This page is part of a ground up introduction to libp2p’s building blocks. It’s very good, even if incomplete. The peer-id section I believe could use a small addition.
https://docs.libp2p.io/concepts/peer-id/
Each libp2p peer controls a private key, which it keeps secret from all other peers. Every private key has a corresponding public key, which is shared with other peers.
Together, the public and private key (or “key pair”) allow peers to establish secure communication channels with each other.
The only hint of how communications are actually secured is through the link. Even assuming the link sent the reader to a good explanation, its worth adding just a single, simple phrase which explains how public/private key pairs secure communications, since this page already goes to the trouble to introduce them and assumes the reader knows what a hash is.
Something like:
Each libp2p peer controls a private key, which it keeps secret from all other peers. Every private key has a corresponding public key, which is shared with other peers.
Together, the public and private key (or “key pair”) allow peers to establish channels with each other.
When communicating with a client specified by their PeerId, each peer can ask for proof that the other’s PeerId belongs to them by requesting cryptographic proof which can only be satisfied through knowledge private key corresponding to the PeerId. " This enables secure communication [new users can only post two link] channels between clients.