 +152,12 @@
           "internalType": "bytes32",
           "name": "pcrHash",
           "type": "bytes32"
+        },
+        {
+          "indexed": false,
+          "internalType": "uint256",
+          "name": "gracePeriod",
+          "type": "uint256"
         }
       ],
       "name": "PCRRevoked",
@@ -399,14 +421,9 @@
           "type": "string"
         },
         {
-          "internalType": "bytes32",
-          "name": "previousPcrHash",
-          "type": "bytes32"
-        },
-        {
-          "internalType": "uint256",
-          "name": "gracePeriod",
-          "type": "uint256"
+          "internalType": "uint8",
+          "name": "teeType",
+          "type": "uint8"
         }
       ],
       "name": "approvePCR",
@@ -429,6 +446,11 @@
           "name": "active",
           "type": "bool"
         },
+        {
+          "internalType": "uint8",
+          "name": "teeType",
+          "type": "uint8"
+        },
         {
           "internalType": "uint256",
           "name": "approvedAt",
@@ -984,6 +1006,11 @@
           "internalType": "bytes32",
           "name": "pcrHash",
           "type": "bytes32"
+        },
+        {
+          "internalType": "uint256",
+          "name": "gracePeriod",
+          "type": "uint256"
         }
       ],
       "name": "revokePCR",