@misc{cryptoeprint:2005:387,
author = {C. Carlet},
title = {On highly nonlinear S-boxes and their inability to thwart DPA attacks (completed version)},
howpublished = {Cryptology ePrint Archive, Report 2005/387},
year = {2005},
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.