@misc{cryptoeprint:2003:069,
author = {M. Bellare and P. Rogaway and D. Wagner},
title = {EAX: A Conventional Authenticated-Encryption Mode},
howpublished = {Cryptology ePrint Archive, Report 2003/069},
year = {2003},
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.