On Thursdays the USPTO publishes new patent applications. Today's Spotlight Applications concern aspects of digital fingerprinting and digital watermarking. Assigned to Dolby Labs, the first application discloses techniques for projection based hashing that balances robustness and sensitivity of media fingerprints. Assigned to Intertrust, the second aplication discloses techniques for software self-checking and tamper resistance.
20110299721, "Projection based hashing that balances robustness and sensitivity of media fingerprints," assigned to Dolby Labs.
Multiple candidate feature components of media content or projection matrices (or other hash functions, e.g., non-linear projections) are identified. Each of the candidate projection matrices (or other hash functions) includes an array of coefficients that relate to the candidate features. A subgroup of the candidate features or the projection matrices (or other hash functions) are selected based at least partially on an optimized combination of at least two characteristics of the candidate features or projection matrices (or other hash functions). Media fingerprints that uniquely identify the media content are derived from the selected optimized subgroup. Optimal projection matrices (or other hash functions) may be designed. Performance or sensitivity (e.g., search time) characteristics of the fingerprints are thus balanced with robustness characteristics thereof.
20110302424, "Software Self-Checking Systems and Methods," assigned to Intertrust.
Software self-checking mechanisms are described for improving software tamper resistance and/or reliability. Redundant tests are performed to detect modifications to a program while it is running. Modifications are recorded or reported. Embodiments of the software self-checking mechanisms can be implemented such that they are relatively stealthy and robust, and so that it they are compatible with copy-specific static watermarking and other tamper-resistance techniques.