@misc{cryptoeprint:2002:100,
author = {J. Black and P. Rogaway and T. Shrimpton},
title = {Encryption-Scheme Security in the Presence of Key-Dependent Messages},
howpublished = {Cryptology ePrint Archive, Report 2002/100},
year = {2002},
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.