Cryptology ePrint Archive: BibTeX Citation of Report 2006/181

@misc{cryptoeprint:2006:181,
    author = {Sel\c{c}uk Kavut and Subhamoy Maitra and Melek D. Y{\"u}cel},
    title = {There exist Boolean functions on $n$ (odd) variables having nonlinearity $> 2^{n-1} - 2^{\frac{n-1}{2}}$ if and only if $n > 7$},
    howpublished = {Cryptology ePrint Archive, Report 2006/181},
    year = {2006},
    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.