@misc{cryptoeprint:2008:313,
author = {Yves Edel and Alexander Pott},
title = {A new almost perfect nonlinear function which is not quadratic},
howpublished = {Cryptology ePrint Archive, Report 2008/313},
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.