@misc{cryptoeprint:2014:645,
author = {Craig Gentry and Sergey Gorbunov and Shai Halevi},
title = {Graph-Induced Multilinear Maps from Lattices},
howpublished = {Cryptology ePrint Archive, Report 2014/645},
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.