@misc{cryptoeprint:1998:010,
author = {Hugo Krawczyk and Tal Rabin },
title = {Chameleon Hashing and Signatures},
howpublished = {Cryptology ePrint Archive, Report 1998/010},
year = {1998},
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.