Security Issues in the Diffie-Hellman Key Agreement Protocol

Diffie-Hellman key agreement protocol [27] implementations have been plagued by serious security flaws. The attacks can be very subtle and, more often than not, haven’t been taken into account by protocol designers. In this paper we attempt to provide a link between theoretical research and real-world implementations. In addition to exposing the most important attacks and issues we present fairly detailed pseudo-code for the authenticated DiffieHellman protocol and for the half-certified Diffie-Hellman (a.k.a. Elgamal key agreement). It is hoped that computer security practitioners will obtain enough information to build and design secure and efficient versions of this classic key agreement protocol.