Key Bundles and Parcels: Secure Communication in Many Groups
We consider a system where each user is in one or more elementary groups. In this system, arbitrary groups of users can be specified using the operations of union, intersection, and complement over the elementary groups in the system. Each elementary group in the system is provided with a security key that is known only to the users in the elementary group and to the system server. Thus, for any user u to securely multicast a data item d to every user in an arbitrary group G, u first forwards d to the system server which encrypts it using the keys of the elementary groups that comprise G before multicasting the encrypted d to every user in G. Every elementary group is also provided with a key tree to ensure that the cost of changing the key of the elementary group, when a user leaves the group, is small. We describe two methods for packing the key trees of elementary groups into key bundles and into key parcels. Packing into key bundles has the advantage of reducing the number of encryptions needed to multicast a data item to the complement of an elementary group. Packing into key parcels has the advantage of reducing the total number of keys in the system. We apply these two methods to a class of synthetic systems: each system has 10000 users and 500 elementary groups, and each user is in 2 elementary groups on average. Simulations of these systems show that our proposals to pack key trees into key bundles and key parcels live up to their promises.
KeywordsData Item Elementary Group Arbitrary Group Secure Group Communication 10th International World Wide
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- 2.Mittra, S.: Iolus: a framework for scalable secure multicasting. In: The Proceedings of the ACM SIGCOMM 1997, pp. 277–288. ACM Press, New York (1997)Google Scholar
- 3.Wallner, D.M., Harder, E.J., Agee, R.C.: Key management for multicast: Issues and architectures. RFC 2627 (1999) Google Scholar
- 6.Gong, L., Shacham, N.: Multicast security and its extension to a mobile environment. Wireless Networks 1, 281–295 (1995) Google Scholar
- 7.Ballardie, A.: Scalable multicast key distribution. RFC 1949 (1996) Google Scholar
- 8.Chang, I., Engel, R., Kandlur, D.D., Pendarakis, D.E., Saha, D.: Key management for secure internet multicast using boolean function minimization techniques. In: The Proceedings of IEEE Infocom 1999, vol. 2, pp. 689–698 (1999)Google Scholar
- 11.Setia, S., Koussih, S., Jajodia, S., Harder, E.: Kronos: A scalable group re-keying approach for secure multicast. In: The Proceedings of IEEE Symposium on Security and Privacy (2000) Google Scholar
- 13.Gouda, M.G., Huang, C.T., Elnozahy, E.: Key trees and the security of the interval multicast. In: The Proceedings of the 22nd International Conference on Distributed Computing Systems, pp. 467–468 (2002) Google Scholar
- 16.Snoeyink, J., Suri, S., Varghese, G.: A lower bound for multicast key distribution. In: The Proceedings of IEEE Infocom 2001, pp. 667–675 (2001) Google Scholar
- 17.Jung, E., Liu, X.Y.A., Gouda, M.G.: Key bundles and parcels: Secure communication in many groups. Technical Report TR-03-21, Dept. of Computer Sciences, The University of Texas at Austin (2003)Google Scholar