Cryptology ePrint Archive: BibTeX Citation of Report 2002/118

@misc{cryptoeprint:2002:118,
    author = {Alexandra Boldyreva},
    title = {Efficient threshold signature, multisignature and blind signature schemes based on the Gap-Diffie-Hellman-group signature scheme},
    howpublished = {Cryptology ePrint Archive, Report 2002/118},
    year = {2002},
    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.