ssh protocol

[Matthew Ghio]

Tatu Ylonen <ylo at cs.hut.fi> wrote:
> The basic idea behind the protocol goes roughly like this:
>   1. Exchange session keys using Diffie-Hellman
>   2. Each side sends a signature of the Diffie-Hellman exchange (the
>      signature can be with any of a number of algorithms; RSA and
>      Elliptic Curve systems have been defined).

I've been playing with the cryptotcp program available from utopia..  It
has some bugs but works pretty well, if you don't mind waiting 20-30
seconds at the beginning.  It does a Diffie-Hellman exchange and 3DES over
telnet.  How hard would it be to add some sort of authentication to this
program?