AES encryption is incompatible with java AES decryption - always gives BadPaddingException

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What steps will reproduce the problem?
1. Use as3crypto AES to encrypt anything
2. try and decrypt it using javax.crypo 
3. You will always get: javax.crypto.BadPaddingException: Given final block not 
properly padded

Flash code snippets:

public function TestEncryption()
    {
    var encryptedBytes:ByteArray;   
    encryptedBytes = encrypt("1234567890123456");
    }
public static var KEY:ByteArray = 
Hex.toArray("faf579668b4bb03be0732eb0a42a7ebe");

public static function encrypt(data:String):ByteArray {
    var AES:AESKey = new AESKey(KEY);
    var dataByteArray:ByteArray =new ByteArray();
    trace("outgoing messsage [" + data + "]");
    dataByteArray.writeUTFBytes(data);
    trace("before encryption [" + Hex.fromArray(dataByteArray, true) + "]");
    trace("before encryption [" + Hex.fromArray(dataByteArray, false) + "]");

    var blocks:uint = dataByteArray.length / 16 
    // Pad out the array to exactly 16 byte blocks.
    var remainder:uint = dataByteArray.length % 16
    if ( remainder > 0)  {
    blocks ++;
    dataByteArray.length = 16*(blocks); // this right fills with \00
    }

    trace("before encryption after padding [" + Hex.fromArray(dataByteArray, true) + "]");
    trace("before encryption after padding [" + Hex.fromArray(dataByteArray, false) + "]");

    for (var block:uint=0; block < blocks; block++) {
    AES.encrypt(dataByteArray, block*16);
    }

    trace("after encryption  [" + Hex.fromArray(dataByteArray, true) + "]");
    trace("after encryption  [" + Hex.fromArray(dataByteArray, false) + "]");

    return dataByteArray;
} // encrypt()


This produces:
outgoing messsage [1234567890123456]
before encryption [31:32:33:34:35:36:37:38:39:30:31:32:33:34:35:36]
before encryption [31323334353637383930313233343536]
before encryption after padding 
[31:32:33:34:35:36:37:38:39:30:31:32:33:34:35:36]
before encryption after padding [31323334353637383930313233343536]
after encryption  [12:67:3b:79:94:50:4a:71:04:6c:86:58:03:15:5c:e4]
after encryption  [12673b7994504a71046c865803155ce4]

So the encrpted string is (hex): 12673b7994504a71046c865803155ce4

Java code snippets:

byte[] messageBytes = CryptUtils.hexToBytes(message);
String result;

public static void main(String[] args) throws NoSuchAlgorithmException, 
NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, 
BadPaddingException {

    byte[] messageBytes = CryptUtils.hexToBytes("12673b7994504a71046c865803155ce4");
    String strKeyHex="faf579668b4bb03be0732eb0a42a7ebe";
    byte[] raw = CryptUtils.hexToBytes(strKeyHex);
    KeyGenerator kgen = KeyGenerator.getInstance("AES");
    kgen.init(128); // 192 and 256 bits may not be available
    SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.DECRYPT_MODE, skeySpec);

    byte[] decrypted = cipher.doFinal(messageBytes);
}

public static byte[] hexToBytes(String hex) {
    byte[] bts = new byte[hex.length() / 2];
    for (int i = 0; i < bts.length; i++) {
       bts[i] = (byte) Integer.parseInt(hex.substring(2 * i, 2 * i + 2), 16);
    }
    return bts;
}

This always generates:
Exception in thread "main" javax.crypto.BadPaddingException: Given final block 
not properly padded
    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
    at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..)
    at javax.crypto.Cipher.doFinal(DashoA13*..)
    at com.skillkash.ge.api.TestEncrypt.decryptBytes(TestEncrypt.java:53)
    at com.skillkash.ge.api.TestEncrypt.main(TestEncrypt.java:32)algo: AES

Original issue reported on code.google.com by hob...@gmail.com on 9 Dec 2010 at 8:11