Cryptology ePrint Archive: BibTeX Citation of Report 2004/164

@misc{cryptoeprint:2004:164,
    author = {Man Ho Au and Victor K. Wei},
    title = {ID-based Cryptography from Composite Degree Residuosity},
    howpublished = {Cryptology ePrint Archive, Report 2004/164},
    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.