The other comments are all right, I just want to rephrase this is bit. Neither quotes are wrong, per se. This part: > Maybe there's something I'm not understa

The other comments are all right, I just want to rephrase this is bit. Neither quotes are wrong, per se. This part: > Maybe there's something I'm not understanding, but I thought the point of DH was you could exchange something even when other people are listening DH does protect you against people listening. It doesn't help if they can actively change what you hear. Passive eavesdroppers are thwarted, but an active MitM attack is not, which is where authenticating the other end comes in. The common example of DH I've seen is that you can establish a secret key with someone in a crowded room, with everyone overhearing your conversation. In that example, our "authentication" is that we can visually see the other person and we recognize them (or at least, we want to communicate with that person).