@misc{cryptoeprint:2008:059,
author = {Stefan Popoveniuc and Jonathan Stanton},
title = {Buying random votes is as hard as buying no-votes},
howpublished = {Cryptology ePrint Archive, Report 2008/059},
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.