@misc{cryptoeprint:2007:302,
author = {Hidenori Kuwakado and Masakatu Morii},
title = {Compression Functions Suitable for the Multi-Property-Preserving Transform},
howpublished = {Cryptology ePrint Archive, Report 2007/302},
year = {2007},
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.