@misc{cryptoeprint:2011:313,
author = {Arpita Patra},
title = {Error-free Multi-valued Broadcast and Byzantine Agreement with Optimal Communication Complexity },
howpublished = {Cryptology ePrint Archive, Report 2011/313},
year = {2011},
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.