CPC H04L 9/0869 (2013.01) [H04L 9/0618 (2013.01); H04L 2209/608 (2013.01)] | 20 Claims |
13. A system for detecting and/or verifying a watermark in a file, the system comprising:
a processor; and
memory storing instructions executable by the processor to:
generate, using information derived from a secret key associated with the watermark, a first random seed;
generate, using the first random seed, an ordered pseudorandom set of integers;
generate, using entity information for at least one entity to which the file was distributed and timing information corresponding to a validity time period for the file, a second random seed;
select, using the second random seed, a subset of the ordered pseudorandom set of integers, the subset corresponding to identifiers of data locations in the file;
generate a sequence of watermark elements, the watermark elements comprising expected values for associated locations in the file, the associated locations being selected based on the first random seed and the expected values being selected based on the second random seed; and
compare the sequence of watermark elements to the file to determine whether the associated locations in the file are populated with the respective associated expected values.
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