@misc{cryptoeprint:2001:023,
author = {Martin Hirt and Ueli Maurer},
title = {Robustness for Free in Unconditional Multi-Party Computation},
howpublished = {Cryptology ePrint Archive, Report 2001/023},
year = {2001},
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.