(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 或者在失败时返回 FALSE.
Note: 公钥子系统用于管理服务器到已被认证的客户端的公钥。要用公钥认证方法来认证远程系统，应使用 ssh2_auth_pubkey_file() 函数。