Cryptology ePrint Archive: BibTeX Citation of Report 2015/164

@misc{cryptoeprint:2015:164,
    author = {Priyanka Bose and Dipanjan Das and C. Pandu Rangan},
    title = {Constant Size Ring Signature Without Random Oracle},
    howpublished = {Cryptology ePrint Archive, Report 2015/164},
    year = {2015},
    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.