Defined in 802.11i p.49

def _michael_b(m_l, m_r):
    """Defined in 802.11i p.49"""
    m_r = m_r ^ _rotate_left32(m_l, 17)
    m_l = (m_l + m_r) % 2**32
    m_r = m_r ^ _XSWAP(m_l)
    m_l = (m_l + m_r) % 2**32
    m_r = m_r ^ _rotate_left32(m_l, 3)
    m_l = (m_l + m_r) % 2**32
    m_r = m_r ^ _rotate_right32(m_l, 2)
    m_l = (m_l + m_r) % 2**32
    return m_l, m_r