A new scalable key-management scheme for secure multicast

Recently, Multicasting is increasingly used as an efficient communication mechanism in the internet. Secure group communication is vital for many group-based applications such as pay-per view. One solution is to let all members in the group share a group key that is used for encrypting the data. To ensure perfect backward and forward secrecy, this shared group key has to be updated with every membership change and redistributed to all authorized members securely. With the fact that the group can be large and highly dynamic, changing the group key on membership change in an efficient and scalable way becomes necessary. Designing a group key management scheme which can distribute and re-keying the group key efficiently in a large dynamic group is full of challenge. In the paper, a new key-management scheme based the logical-key tree is proposed to reduce the key storage requirement of a group controller and to optimize the key update overhead through introducing the pseudo-random function, XOR operation and one-way function. Compared with those previously proposed, the new proposed approach has obvious superiority in storage and communication overhead.