Cryptology ePrint Archive: BibTeX Citation of Report 2001/111

@misc{cryptoeprint:2001:111,
    author = {N.P. Smart},
    title = {An Identity Based Authenticated Key Agreement Protocol  Based on the Weil Pairing},
    howpublished = {Cryptology ePrint Archive, Report 2001/111},
    year = {2001},
    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.