@misc{cryptoeprint:2009:224,
author = {Keting Jia and Yvo Desmedt and Lidong Han and Xiaoyun Wang },
title = {Pseudo-Cryptanalysis of Luffa},
howpublished = {Cryptology ePrint Archive, Report 2009/224},
year = {2009},
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.