Cryptology ePrint Archive: BibTeX Citation of Report 2003/153

@misc{cryptoeprint:2003:153,
    author = {Zhen-Feng ZHANG and Jing XU and Deng-Guo FENG},
    title = {Attack on an Identification Scheme Based on Gap Diffie-Hellman Problem},
    howpublished = {Cryptology ePrint Archive, Report 2003/153},
    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.