B = HH(B, C, D, A, X[15], 15);

        context[0] += A;
        context[1] += B;
        context[2] += C;
        context[3] += D;
    }

    // The basic MD4 atomic functions.

    private int FF (int a, int b, int c, int d, int x, int s) {
        int t = a + ((b & c) | (~b & d)) + x;
        return t << s | t >>> (32 - s);
    }