Question

In my app I’ve used AES algorithm for WLAN communications, but now I’m transferring data through bluetooth I would like to get some security. The problem is that AES is too much “heavy” because it gives me blocks of more than 100 bytes – when I’m transferring less than 10 bytes – I would like to use something lighter, if it’s possible.

Anyone knows a better solution?

Answer 1

Use AES with 128-bit blocks. That’s 16 bytes. Initializing for encryption goes like this:

//Generate a key
KeyGenerator KeyGen = KeyGenerator.getInstance("AES");
KeyGen.init(128);
SecretKey Key = KeyGen.generateKey();

//Generate init vector
SecureRandom rng = SecureRandom.getInstance("SHA1PRNG");
byte [] IV = new byte[16];
rng.nextBytes(IV);

//Initialize the encryptor
Cipher ci = Cipher.getInstance("AES/CBC/NoPadding"); //The spec might be different!
ci.init(Cipher.ENCRYPT_MODE, Key, new IvParameterSpec(IV));

RC4 has known weaknesses.