@misc{cryptoeprint:2009:519,
author = {Juan Garay and Clint Givens and Rafail Ostrovsky},
title = {Secure Message Transmission with Small Public Discussion},
howpublished = {Cryptology ePrint Archive, Report 2009/519},
year = {2009},
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.