How Encrypt with AES CBC Zero Padding in Javascript and decrypt with Java

Question

I need encrypt in Javascript and Decrypt in Java but when i encrypt in Java the text is diferent, i used a diferent script but same algorithm, AES-128 CBC Zero Padding.

This is for Javascript and Java 7 in Intellij IDEA

Javascript:

   var message = "3258";
   var key = "CLAVE00000000000";
   var iv  = "VECTOR0000000000";

   var ciphertext = CryptoJS.AES.encrypt(message, key,  {iv: iv, padding: CryptoJS.pad.ZeroPadding, mode: CryptoJS.mode.CBC});
   alert(ciphertext.toString());

   var decrypt = CryptoJS.AES.decrypt(ciphertext, key, {iv: iv, padding: CryptoJS.pad.ZeroPadding, mode: CryptoJS.mode.CBC});
   alert(CryptoJS.enc.Utf8.stringify(decrypt).toString());

Java:

KeyGenerator keyGenerator = KeyGenerator.getInstance(ALGORITHM);
keyGenerator.init(AES_128);

String key = "CLAVE00000000000";
String IV = "VECTOR0000000000";
System.out.println("1. Message to Encrypt: " + new String(message, StandardCharsets.UTF_8));

byte[] cipherText = encrypt(key, IV, message);
System.out.println("2. Encrypted Text: " + Base64.getEncoder().encodeToString(cipherText));

byte[] decryptedString = decrypt(key, IV, cipherText);
System.out.println("3. Decrypted Message : " + new String(decryptedString));

I expect the cipher text identical in Javascript or in Java, but the values are diferent

In Javascript is: U2FsdGVkX1/3H3/VO8b5gjCk3XZfXkSK9JpgmPGYjtk= — Jose Guerra, Apr 22 '19 at 14:43
Same algorithm = same result for the same input. Please show your more of Java code, it is missing the must relevant methods. — Victor, Apr 22 '19 at 18:16

Topaco · Accepted Answer · 2019-04-22T18:35:45.630

In the JavaScript-code key and iv have to be passed as WordArrays. For this purpose CryptoJS provides conversion functions:

var key = CryptoJS.enc.Latin1.parse("CLAVE00000000000");
var iv = CryptoJS.enc.Latin1.parse("VECTOR0000000000");

If the key is passed as a string (as it is the case in the posted code), it is treated as a passphrase and used to derive a key and IV (see here, section The Cipher Input).

Furthermore, in the JavaScript-code Zero-Byte-Padding must be replaced by Pkcs7-Padding (padding: CryptoJS.pad.Pkcs7 instead of padding: CryptoJS.pad.ZeroPadding) in the encrypt- and decrypt-call.

Then the encryption of the JavaScript-code corresponds to that of the Java-code (sEAtASy0J3+Ya3g+Afcj3Q== for the used message, key and IV).

The replacing of the padding is a guess because the encrypt- and decrypt-methods of the Java-code have not been posted, so that a direct check is not possible. However, with regard to the same encryption when switching to Pkcs7, this should be true.

How Encrypt with AES CBC Zero Padding in Javascript and decrypt with Java

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