# What is straight line black box reduction?

I understand the notion of black box reduction. But what is straight line black box reduction?

So, assuming (as an example) that the protocol has the corrupted party receiving $5$ messages, then the straight-line black-box reduction can/will give the adversary the messages $m_1,m_2,m_3,m_4,m_5$. In that order; and in that order only.