@misc{cryptoeprint:2012:159,
author = {G.M. Zaverucha},
title = {Hybrid Encryption in the Multi-User Setting},
howpublished = {Cryptology ePrint Archive, Report 2012/159},
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.