Cryptology ePrint Archive: BibTeX Citation of Report 2007/280

@misc{cryptoeprint:2007:280,
    author = {Igor Semaev},
    title = {On solving sparse algebraic equations over finite fields II},
    howpublished = {Cryptology ePrint Archive, Report 2007/280},
    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.