Control Word Server Workload Smoothing via Preliminary Decryption
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Solution Overview
Problem
The existing systems for secure multimedia content distribution face high workload peaks on control word servers when multiple users simultaneously change channels, leading to increased computational demands and potential bottlenecks.
Innovation Solution
Implementing a method where terminals pre-receive and store control words for subsequent channels, allowing them to descramble content without immediate requests to the server during channel changes, thereby reducing the need for simultaneous decryption requests and smoothing the workload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control words are decrypted in real-time when users change channels, then content availability is ensured, but server workload peaks occur during simultaneous channel changes
Solution Approach 1:
The system performs preliminary decryption of control words before users actually need them. Terminals store decrypted control words in advance, so when channel changes occur simultaneously, the control words are already ready for immediate use, eliminating the need for real-time decryption during peak load periods
2Loss of time
If control words are transmitted immediately upon request, then response time is minimized, but network bandwidth is consumed during peak periods
Solution Approach 1:
Control words are transmitted and decrypted in advance before users change channels. Terminals receive and store the control words beforehand, so when channel changes occur, no additional network transmission is needed, eliminating bandwidth consumption during peak periods while maintaining immediate response capability
3Speed
If terminals store decrypted control words locally, then decryption speed is improved, but security risks increase
Solution Approach 1:
Terminals store decrypted control words in advance before they are needed. This preliminary storage allows immediate use without real-time decryption, improving speed while the security risk is managed by limiting the storage duration and amount of sensitive data at any given time
4Device complexity
If the control word server processes all decryption requests simultaneously, then system simplicity is maintained, but server load becomes unmanageable during peak periods
Solution Approach 1:
The system shifts the decryption operation from real-time during channel changes to advance before channel changes. Terminals perform decryption beforehand and store the results, so the server does not need to process decryption requests during peak simultaneous channel change periods, making server load manageable while maintaining system simplicity
Data Source
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AI summary
The invention relates to a method for decrypting control words for a first and second terminal, that includes: a control word server that transmits (162) to the first terminal a control word CW2,t obtained by decrypting a cryptogram CW*2,t transmitted by the second terminal even before the first terminal changes a descrambled channel by switching from the first to the second channel, wherein in response to the channel change, the first terminal first checks (126) if the control word CW2,t has already been preliminarily sent by the control word server even before the channel change and, in such a case, the first terminal immediately starts descrambling (130) the multimedia content broadcasted on the second channel using the control word CW2,t.