def ConstantAddition(s, t, scheme):
    """
    ConstantAddition function from LowMC spec.

    :params s:  state
    :params bs: round constants
    :params t:  round
    :param scheme: lowmc parametrization + constants
    """
    return [s[i] ^ scheme['b'][t-1][i] for i in range(scheme['blocksize'])]