Matrix-tree based hybrid broadcast encryption

Broadcast encryption in a pay television system is actually a key management issue, where smaller key storage and shorter header length are required to assure the quality of service. The existing solutions come up with two typical structures. One is the matrix-based structure without revocation capability and the other is the tree-based structure in Advanced Access Content System. In this paper, we propose two promising schemes that exploit the combination of the two structures to solve the revocation problem in the matrix-based structure to meet the requirements of the small key storage and short header. Mathematical derivations and calculations are performed to prove the feasibility of the proposed schemes.