@misc{cryptoeprint:2014:885,
author = {Marios O. Choudary and Markus G. Kuhn},
title = {Efficient Stochastic Methods: Profiled Attacks Beyond 8 Bits},
howpublished = {Cryptology ePrint Archive, Report 2014/885},
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.