@misc{cryptoeprint:2013:584,
author = {Zongyue Wang, Hongbo Yu, Xiaoyun Wang},
title = {Cryptanalysis of GOST R Hash Function},
howpublished = {Cryptology ePrint Archive, Report 2013/584},
year = {2013},
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.