@misc{cryptoeprint:2013:235,
author = {Ben Smyth and David Bernhard},
title = {Ballot secrecy and ballot independence: definitions and relations},
howpublished = {Cryptology ePrint Archive, Report 2013/235},
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.