@misc{cryptoeprint:2012:180,
author = {Brian Baldwin and William P. Marnane},
title = {Yet Another SHA-3 Round 3 FPGA Results Paper},
howpublished = {Cryptology ePrint Archive, Report 2012/180},
year = {2012},
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.