@misc{cryptoeprint:2006:069,
author = {Bruno Blanchet and David Pointcheval},
title = {Automated Security Proofs with Sequences of Games},
howpublished = {Cryptology ePrint Archive, Report 2006/069},
year = {2006},
note = {\url{http://eprint.iacr.org/}},
}
You will need the url.sty package (comes with most LaTeX installations) for the last line. Otherwise, remove the \url command.