@misc{cryptoeprint:2014:672,
author = {Xiao Wang and Hubert Chan and Elaine Shi},
title = {Circuit ORAM: On Tightness of the Goldreich-Ostrovsky Lower Bound},
howpublished = {Cryptology ePrint Archive, Report 2014/672},
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.