Cryptology ePrint Archive: BibTeX Citation of Report 2006/443

@misc{cryptoeprint:2006:443,
    author = {Yvo Desmedt and Tanja Lange and Mike Burmester},
    title = {Scalable Authenticated Tree Based Group Key Exchange for Ad-Hoc Groups},
    howpublished = {Cryptology ePrint Archive, Report 2006/443},
    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.