@misc{cryptoeprint:2007:118,
author = {Shai Halevi and Yael Tauman Kalai},
title = {Smooth Projective Hashing and Two-Message Oblivious Transfer},
howpublished = {Cryptology ePrint Archive, Report 2007/118},
year = {2007},
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.