Cryptology ePrint Archive: BibTeX Citation of Report 2008/169

@misc{cryptoeprint:2008:169,
    author = {Côme Berbain and Aline Gouget and Hervé Sibert},
    title = {Understanding Phase Shifting Equivalent Keys and Exhaustive Search},
    howpublished = {Cryptology ePrint Archive, Report 2008/169},
    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.