Cryptology ePrint Archive: BibTeX Citation of Report 2012/199

@misc{cryptoeprint:2012:199,
    author = {Jean-Charles Faugère and Pierrick Gaudry and Louise Huot and Guénaël Renault},
    title = {Using Symmetries in the Index Calculus for Elliptic Curves Discrete Logarithm},
    howpublished = {Cryptology ePrint Archive, Report 2012/199},
    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.