Cryptology ePrint Archive: BibTeX Citation of Report 2006/056

@misc{cryptoeprint:2006:056,
    author = {Anupam Datta and Ante Derek and John C. Mitchell and Bogdan Warinschi},
    title = {Key Exchange Protocols: Security Definition, Proof Method and Applications},
    howpublished = {Cryptology ePrint Archive, Report 2006/056},
    year = {2006},
    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.