@misc{cryptoeprint:2010:323,
author = {Charles Bouillaguet and Pierre-Alain Fouque and Gaëtan Leurent},
title = {Security Analysis of SIMD},
howpublished = {Cryptology ePrint Archive, Report 2010/323},
year = {2010},
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.