void shiftRows(unsigned char* State)
{
    unsigned char holder[16];
    copyM(State, holder);

    // Rotate 1
    State[1] = holder[5];
    State[5] = holder[9];
    State[9] = holder[13];
    State[13] = holder[1];

    // Rotate 2
    State[2] = holder[10];
    State[6] = holder[14];
    State[10] = holder[2];
    State[14] = holder[6];

    // Rotate 3
    State[3] = holder[15];
    State[7] = holder[3];
    State[11] = holder[7];
    State[15] = holder[11];
}