Cryptology ePrint Archive: BibTeX Citation of Report 2004/267

@misc{cryptoeprint:2004:267,
    author = {Patrick P. Tsang and Victor K. Wei and Tony K. Chan and Man Ho Au and Joseph K. Liu and Duncan S. Wong},
    title = {Separable Linkable Threshold Ring Signatures},
    howpublished = {Cryptology ePrint Archive, Report 2004/267},
    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.