@misc{cryptoeprint:2004:181,
author = {Yehuda Lindell and Anna Lysyanskaya and Tal Rabin},
title = {On the Composition of Authenticated Byzantine Agreement},
howpublished = {Cryptology ePrint Archive, Report 2004/181},
year = {2004},
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.