CryChat/crychat/server/util/CeasarChipher.java

package server.util;

public class CeasarChipher {

    public static byte[] encrypt(byte[] x) {
        for (int i = 0; i < x.length; ++i) {
            x[i] = (byte) ((x[i] + 3) % 256);
        }
        return x;
    }

    public static byte[] decrypt(byte[] x) {
        for (int i = 0; i < x.length; ++i) {
            x[i] = (byte) ((x[i] + 253) % 256);
        }
        return x;
    }
}