IPTV Client Decryption Using Separate ECM Storage
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Solution Overview
Problem
In IPTV systems, delivering encrypted video content with entitlement control messages (ECMs) to network personal video recorders (nPVRs) is challenging due to performance issues with data manipulation in recording equipment and limited bandwidth, which prevents simultaneous delivery of two audio/video streams.
Innovation Solution
A method of decrypting scrambled digital data items at a client by receiving actual control messages separately from the scrambled data, allowing for independent storage and decryption of the data without requiring ECMs to be stored with the video content, and using multicast or unicast protocols to manage bandwidth effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ECMs are stored with video content in network recording equipment, then decryption functionality is enabled, but equipment performance deteriorates due to excessive data manipulation
Solution Approach 1:
The patent extracts ECMs from the video transport stream and stores them separately in a database, eliminating the need for recording equipment to manipulate ECMs during playback. This separation resolves the contradiction by enabling decryption functionality while preventing performance deterioration from excessive data manipulation.
Solution Approach 2:
The patent introduces a network server as an intermediary that stores ECMs in a database and delivers them to STBs on demand. This intermediary handles the complexity of ECM management, allowing recording equipment to focus solely on video storage and playback, thus maintaining high performance while enabling decryption.
2Reliability
If ECMs are delivered with video content, then decryption is enabled, but bandwidth consumption increases preventing simultaneous delivery of two A/V streams
Solution Approach 1:
The patent delivers ECMs to STBs in advance before the associated video content. STBs store these ECMs locally and use them when needed, eliminating the need to transmit ECMs simultaneously with video streams. This preliminary delivery enables decryption capability while reducing bandwidth consumption to allow simultaneous delivery of multiple A/V streams.
3Reliability
If ECMs are stored in network recording equipment, then decryption functionality is provided, but device complexity increases
Solution Approach 1:
The patent extracts ECM management functionality from recording equipment and relocates it to a separate network server with a database. This extraction reduces device complexity in recording equipment while maintaining decryption functionality through the centralized ECM storage and delivery system.
Solution Approach 2:
The patent creates a universal ECM delivery system that serves multiple STBs and multiple video streams through a centralized database. This multi-functional approach reduces individual device complexity by consolidating ECM management infrastructure that can handle various decryption requirements across the network.
Data Source
AI summary
A method of decrypting a scrambled digital data item at a client is disclosed, the method including: receiving actual control messages at the client, wherein each actual control message includes control word generating information for generating a control word associated with the actual control message; storing the actual control messages at the client; receiving the scrambled digital data item at the client independently of the actual control messages, wherein the scrambled digital data item includes a plurality of segments of scrambled digital data, each segment of scrambled digital data being associated with one of the actual control messages and being scrambled with the control word associated with the one of the actual control messages, and wherein the scrambled digital data item further includes a plurality of reference control messages, each segment of scrambled digital data comprising one of the reference control messages, each of the reference control messages including a control message reference value identifying the actual control message associated with the segment of scrambled digital data; and decrypting the scrambled digital data item using the plurality of actual control messages.