Cryptology ePrint Archive: BibTeX Citation of Report 2003/104

@misc{cryptoeprint:2003:104,
    author = {Fangguo Zhang and Reihaneh Safavi-Naini and Chih-Yin Lin },
    title = {New Proxy Signature, Proxy Blind Signature and Proxy Ring Signature Schemes from Bilinear Pairing},
    howpublished = {Cryptology ePrint Archive, Report 2003/104},
    year = {2003},
    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.