sshauthorizedkeys2

authorized_keys2 is a file used by the OpenSSH server to manage SSH public key authentication. It is an alternative to the standard authorized_keys file. The primary difference lies in how it stores and interprets the public key data. Instead of storing the entire public key on a single line, authorized_keys2 can store multiple public keys, each on a separate line, potentially with associated options. This format was intended to offer greater flexibility and organization for managing a large number of authorized keys. However, the authorized_keys2 file is generally considered deprecated and less commonly used in modern OpenSSH configurations. The standard authorized_keys file is the widely adopted and recommended method for managing SSH public key authentication. When a client attempts to connect using public key authentication, the SSH server checks the authorized_keys file (or authorized_keys2 if configured) in the user's .ssh directory for a matching public key. If a match is found and any specified options are satisfied, the connection is granted without requiring a password.