@misc{cryptoeprint:2008:441,
author = {Gaetan Leurent and Phong Q. Nguyen},
title = {How Risky is the Random-Oracle Model?},
howpublished = {Cryptology ePrint Archive, Report 2008/441},
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.