@misc{cryptoeprint:2009:337,
author = {Yanbin Pan and Yingpu Deng and Yupeng Jiang and Ziran Tu},
title = {A New Lattice-Based Cryptosystem Mixed with a Knapsack},
howpublished = {Cryptology ePrint Archive, Report 2009/337},
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.