@misc{cryptoeprint:2009:300, author = {M. Choudary Gorantla and Colin Boyd and Juan Manuel Gonz\`alez Nieto}, title = {Universally Composable Contributory Group Key Exchange}, howpublished = {Cryptology ePrint Archive, Report 2009/300}, year = {2009}, url = {http://eprint.iacr.org/2009/300}, }