def KeyAddition(s, rks, t, scheme, in_place=False):
    """
    KeyAddition function from LowMC spec.

    :params s:  state
    :params rks: round keys
    :params t:  round
    :param scheme: lowmc parametrization + constants
    """
    if in_place:
        return [s[i] ^ rks[i] for i in range(scheme['blocksize'])]
    else:
        return [s[i] ^ rks[t][i] for i in range(scheme['blocksize'])]