}
    public RC4(byte[] key)
    {
        init(key, 0, key.length);
    }

    public void init(byte[] key, int ki, int klen)
    {
        s = new byte[256];

        for (i = 0; i < 256; i++)
            s[i] = (byte)i;

        for (i = j = 0; i < 256; i++) {
            j = (j + key[ki + i % klen] + s[i]) & 0xff;
            byte t = s[i];
            s[i] = s[j];
            s[j] = t;
        }