diff --git a/src/main.js b/src/main.js
index 1780802..971cb1d 100644
--- a/src/main.js
+++ b/src/main.js
@@ -351,8 +351,10 @@ crypto = {
       sbytes: sbytes,
     }
   },
-  verify: function (bytes, sig, pk) {
-    return library.sodium.crypto_sign_verify_detached(sig, utility.hex2buf(bytes), utility.b58cdecode(pk, prefix.edpk));
+  verify: function (bytes, sig, pk, wm) {
+    var bb = utility.hex2buf(bytes);
+    if (typeof wm != 'undefined') bb = utility.mergebuf(wm, bb);
+    return library.sodium.crypto_sign_verify_detached(sig, library.sodium.crypto_generichash(32, bb), utility.b58cdecode(pk, prefix.edpk));
   },
 };
 node = {
diff --git a/test/test.js b/test/test.js
index ad01583..d9b5c00 100644
--- a/test/test.js
+++ b/test/test.js
@@ -61,6 +61,7 @@ describe('main', () => {
   describe('crypto', () => {
     const main = require('../src/main');
     const crypto = main.eztz.crypto;
+    const watermark = main.eztz.watermark;
 
     test('generateMnemonic', () => {
       const string = crypto.generateMnemonic();
@@ -124,6 +125,20 @@ describe('main', () => {
       // expect(typeof keys.edsig).toBe('string');
       // expect(typeof keys.sbytes).toBe('string');
     });
+
+    test('sign and verify', () => {
+      const keys = crypto.generateKeys('', '');
+      const bytes = "20aa4d05fecad06b193f909564d4fcfd90e4cd01a6e13298329d802420dff96a9be42bcbe4739a783c117fa13fb42cf007cb67054a12fb977aca95c442745805";
+      let sign = crypto.sign(bytes, keys.sk);
+      expect(crypto.verify(bytes, sign.sig, keys.pk)).toBe(true);
+    });
+
+    test('sign and verify with watermark', () => {
+      const keys = crypto.generateKeys('', '');
+      const bytes = "20aa4d05fecad06b193f909564d4fcfd90e4cd01a6e13298329d802420dff96a9be42bcbe4739a783c117fa13fb42cf007cb67054a12fb977aca95c442745805";
+      let sign = crypto.sign(bytes, keys.sk, watermark.generic);
+      expect(crypto.verify(bytes, sign.sig, keys.pk, watermark.generic)).toBe(true);
+    });
   });
 
   describe('node', () => {