I wrote up a short "test bed" for Dining Cryptographers over IRC (Internet Relay Chat). The implementation is not secure, as it uses PRIVMSGs to exchange flips between neighbors, but some good soul with a bit of time could go in and add DES encryption to them. The client allows for anonymous roundtable discussion between clients on a single IRC channel. The key-sharing graph is a ring, so it only takes two to collude to find what a particular person is sending, but that can be expanded also. There is no collision detection, but it is usually pretty obvious (i.e. if you send something and don't get it back, you know a collision happened). I also included a paper which has some discussion and references to making the DC implementation better, including things like protection against attacks coming from the IRC server itself, protection against someone sending stuff all the time disallowing service, etc. This has all been put in the cypherpunks ftp incoming directory. -Thomas