@misc{cryptoeprint:2005:442,
author = {Dalit Naor and Amir Shenhav and Avishai Wool},
title = {One-Time Signatures Revisited: Have They Become Practical?},
howpublished = {Cryptology ePrint Archive, Report 2005/442},
year = {2005},
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.