Cryptology ePrint Archive: BibTeX Citation of Report 2009/636

@misc{cryptoeprint:2009:636,
    author = {Haining Fan and Ming Gu and Jiaguang Sun and Kwok-Yan Lam},
    title = {Obtaining More Karatsuba-Like Formulae over The Binary Field},
    howpublished = {Cryptology ePrint Archive, Report 2009/636},
    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.