AES encryption/decryption from c# to java

Question

I'm using AES encryption/decryption algorithm in my application.

On the server side I use c# to encrypt/decrypt the data.

And on client side(android) I use java to decrypt the data.

C# encryption/decryption code

    static readonly string PasswordHash = "52";

    static readonly string SaltKey = "dfkjsadfinewdfadsfkmeoinmsdflksdflk";

    static readonly string VIKey = "@EUBRHDFBFG8867";

public static string Encrypt(string plainText)
    {
        byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);

        byte[] keyBytes = new Rfc2898DeriveBytes(PasswordHash,Encoding.ASCII.GetBytes(SaltKey)).GetBytes(256 / 8);

        var symmetricKey = new RijndaelManaged() { Mode = CipherMode.CBC, Padding =PaddingMode.Zeros };

        var encryptor = symmetricKey.CreateEncryptor(keyBytes,Encoding.ASCII.GetBytes(VIKey));
        byte[] cipherTextBytes;

        using (var memoryStream = new MemoryStream())
        {
            using (var cryptoStream = new CryptoStream(memoryStream, encryptor,CryptoStreamMode.Write))
            {
                cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
                cryptoStream.FlushFinalBlock();
                cipherTextBytes = memoryStream.ToArray();
                cryptoStream.Close();
            }
            memoryStream.Close();
        }           
       return Convert.ToBase64String(cipherTextBytes);
    }

    public static string Decrypt(string encryptedText)
    {
        byte[] cipherTextBytes = Convert.FromBase64String(encryptedText);

        byte[] keyBytes = new Rfc2898DeriveBytes(PasswordHash,Encoding.ASCII.GetBytes(SaltKey)).GetBytes(256 / 8);

        var symmetricKey = new RijndaelManaged() { Mode = CipherMode.CBC, Padding =PaddingMode.None }

        var decryptor = symmetricKey.CreateDecryptor(keyBytes,Encoding.ASCII.GetBytes(VIKey));

        var memoryStream = new MemoryStream(cipherTextBytes);

        var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read);

        byte[] plainTextBytes = new byte[cipherTextBytes.Length];

        int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);

        memoryStream.Close();
        cryptoStream.Close();

        return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount).TrimEnd("\0".ToCharArray());
    }

Java Decryption method

public String decrypt(String dataToDecrypt) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, InvalidKeySpecException, IllegalBlockSizeException, BadPaddingException, InvalidAlgorithmParameterException, UnsupportedEncodingException 
{

    byte[] encryptedCombinedBytes = Base64.decodeBase64(dataToDecrypt.getBytes());

    String saltKey = "dfkjsadfinewdfadsfkmeoinmsdflksdflk";
    String password = "52";
    String IVKey = "@EUBRHDFBFG8867";

    PBKDF2Parameters p = new PBKDF2Parameters("HmacSHA256", "ASCII", saltKey.getBytes(), 8);

    byte[] mEncryptedPassword = new PBKDF2Engine(p).deriveKey(password);


    byte[] ivbytes = Arrays.copyOfRange(IVKey.getBytes(), 0, 16);

    SecretKeySpec mSecretKeySpec = new SecretKeySpec(mEncryptedPassword, "AES");

    Cipher mCipher = Cipher.getInstance("AES/CBC/NoPadding");

    mCipher.init(Cipher.DECRYPT_MODE, mSecretKeySpec, new IvParameterSpec(ivbytes));

    byte[] encryptedTextBytes = Arrays.copyOfRange(encryptedCombinedBytes, 16, encryptedCombinedBytes.length);

    byte[] decryptedTextBytes = mCipher.doFinal(encryptedTextBytes);

    return new String(decryptedTextBytes, "UTF-8");
}

C# decryption method works fine and give the result string.

I cannot figure out the problem in Java decryption code. It runs and give me some garbage value.

EDIT

1. I can not edit anything on the server side.I just have to replicate the decryption in java decryption.
2. I dont know how to use passwordHash, saltKey and IVkey

Answer 1

First of all, you've switched the password and the salt around.

Second, PBKDF2 uses HMAC/SHA-1 as default. As far as I know that's also the default for Rfc2898DeriveBytes:

Implements password-based key derivation functionality, PBKDF2, by using a pseudo-random number generator based on HMACSHA1.

You should also never call getBytes without specifying the character set in Java, but this is probably not an issue for your current runtime.

---

These are comments on the code only; do not use CBC over network connections without integrity/authenticity protection.