Cryptology ePrint Archive: BibTeX Citation of Report 2013/308

@misc{cryptoeprint:2013:308,
    author = {Fabien Laguillaumie and Adeline Langlois and Benoit Libert and Damien Stehle},
    title = {Lattice-Based Group Signatures with Logarithmic Signature Size},
    howpublished = {Cryptology ePrint Archive, Report 2013/308},
    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.