Cryptology ePrint Archive: BibTeX Citation of Report 2012/711

@misc{cryptoeprint:2012:711,
    author = {Kai-Min Chung and Edward Lui and Mohammad Mahmoody and Rafael Pass},
    title = {Unprovable Security of Two-Message Zero Knowledge},
    howpublished = {Cryptology ePrint Archive, Report 2012/711},
    year = {2012},
    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.