@misc{cryptoeprint:2008:427,
author = {Jesper Buus Nielsen and Claudio Orlandi},
title = {LEGO for Two Party Secure Computation},
howpublished = {Cryptology ePrint Archive, Report 2008/427},
year = {2008},
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.