Add support for DSA authentication in SSH2, following clever ideas

[u/mdw/putty] / doc / pubkey.but

\versionid $Id: pubkey.but,v 1.5 2001/09/22 20:52:21 simon Exp $

\# FIXME: passphrases, examples (e.g what does a key for pasting into
\# authorized_keys look like?), index entries, links.

\C{pubkey} Using public keys for SSH authentication

\H{pubkey-intro} Public key authentication - an introduction

Public key authentication is an alternative means of identifying
yourself to a login server, instead of typing a password. It is more
secure and more flexible, but more difficult to set up.

In conventional password authentication, you prove you are who you
claim to be by proving that you know the correct password. The only
way to prove you know the password is to tell the server what you
think the password is. This means that if the server has been
hacked, or \e{spoofed} (see \k{gs-hostkey}), an attacker can learn
your password.

Public key authentication solves this problem. You generate a \e{key
pair}, consisting of a public key (which everybody is allowed to
know) and a private key (which you keep secret and do not give to
anybody). The private key is able to generate \e{signatures}.