LFSR Watermark Authentication for False Accusation Prevention
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Solution Overview
Problem
In digital watermarking, errors during detection or framing attacks can falsely accuse innocent consumers of media content leakage, and collusion between users can implicate others illegitimately.
Innovation Solution
A system utilizing a linear feedback shift register (LFSR) to embed and detect watermarks in media content, with an assurance value to authenticate the information element, ensuring accurate identification and authentication of the watermark, even in the presence of errors or missing data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If watermark detection is performed without authentication mechanism, then detection speed is improved, but false accusation rate increases
Solution Approach 1:
The patent embeds an authentication value together with the watermark information during the embedding process. This preliminary action of including authentication data from the beginning prevents false accusations without slowing down the detection process, as the authentication value is extracted and verified as part of the standard detection flow.
2Reliability
If authentication value is embedded in the watermark, then reliability of traitor tracing is improved, but watermark capacity is reduced
Solution Approach 1:
The patent uses a linear feedback shift register to generate the watermark sequence, which allows for efficient use of the available bits. The authentication value is integrated into the same bit stream as the watermark information, utilizing the temporal correlation between bits to convey both types of information without requiring separate dedicated spaces, thus minimizing the impact on overall capacity.
3Measurement precision
If LFSR-based watermarking is used, then accuracy of information extraction is improved, but system complexity increases
Solution Approach 1:
The patent employs a linear feedback shift register that uses feedback from previously extracted bits to regenerate the watermark sequence. This feedback mechanism enables accurate extraction of embedded information by continuously adjusting the reconstruction process based on received data, improving accuracy while the structured nature of the feedback loop keeps the implementation relatively simple.
Data Source
AI summary
In one embodiment, a system including a processor is operative to receive a content item including a watermark encoding a series of data values of an output stream of a linear feedback shift register initialized with a seed including an information element and an assurance value, the shift register having a plurality of states each including a first and second value, identify at least part of the watermark in the content item, extract at least some of the data values from the at least part of the identified watermark, process at least some of the extracted data values yielding the initial state of shift register, and authenticate the first value of the initial state using the second value of the initial state in order to confirm that the first value is indeed the information element included in the seed processed by the shift register.