@misc{cryptoeprint:2013:380,
author = {Yalin Chen 1, *Jue-Sam Chou2, Wen-Yi Tsai 3},
title = {Comments on Three Multi-Server Authentication Protocols},
howpublished = {Cryptology ePrint Archive, Report 2013/380},
year = {2013},
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.