Cryptology ePrint Archive: BibTeX Citation of Report 2007/320

@misc{cryptoeprint:2007:320,
    author = {Zhengjun Cao},
    title = {On the Big Gap   Between $|p|$ and $|q|$ in DSA},
    howpublished = {Cryptology ePrint Archive, Report 2007/320},
    year = {2007},
    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.