An efficient key management for large dynamic groups

Key management for large dynamic groups is a difficult problem because of scalability and security. The SKDC (simple key distribution center) method is very weak in scalability. The logical key hierarchy (LKH) algorithm proposed in 1997 has greatly improved scalability for key management in large dynamic groups. In 1998, the one-way-function tree (OFT) method appeared to obtain more efficiency than LKH. But the OFT method has security breaches in collusion attacks. We present a new method which is more efficient than OFT and resistant to collusion attacks.