Which of the following describes how a user's public key is used during SSH authentication?

The user's public key is not used to hash a password during SSH public key authentication, which bypasses password usage.

When a user attempts to authenticate via SSH with a private key, the server checks if the corresponding public key is present in the user's `~/.ssh/authorized_keys` file. If found, the server challenges the client by encrypting a random string with the public key, and the client proves its identity by successfully decrypting it with the private key.

While public key authentication replaces password authentication, the public key itself is not a direct substitute for a password; instead, it's part of a cryptographic challenge-response mechanism involving both keys.

The user's public key is part of the authentication process and initial key exchange for secure communication, but session keys generated during handshake primarily encrypt the ongoing communication between client and server.