SSH Version 1, developed in 1995, is being phased out in favor
of SSH Version 2, currently (2001) being standardized by the
IETF's Secure Shell Working Group. Other important SSH-related
links include: SSH operates over TCP. In its simplest mode of
operation, it connects to a server, negotiates a shared secret
key using Diffie Hellman, then begins encrypting the session
(typically using the Blowfish cipher). A username and password
are passed over the encrypted session and, if authenticated, the
server starts a command shell over the encrypted session. Thus,
in its simplest use, SSH represents a more secure alternative to
TELNET. I particularly like to use the MindTerm Java applet,
which allows encrypted logins from systems that don't have SSH
clients - all you need is a web browser capable of running Java
applets. In more advanced usage, ssh allows the creation of RSA
or DSA asymmetric key pairs. The private key is stored in an
identity file, possibly encrypted using a passphrase. The public
key can be copie