(PECL ssh2 >= 0.10)
ssh2_publickey_init — Initialize Publickey subsystem
Request the Publickey subsystem from an already connected SSH2 server.
The publickey subsystem allows an already connected and authenticated client to manage the list of authorized public keys stored on the target server in an implementation agnostic manner. If the remote server does not support the publickey subsystem, the ssh2_publickey_init() function will return FALSE.
Returns an SSH2 Publickey Subsystem resource for use with all other ssh2_publickey_*() methods or FALSE on failure.
Note: The public key subsystem is used for managing public keys on a server to which the client is already authenticated. To authenticate to a remote system using public key authentication, use the ssh2_auth_pubkey_file() function instead.