New patents are issued by the PTO on Tuesdays. Both of today's Spotlight Patents concern aspects of digital watermarking. Assigned to Stegosystems, Inc., the first patent addresses techniques for a steganographic messaging system using code invariants. Assigned to HBO, the second patent addresses techniques for watermarking content for tracking media consumption.
8,958,546, "Steganographic messaging system using code invariants," assigned to Stegosytems, Inc.
A steganographic method to prevent the execution of malicious code and mitigate software piracy. The method uses invariant portions of machine instructions to create an executable watermark within unmodified code. This watermark can be verified at any stage of the software lifecycle, including dynamically and continuously during execution, to detect foreign code by verifying the integrity of the watermark prior to execution. In addition, the watermark may serve as a steganographic covert channel concealing additional information. Code invariants are not altered by binding operations such as loading and linking on different machines, and thus may be employed to consistently and repeatedly identify an unmodified instantiation of a particular program. The use of opcodes and register references as invariants avoids trivial register substitution as a means of program differentiation that eludes detection. The split key structure of the resulting cipher implies that knowledge of only the code (first key) or the cipher table (second key) alone is insufficient to derive the message.
8,954,743, "System and method for watermarking content for tracking media consumption," assigned to Home Box Office, Inc.
In a system and method of watermarking content for tracking media consumption, the method may include creating, by a computer processor, at least one copy of a mezzanine asset for distribution to at least one user, the mezzanine asset being watermarked with a watermark identifier, and the at least one copy including a copy of the watermark identifier.