SSH2 provides bindings to libssh2 library which provide access to resources (remote exec, shell, file transfer, tunneling) on a remote machine using a secure cryptographic transport. SSH2 is a more efficient, secure, & portable version of SSH that includes SFTP, which functions similar to FTP, but has SSH2 encryption enabled. It works on port 22 instead of 21.
You can validate multiple identities via public key encryption instead of using passwords to authenticate remote hosts.
Installation of SSH2 is very simple and requires not more than 2 commands on a linux distro.
# yum install libssh2-devel
# pecl install -f ssh2