title: How does the man in the middle attack work in Diffie–Hellman?
body: <p>I'm having doubts about the mechanics of a man in the middle attack during a Diffie–Hellman key exchange. I have heard that it can happen during the key agreement communication. But in the presence of CA (Certificate Authority) the receiver can authenticate the sender as he received the sender's public key. Therefore, how is a man in the middle attack possible?</p>