Question

Basically, I’m trying to have an encrypted data flow between Java client and a c# server.
Before jumping into the deep water of having a multi platform encryption working, I’m trying to make a simple encryption app but I’m stuck at the very beginning.

I have the following simple code:

String text = "hello";
        KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
        kpg.initialize(2048);
        KeyPair kp = kpg.genKeyPair();
        Key publicKey = kp.getPublic();
        Key privateKey = kp.getPrivate();

        Cipher cipher = Cipher.getInstance("RSA/ECB/NoPadding");
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        byte[] cipherData = cipher.doFinal(text.getBytes());

        cipher = Cipher.getInstance("RSA/ECB/NoPadding");
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        byte[] textData = cipher.doFinal(text.getBytes());

        String decrypted = new String(textData);
        System.out.println(decrypted);

No exception is thrown but I don’t get the original “hello” text after the decryption.
Any ideas?
10x a lot

Answer 1

This looks fishy:

byte[] textData = cipher.doFinal(text.getBytes());

Did you mean:

byte[] textData = cipher.doFinal(cipherData);