C-source for diffie-hellman?

[Sameer]

	I was just talking with a friend, and I think it would be
pretty good for medium-level security on irc to hack up something do
that /dcc does diffie-hellman key exchange, and maybe triple-des or
something.
	Is there some available C-source which would help? (I guess I
should get the Schneier book.. But urgh! $50 on a "starving-student"
budget is quite a bit.)