@misc{cryptoeprint:2003:234,
author = {Gene Itkis and Peng Xie},
title = {Generalized Key-Evolving Signature Schemes or How to Foil an Armed Adversary},
howpublished = {Cryptology ePrint Archive, Report 2003/234},
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.