Multi-Device Encoded Video Signing with Difference Data
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Solution Overview
Problem
Existing methods for signing encoded video streams fail to maintain authenticity and integrity when legitimate alterations, such as transcoding, are made, as the signature no longer matches the altered stream.
Innovation Solution
A method involving a first device encoding and signing an image frame, and a second device applying video processing while incorporating difference data to maintain signature association, allowing validation of the original content even after alterations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a digital signature is embedded into the video stream to ensure authenticity and integrity, then the video stream can be verified for authenticity, but legitimate alterations such as transcoding cause the signature to no longer match the altered video stream
Solution Approach 1:
The patent segments the video stream into individual encoded image frames and applies signature association at the frame level rather than to the entire stream. This allows selective processing where some frames can be altered while maintaining signature validation for unaltered frames, resolving the contradiction between authenticity verification and processing flexibility
Solution Approach 2:
The patent performs preliminary decoding of the encoded image frame before signature determination, allowing the signature to be based on the decoded content rather than the encoded representation. This preliminary action enables subsequent re-encoding and processing while maintaining the ability to verify the original content's authenticity
2Productivity
If the signature is based on the encoded image frame data, then the signature can be determined efficiently, but video processing operations alter the encoded data causing signature mismatch
Solution Approach 1:
The patent introduces the decoded image frame as an intermediary representation between the encoded image frame and the signature. The signature is determined based on this intermediary decoded form, which remains stable despite subsequent re-encoding operations, thus maintaining both efficiency and validation accuracy
Solution Approach 2:
The patent creates a copy of the image content in decoded form as the basis for signature generation. This copied representation in a different format (decoded vs encoded) serves as a stable reference that is not affected by encoding variations, ensuring consistent signature validation
Data Source
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AI summary
The present disclosure relates to signing of an encoded video stream using a first device (102) and second device (120), wherein the first device (102) provides the original signatures (SA) of a first encoded video stream (110), wherein the second device (120) applies video processing (126) to the first encoded video stream (110) to modify the image frames thereof and include the modified image frames into a second encoded video stream (140). The second device (120) determines difference data (R) corresponding to the video processing (126) and includes the difference data in the second encoded video stream (140). On a decoder side, the decoder can authenticate the received second encoded video stream (140) by validating the original signatures (SA) using the difference data (R).