Cryptology ePrint Archive: BibTeX Citation of Report 2004/293

@misc{cryptoeprint:2004:293,
    author = {Jana Dittmann and Stefan Katzenbeisser and Christian Schallhart and Helmut Veith},
    title = {Provably Secure Authentication of Digital Media Through Invertible Watermarks},
    howpublished = {Cryptology ePrint Archive, Report 2004/293},
    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.