@misc{cryptoeprint:2006:252,
author = {Maurizio A. Strangio},
title = {On the Resilience of Key Agreement Protocols to Key Compromise Impersonation},
howpublished = {Cryptology ePrint Archive, Report 2006/252},
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.