libssh2 is a library implementing the SSH2 protocol as defined by
Internet Drafts: SECSH-TRANS(22), SECSH-USERAUTH(25), SECSH-CONNECTION(23),
SECSH-ARCH(20), SECSH-FILEXFER(06)*, SECSH-DHGEX(04), and SECSH-NUMBERS(10).

WWW: http://libssh2.sourceforge.net/