Cryptology ePrint Archive: BibTeX Citation of Report 2013/400

@misc{cryptoeprint:2013:400,
    author = {Razvan Barbulescu and Pierrick Gaudry and Antoine Joux and Emmanuel Thomé},
    title = {A quasi-polynomial algorithm for discrete logarithm in finite fields of small characteristic},
    howpublished = {Cryptology ePrint Archive, Report 2013/400},
    year = {2013},
    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.