@misc{cryptoeprint:2010:431,
author = {Jing Liu and Bo Yang},
title = {Collusion-Resistant Multicast Key Distribution Based on Homomorphic One-Way Function Trees},
howpublished = {Cryptology ePrint Archive, Report 2010/431},
year = {2010},
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.