Need help converting c# encryption to java (android) encryption for cross compatibility

Vote count:

0

I've been attempting to convert this class (been using it in my c# app for a couple years now) to java for use in an android application: http://ift.tt/1z2KyTy

Some areas where I am having trouble is things like MemoryStream, CryptoStream, and more specifically:

//C# CODE
//Grab IV from message
var iv = new byte[ivLength];
Array.Copy(encryptedMessage, nonSecretPayloadLength, iv, 0, iv.Length);

using (var decrypter = aes.CreateDecryptor(cryptKey, iv))
using (var plainTextStream = new MemoryStream())
{
    using (var decrypterStream = new CryptoStream(plainTextStream, decrypter, CryptoStreamMode.Write))
    using (var binaryWriter = new BinaryWriter(decrypterStream))
    {
        //Decrypt Cipher Text from Message
        binaryWriter.Write(
            encryptedMessage,
            nonSecretPayloadLength + iv.Length,
            encryptedMessage.Length - nonSecretPayloadLength - iv.Length - sentTag.Length
        );
    }
    //Return Plain Text
    return plainTextStream.ToArray();
}

I am not quite sure what the java equivalent to CryptoStream or MemoryStream.

What I've got so far (pertaining to this code example, not the whole class)

//Grab IV from message
byte[] iv = new byte[ivLength];
System.arraycopy(encryptedMessage, nonSecretPayloadLength, iv, 0, iv.length);

Cipher aes = Cipher.getInstance("AES/CBC/PKCS7Padding");
// MISSING: create IvParameterSpec
IvParameterSpec ivSpec = new IvParameterSpec(iv);
iv = ivSpec.getIV();

aes.init(Cipher.DECRYPT_MODE, secretKeySpecy, ivSpec);

//byte[] decoded = aes.doFinal(Base64.decodeBase64(encryptedMessage));

ByteArrayOutputStream decrypterStream = new ByteArrayOutputStream();
DataOutputStream binaryWriter = new DataOutputStream(decrypterStream);

        binaryWriter.write(
                encryptedMessage,
                nonSecretPayloadLength + iv.length,
                encryptedMessage.length - nonSecretPayloadLength - iv.length - sentTag.length
        );

If anyone could give me some pointers/help id be most grateful.

asked 1 min ago

FanaticNinja

1

Need help converting c# encryption to java (android) encryption for cross compatibility