@misc{cryptoeprint:2008:466,
author = {Maria Isabel Gonzalez Vasco and Florian Hess and Rainer Steinwandt},
title = {Combined (identity-based) public key schemes},
howpublished = {Cryptology ePrint Archive, Report 2008/466},
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.