Cryptology ePrint Archive: BibTeX Citation of Report 2008/248

@misc{cryptoeprint:2008:248,
    author = {Fengjiao Wang and Yuqing Zhang},
    title = {Cryptanalysis of a client-to-client password-authenticated key agreement protocol},
    howpublished = {Cryptology ePrint Archive, Report 2008/248},
    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.