@misc{cryptoeprint:2011:407,
author = {Elaine Shi, Hubert Chan, Emil Stefanov, Mingfei Li},
title = {Oblivious RAM with O((log N)^3) Worst-Case Cost},
howpublished = {Cryptology ePrint Archive, Report 2011/407},
year = {2011},
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.