@misc{cryptoeprint:2001:107,
author = {Yehuda Lindell},
title = {Parallel Coin-Tossing and Constant-Round Secure Two-Party Computation},
howpublished = {Cryptology ePrint Archive, Report 2001/107},
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.