Cryptology ePrint Archive: BibTeX Citation of Report 2004/214

@misc{cryptoeprint:2004:214,
    author = {An Braeken, Christopher Wolf, and Bart Preneel},
    title = {Classification of Highly Nonlinear Boolean Power Functions with a Randomised Algorithm for Checking Normality},
    howpublished = {Cryptology ePrint Archive, Report 2004/214},
    year = {2004},
    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.