Cryptology ePrint Archive: BibTeX Citation of Report 2004/321

@misc{cryptoeprint:2004:321,
    author = {Vladimir Shpilrain and Alexander Ushakov},
    title = {The conjugacy search problem in public key cryptography: unnecessary and insufficient},
    howpublished = {Cryptology ePrint Archive, Report 2004/321},
    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.