Cryptology ePrint Archive: BibTeX Citation of Report 2004/153

@misc{cryptoeprint:2004:153,
    author = {P. Gaudry and E. Thom{\'e} and N. Th{\'e}riault and C. Diem},
    title = {A double large prime variation for small genus hyperelliptic index calculus},
    howpublished = {Cryptology ePrint Archive, Report 2004/153},
    year = {2004},
    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.