Cryptology ePrint Archive: BibTeX Citation of Report 2005/203

@misc{cryptoeprint:2005:203,
    author = {Nicolas Courtois and Blandine Debraize and Eric Garrido},
    title = {On Exact Algebraic [Non-]Immunity of S-boxes Based on Power Functions},
    howpublished = {Cryptology ePrint Archive, Report 2005/203},
    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.