Fix 3DES encryption with 64- and 128-bit keys

Julian Kwieciński · Julian Kwieciński · commit 150d88df6706 · 2019-04-02T15:14:00.000+02:00
diff --git a/src/tripledes.js b/src/tripledes.js
@@ -712,11 +712,20 @@
             // Shortcuts
             var key = this._key;
             var keyWords = key.words;
+            // Make sure the key length is valid (64, 128 or >= 192 bit)
+            if (keyWords.length !== 2 && keyWords.length !== 4 && keyWords.length < 6) {
+                throw new Error('Invalid key length - 3DES requires the key length to be 64, 128, 192 or >192.');
+            }
+
+            // Extend the key according to the keying options defined in 3DES standard
+            var key1 = keyWords.slice(0, 2);
+            var key2 = keyWords.length < 4 ? keyWords.slice(0, 2) : keyWords.slice(2, 4);
+            var key3 = keyWords.length < 6 ? keyWords.slice(0, 2) : keyWords.slice(4, 6);
 
             // Create DES instances
-            this._des1 = DES.createEncryptor(WordArray.create(keyWords.slice(0, 2)));
-            this._des2 = DES.createEncryptor(WordArray.create(keyWords.slice(2, 4)));
-            this._des3 = DES.createEncryptor(WordArray.create(keyWords.slice(4, 6)));
+            this._des1 = DES.createEncryptor(WordArray.create(key1));
+            this._des2 = DES.createEncryptor(WordArray.create(key2));
+            this._des3 = DES.createEncryptor(WordArray.create(key3));
         },
 
         encryptBlock: function (M, offset) {
diff --git a/test/tripledes-test.js b/test/tripledes-test.js
@@ -62,6 +62,39 @@ YUI.add('algo-tripledes-test', function (Y) {
             Y.Assert.areEqual(expectedIv, iv.toString());
         },
 
+        test64BitKey: function() {
+            var message = C.enc.Hex.parse('00112233445566778899aabbccddeeff');
+            var key = C.enc.Hex.parse('0011223344556677');
+            var extendedKey = C.enc.Hex.parse('001122334455667700112233445566770011223344556677')
+            
+            var output1 = C.TripleDES.encrypt(message, key, { mode: C.mode.ECB }).toString();
+            var output2 = C.TripleDES.encrypt(message, extendedKey, { mode: C.mode.ECB }).toString();
+
+            Y.Assert.areEqual(output1, output2);
+        },
+
+        test128BitKey: function() {
+            var message = C.enc.Hex.parse('00112233445566778899aabbccddeeff');
+            var key = C.enc.Hex.parse('00112233445566778899aabbccddeeff');
+            var extendedKey = C.enc.Hex.parse('00112233445566778899aabbccddeeff0011223344556677')
+            
+            var output1 = C.TripleDES.encrypt(message, key, { mode: C.mode.ECB }).toString();
+            var output2 = C.TripleDES.encrypt(message, extendedKey, { mode: C.mode.ECB }).toString();
+
+            Y.Assert.areEqual(output1, output2);
+        },
+
+        test256BitKey: function() {
+            var message = C.enc.Hex.parse('00112233445566778899aabbccddeeff');
+            var key = C.enc.Hex.parse('00112233445566778899aabbccddeeff0112233445566778899aabbccddeeff0');
+            var truncatedKey = C.enc.Hex.parse('00112233445566778899aabbccddeeff0112233445566778')
+            
+            var output1 = C.TripleDES.encrypt(message, key, { mode: C.mode.ECB }).toString();
+            var output2 = C.TripleDES.encrypt(message, truncatedKey, { mode: C.mode.ECB }).toString();
+
+            Y.Assert.areEqual(output1, output2);
+        },
+
         testHelper: function () {
             // Save original random method
             var random = C.lib.WordArray.random;
