@misc{cryptoeprint:2004:038,
author = {Xiaofeng Chen and Fangguo Zhang and Kwangjo Kim },
title = {Chameleon Hashing without Key Exposure},
howpublished = {Cryptology ePrint Archive, Report 2004/038},
year = {2004},
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.