Patent ID: 7046818

Claim:
A method for inserting a watermark in digital data that comprises a plurality of blocks of coded transform coefficients, each block containing one of a first type of coefficient and a plurality of a second type of coefficient, the method comprising the step of: applying a scrambling algorithm to each block in a predetermined pattern area of the digital data to insert the watermark in the digital data such that the resulting watermarked digital data is format compliant, the scrambling algorithm being applied by performing at least one of the following scrambling operations: (i) for at least some of the blocks in the pattern area, XORing magnitude bits of each of selected ones of the second type of coefficient with a pseudo random number, (ii) for a select number of pairs of blocks in the pattern area, swapping the plurality of second type coefficients from one block in each pair with the plurality of second type coefficients from the other block in the pair, (iii) for blocks in a first sequence of blocks in the pattern area, shuffling differential values of the first type of coefficient among blocks in the first sequence, or (iv) for blocks in a second sequence of blocks in the pattern area, shuffling select bits of the first type of coefficient, but not of the second type of coefficient, among blocks in the second sequence.