@misc{cryptoeprint:2008:544,
author = {*Yalin Chen 1, Chun-Hui Huang 2, Jue-Sam Chou3 },
title = {Comments on two multi-server authentication protocols},
howpublished = {Cryptology ePrint Archive, Report 2008/544},
year = {2008},
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.