Cryptology ePrint Archive: BibTeX Citation of Report 2003/262

@misc{cryptoeprint:2003:262,
    author = {Sherman S.M. Chow and Lucas C.K. Hui and S.M. Yiu and K.P. Chow},
    title = {A Secure Modified ID-Based Undeniable Signature Scheme},
    howpublished = {Cryptology ePrint Archive, Report 2003/262},
    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.