@misc{cryptoeprint:2004:017,
author = {M. Scott},
title = {Cryptanalysis of an ID-based Password Authentication Scheme using Smart Cards and Fingerprints},
howpublished = {Cryptology ePrint Archive, Report 2004/017},
year = {2004},
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.