Cryptology ePrint Archive: BibTeX Citation of Report 2004/143

@misc{cryptoeprint:2004:143,
    author = {Nicolas T. Courtois},
    title = {Short Signatures, Provable Security, Generic Attacks and Computational Security of Multivariate Polynomial Schemes such as HFE, Quartz and Sflash },
    howpublished = {Cryptology ePrint Archive, Report 2004/143},
    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.