Cryptology ePrint Archive: BibTeX Citation of Report 2004/222

@misc{cryptoeprint:2004:222,
    author = {An Braeken and Christopher Wolf and Bart Preneel},
    title = {A Study of the Security of Unbalanced Oil and Vinegar Signature Schemes},
    howpublished = {Cryptology ePrint Archive, Report 2004/222},
    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.