Video Data Block Signature Generation for Integrity Certification
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Solution Overview
Problem
Conventional methods for ensuring the reliability and integrity of video evidence recorded by surveillance cameras, especially those operating continuously, fail to provide effective certification against falsification and data integrity when errors such as power outages occur, leading to incomplete or inaccurate certification of video data.
Innovation Solution
A system comprising a certificate authority device, a signature generating device, and a signature verifying device that divides video data into blocks, generates frame digests using cryptographic hash functions, and appends digital signatures to these blocks, ensuring the integrity and continuity of the video data even during unexpected interruptions, such as power outages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital signature is appended only when recording stops formally, then certification procedure is simple, but certification cannot be provided when errors occur during recording
Solution Approach 1:
The video data is divided into fixed-size blocks (e.g., 300 frames per block). Digital signatures are generated for each block independently as they are formed, rather than waiting for formal recording termination. This segmentation allows continuous certification without requiring complete recording completion, solving the reliability issue while maintaining manageable complexity through standardized block processing.
Solution Approach 2:
The system performs preliminary signature generation for complete blocks before final recording termination. When a block is fully formed (e.g., 300 frames accumulated), its signature is generated in advance, ensuring that even if recording stops unexpectedly, all complete blocks have valid certification. This preliminary action guarantees certification reliability without requiring complex post-processing.
2Reliability
If video data is certified in large units, then certification coverage is comprehensive, but inability to certify continuous recording is detected
Solution Approach 1:
Video data is segmented into fixed-size blocks (e.g., 300 frames each). Each block is independently hashed and signed, creating granular integrity checkpoints. This segmentation prevents information loss about continuous recording because each block's signature verifies that specific time period's data hasn't been tampered with or lost, providing fine-grained continuity detection.
Solution Approach 2:
The signature generation process operates continuously on incoming video data, processing each complete block as it forms without interruption. This continuous action ensures that every segment of recorded video is certified in real-time, maintaining unbroken chains of integrity evidence throughout the entire recording period, thus preventing any gaps in continuity verification.
3Reliability
If signature is applied to entire video data, then overall integrity is guaranteed, but privacy protection through sanitization becomes difficult
Solution Approach 1:
The video is divided into blocks, and only relevant blocks are included in the signature subject. When sanitization is needed, problematic segments can be excluded from the signature calculation without invalidating the entire video's certification. This segmentation enables selective integrity verification, maintaining both video integrity for certified portions and adaptability for privacy protection.
Solution Approach 2:
Different portions of the video can have different quality requirements. Blocks requiring privacy protection can be sanitized locally while other blocks maintain full integrity verification. The signature subject can be configured to include only specific blocks, allowing local quality adjustments for privacy without compromising overall system reliability or adaptability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system guarantees the integrity and continuity of video data, preventing falsification and ensuring that video evidence remains unaltered, even in the event of errors like power outages, thereby providing reliable third-party certification.
Implementation Method 1
generates frame digests using cryptographic hash functions
Data Source
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AI summary
A signature generating device (703) includes a receiving unit (701) configured to receive a sequence of data; a summary data generating unit (702) configured to sequentially generate summary data of the data upon reception of each of the data by the receiving unit (701); an obtaining unit (703) configured to sequentially obtain, when the number of data included in a sequence of the summary data generated by the summary data generating unit (702) reaches a given number, the sequence of the summary data as a block; a setting unit (704) configured to set, as a signature subject, a current block constituted by the sequence of the summary data, and the summary data selected from at least one block contiguous to the current block; a digital signature generating unit (705) configured to generate a digital signature concerning data summarized for the current block; and a sending unit (706) configured to send the generated digital signature, the signature subject associated with the digital signature, and the data summarized for the current block.