Prediction-Coded Video Signing With Reduced-Length Frame Hashes
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Solution Overview
Problem
Existing video transmission methods using digital signatures for frame authentication result in increased bit rates due to the use of longer hashes for security, which complicates data transmission.
Innovation Solution
A method for signing prediction-coded video data involves generating a group hash and individual hashes of frame subsets, reducing the length of the individual hashes while maintaining security by using a high-security hashing scheme, and transmitting the group hash and reduced-length individual hashes along with the coded video sequence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If longer hashes are used for digital signature, then security level is improved, but bit rate increases
Solution Approach 1:
The patent segments the hash verification process into two distinct levels: individual frame hashes and group hashes. Individual hashes use reduced length for low-security frames to minimize bit rate, while group hashes provide comprehensive security coverage. This segmentation allows different security levels to be applied differentially, resolving the contradiction between security and bit rate.
Solution Approach 2:
The patent applies local quality by assigning different hash lengths to different frames based on their security requirements. Critical frames (I-frames, key frames) receive full-length or longer hashes for high security, while non-critical frames (P-frames, B-frames) receive reduced-length hashes. This localized approach optimizes the overall bit rate while maintaining necessary security at each position.
2Reliability
If list of hashes is transmitted for each video frame, then frame authentication is improved, but data transmission volume increases
Solution Approach 1:
The patent merges individual frame hashes with group hashes into a unified authentication structure. Instead of transmitting separate authentication data for each frame, the system combines them where group hashes serve multiple frames. This merging reduces redundant data transmission while maintaining the ability to authenticate individual frames through the hierarchical structure.
Solution Approach 2:
The patent applies partial action by transmitting reduced-length hashes for non-critical frames where full security is not required. For frames where complete authentication is less critical, shorter hashes suffice, providing partial but adequate security while significantly reducing data transmission volume. This selective approach optimizes the balance between authentication capability and bandwidth usage.
Data Source
AI summary
A method of signing prediction-coded video data comprises: obtaining a coded video sequence comprising a set of frames including at least one intra frame having independently decodable image data, and at least one inter frame, containing image data decodable by reference to another frame; generating a group hash of the coded video sequence by hashing the image data of the coded video sequence; generating a plurality of individual hashes of frame subsets including at least one frame by hashing the image data derived from each of the frame subsets, reducing the length of each of the individual hashes to a length shorter than a total length of the group hash, generating a digital signature by encrypting at least the group hash and the individual hashes with reduced lengths; providing the group hash and the reduced length individual hashes together with the digital signature and the coded video sequence.