Cryptology ePrint Archive: BibTeX Citation of Report 2009/394

@misc{cryptoeprint:2009:394,
    author = {Le Trieu Phong and Kaoru Kurosawa and Wakaha Ogata},
    title = {Provably Secure Convertible Undeniable Signatures with Unambiguity},
    howpublished = {Cryptology ePrint Archive, Report 2009/394},
    year = {2009},
    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.