Bob computes gxy mod n as (gymod n)x mod n
Why do we care about Diffie-Hellmen
Simply stated, if you are involved in any sort of Virtual Private Network (VPN), you are probably using Diffie-Hellman, even if you didn't realize it. If that VPN is operating on the IPSec standard, then Diffie-Hellman is certainly in use. To follow the standards trail for key management in IPSec, we begin with the overall framework called Internet Security Association and Key Management Protocol (ISAKMP; see RFC 2408). Within that framework is the Internet Key Exchange (IKE) protocol (see RFC 2401). IKE relies on yet another protocol known as OAKLEY and it uses Diffie-Hellman as described in RFC 2412. It is an admittedly long trail to follow, but the result is that Diffie-Hellman is, indeed, a part of the IPSec standard.
(Figure 1) Diffie-Hellman Key Exchange
Here are a few links to some sites of
interest. Diffie-Hellman PGP RSA DES MD5
Here are a few links to some sites of interest.