Circumference is a server-client-style implementation of a WebAuth client and server to supplement the WebAuth Diameter subprotocol, complete with an extensible Diameter server and base library. Diameter is a peer-to-peer authentication protocol as specified in RFC3588 and its updates.
You can download it from the following link: https://packetstormsecurity.com/files/download/107511/circumference-1.5.tar.bz2
Source: https://packetstormsecurity.com/files/107511/Circumference-WebAuth-Client-1.5.html