@misc{cryptoeprint:2009:026,
author = {Zhimin Li, Licheng Wang, Daofeng Li, Yixian Yang},
title = {Collision Attacks on NaSHA-384/512},
howpublished = {Cryptology ePrint Archive, Report 2009/026},
year = {2009},
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.