Key transfer in P2P networks

Question

Encryption

We have two clients on a p2p network that need to exchange keys without a third party. Keys must be used for a long time (i.e. within more than one session). Actually, the question is: how to organize it?

Answer 1

For a secure (man-in-the-middle) key exchange, clients must sign all their messages. In order for the signature to be verified, the other party must know the public key. To be sure of the validity of the public key, it in turn must be signed by someone we trust. Usually a public key server is used for this, but in your case you need to think.
My blog (see profile) has several articles on p2p and public key cryptography. Read it, it may help to come across the right thoughts. Just remember that protocol-level errors are very expensive to fix. So it makes sense to discuss any of your “brilliant” thoughts with at least a couple of understanding people.

Answer 2

It seems to me to look towards SSL, public key generation by MAC.