Conditional Access Control Message Segmentation
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Solution Overview
Problem
Existing pay-TV systems face complexity in managing various access conditions, require high bandwidth for entitlement management messages, and experience long waiting times when changing channels due to the need for multiple control word transmissions.
Innovation Solution
A method where a user unit receives a unique key from the management center to access a package of services, with control words for each service encrypted using this key, allowing simultaneous decryption of multiple services and reducing bandwidth usage by transmitting control messages directly to the user unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If entitlement management messages are broadcast in encrypted form with multiple control words for different services, then security level is maintained, but bandwidth consumption increases significantly
Solution Approach 1:
The patent segments the entitlement management process by separating control words for different services into distinct messages. Each control word is encrypted with a service-specific key and transmitted independently, allowing selective delivery only to users entitled to each service. This segmentation enables bandwidth optimization by transmitting only necessary control words to appropriate users rather than broadcasting all service control words to everyone.
Solution Approach 2:
The patent applies local quality by encrypting control words with service-specific keys tailored to each user's entitlements. Each user receives customized control words encrypted with keys relevant to their subscription level, rather than a uniform encrypted broadcast for all services. This localized approach ensures security is maintained for each user-service combination while reducing overall bandwidth by excluding irrelevant control words from user transmissions.
2Reliability
If multiple control words are transmitted separately for different services, then access control is maintained, but channel change waiting time increases
Solution Approach 1:
The patent implements preliminary action by pre-transmitting and storing control words for multiple services in the user unit's memory before channel changes occur. When a user changes channels, the required control words are already available in memory rather than needing to be transmitted in real-time. This preliminary preparation eliminates transmission delays during channel changes while maintaining access control through encrypted service-specific keys.
Solution Approach 2:
The patent ensures continuity of useful action by maintaining control words in memory for rapid retrieval during channel changes. The system continuously manages and stores control words for all subscribed services, ensuring that when a channel change occurs, the necessary control words are immediately available without interruption to the viewing experience. This continuous availability maintains access control while eliminating waiting time during channel transitions.
3Reliability
If a conditional access kernel is implemented to manage various access conditions, then security is maintained, but system complexity increases
Solution Approach 1:
The patent extracts the complex conditional access kernel functionality and implements it through simpler service-specific encryption keys and entitlement-based control word distribution. Instead of a centralized complex kernel managing all access conditions, the system uses individual service keys and user entitlements to determine which control words each user receives. This extraction simplifies the overall system architecture while maintaining security through distributed key management.
Solution Approach 2:
The patent applies universality by creating a multi-functional control word transmission system that handles multiple services and user entitlements through a unified encrypted message framework. The same basic transmission mechanism serves different purposes for different services and user levels, eliminating the need for separate specialized systems for each access condition. This universal approach reduces system complexity while maintaining comprehensive security across all services.
Data Source
AI summary
The invention concerns a method for providing a plurality of receivers with conditional access to broadcast services using a simplified means for managing the control messages required by such conditional access schemes. The method involves providing all information which will allow a registered receiver having the necessary decryption key to access the services without having any prior rights loaded locally. A management center keeps a register of all subscribed receivers, including a list of services to which the receiver is subscribed, and encrypts the services using control words encrypted by the necessary keys. Control messages comprising the control words for decryption are provided within a special channel to which the receiver has permanent access, the special channel being a different one from channels used for broadcasting audio/video services.