Progressive and scalable encryption for multimedia content access control

Encryption is one of the most important security tools for secure message communication. There is an increasing need for secure digital multimedia communication technologies to restrict unauthorized access. Prior to the availability of variable bit rate (VBR) communication services, systems typically treat every portion of a message equally and encrypt each and every bit of a message that is decrypted at the same rate as encrypted. Hence, encryption/decryption processes at both ends of the network were required to operate at the same rate. The advent of VBR multimedia communication services require new cryptography system implementations that can operate at different data rates, i.e., be scaled to different speed, different network bandwidths, and diverse receiver device capabilities. In this paper, we describe a progressive and scalable encryption scheme that supports scalability. One desirable feature of the proposed scheme is its simplicity and flexibility in supporting scalable multimedia communication and multimedia content access control.