@misc{cryptoeprint:2014:619,
author = {Mohammad Sadegh Nemati Nia, Ali Payandeh},
title = {THE NEW HEURISTIC GUESS AND DETERMINE ATTACK ON SNOW 2.0 STREAM CIPHER},
howpublished = {Cryptology ePrint Archive, Report 2014/619},
year = {2014},
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.