@misc{cryptoeprint:2008:424,
author = {Arpita Patra, Ashish Choudhury and C. Pandu Rangan},
title = {Asynchronous Byzantine Agreement with Optimal Resilience},
howpublished = {Cryptology ePrint Archive, Report 2008/424},
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.