Conditional Access Subsystem Hook Piracy Prevention
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Solution Overview
Problem
Existing conditional access systems in receiver systems are vulnerable to hook piracy, where a single smart card is used to descramble multiple program transport streams, allowing unauthorized sharing of subscriptions.
Innovation Solution
Implementing a method in the conditional access sub-system to analyze sequences of messages for concurrent descrambling requests, limiting the number of program transport streams that can be descrambled based on predetermined criteria, such as time intervals and channel identifiers, to prevent unauthorized access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the security processor returns control words in response to each ECM for which an appropriate EMM has been sent, then the system allows flexible access to multiple program transport streams, but this opens up the opportunity of hook piracy where a single smart card can be used to descramble multiple streams concurrently
Solution Approach 1:
The system performs preliminary analysis of incoming ECM sequences to detect potential hook piracy attempts before granting access. By examining the temporal patterns and characteristics of received ECMs in advance, the conditional access subsystem can identify suspicious activity patterns and prevent unauthorized concurrent access before it occurs.
Solution Approach 2:
The system implements feedback mechanisms that monitor the behavior of smart cards and receivers in real-time. By analyzing the sequences of ECMs received and the corresponding control word requests, the system can detect abnormal patterns indicative of hook piracy and dynamically adjust access decisions, providing feedback control over the descrambling process.
2Ease of operation
If the system allows concurrent descrambling of multiple program transport streams, then user convenience is improved, but unauthorized sharing of subscriptions becomes possible
Solution Approach 1:
The system performs preliminary validation and analysis of access requests before allowing concurrent descrambling. By examining the temporal patterns, channel identifiers, and message sequences in advance, the system can determine whether multiple concurrent access requests are legitimate or represent unauthorized sharing attempts, making security decisions before granting access.
Solution Approach 2:
The system dynamically changes security parameters such as the number of allowed concurrent streams, time intervals between ECMs, and validation criteria based on the detected behavior patterns. By adjusting these parameters in real-time, the system can accommodate legitimate multi-stream access while preventing unauthorized sharing.
Data Source
AI summary
A method of controlling descrambling of a plurality of program transport streams received by a receiver system comprises receiving a sequence of messages in a conditional access sub-system (9,10) comprised in said receiver system, each message being associated with one of a number of scrambled program transport streams and representing a request for returning information enabling the associated scrambled transport stream to be descrambled by at least one descrambler module (12) in the receiver system, determining whether messages received within a certain interval are associated with a number of different scrambled program transport streams, and denying at least one of the requests represented by the messages received in the certain interval, if the number of different scrambled program transport streams with which the messages are associated exceeds a pre-determined number.