Video Stream Trustworthiness Checks Using Hashes and Digital Signatures
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Solution Overview
Problem
Existing video coding standards lack methods for standard compliant decoders to verify if a compressed bitstream was generated by a trustworthy source, particularly in the context of potential deep-fake content, posing risks to copyright and personal rights, and undermining trust in public institutions.
Innovation Solution
A method is introduced to render video data streams checkable on trustworthiness by hashing a predetermined portion, computing a digital signature, and transmitting it within the stream, allowing decoders to verify authenticity by comparing hash values with the signature, while maintaining flexibility and reducing signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a digital signature is computed for the entire video data stream, then the trustworthiness verification becomes comprehensive, but the signaling overhead increases significantly
Solution Approach 1:
The video data stream is divided into predetermined portions (e.g., individual pictures or groups of pictures), and separate digital signatures are computed for each portion. This segmentation allows the system to verify trustworthiness at a granular level while keeping each signature manageable in size, thus reducing the overall signaling overhead compared to signing the entire stream.
Solution Approach 2:
The patent extracts only the essential verification elements (digital signatures of predetermined portions) from the complete video data stream. By transmitting only these extracted signature portions rather than the entire stream, the system achieves effective trustworthiness verification while minimizing the additional data burden.
2Reliability
If the predetermined portion includes the entire video data stream, then the verification covers all content, but the processing time and computational effort increase
Solution Approach 1:
The video data stream is segmented into predetermined portions (such as individual pictures or groups of pictures), allowing parallel or sequential processing of smaller units. This segmentation reduces the time required to compute and verify digital signatures compared to processing the entire stream as a single unit, while still providing comprehensive verification coverage.
Solution Approach 2:
Digital signatures for predetermined portions are computed in advance during the encoding phase and embedded into the video data stream. This preliminary action allows the decoder to verify trustworthiness quickly during playback without performing time-consuming signature computations in real-time, thus reducing processing time during critical verification moments.
3Measurement precision
If the digital signature is transmitted in full detail, then the verification accuracy is maximized, but the data transmission bandwidth is consumed
Solution Approach 1:
The patent extracts and transmits only the necessary digital signature portions corresponding to predetermined segments of the video data stream. By transmitting these extracted signature elements rather than redundant or excessive verification data, the system maintains verification accuracy while minimizing the additional data transmission volume.
Solution Approach 2:
The verification data is segmented into discrete digital signatures for specific predetermined portions of the video stream. This segmentation allows the system to transmit only the relevant verification information needed for each segment, avoiding the transmission of unnecessary data while maintaining sufficient verification accuracy for each portion.
Data Source
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AI summary
A method for checking a video data stream having a video encoded thereinto on trustworthiness comprises: subjecting a predetermined portion of the video data stream, or data derived therefrom, to a hash function to obtain a hash value; deriving a digital signature from the video data stream; and checking whether the hash value fits to the digital signature to determine whether the video data stream is trustworthy.