Cryptology ePrint Archive: BibTeX Citation of Report 2010/335

@misc{cryptoeprint:2010:335,
    author = {Patrick Longa, and Catherine Gebotys},
    title = {Analysis of Efficient Techniques for Fast Elliptic Curve Cryptography  on x86-64 based Processors},
    howpublished = {Cryptology ePrint Archive, Report 2010/335},
    year = {2010},
    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.