@misc{cryptoeprint:2015:873,
author = {Jian Liu, Sihem Mesnager, and Lusheng Chen},
title = {On the Diffusion Property of Iterated Functions},
howpublished = {Cryptology ePrint Archive, Report 2015/873},
year = {2015},
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.