@misc{cryptoeprint:2007:287,
author = {Kevin Henry and Douglas R. Stinson and Jiayuan Sui},
title = {The Effectiveness of Receipt-Based Attacks on ThreeBallot},
howpublished = {Cryptology ePrint Archive, Report 2007/287},
year = {2007},
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.