Patent ID: 7711114

Claim:
A method of assigning sequence keys to a content file, to enable tracing, comprising: identifying one of a plurality of first sequence numbers and one of a plurality of first sequence keys for a content file; identifying a number of first content file variations the content file is capable of supporting by processing with a computer processor on a computer; assigning a variation number and one or more of the first sequence keys and one or more of the first sequence numbers to each of the first content file variations; assigning an outer code to the first sequence keys; generating a variation table having a plurality of entries, the variation table for mapping the first sequence keys to the first content file variations; wherein a first entry in the variation table contains one of the first content file variations corresponding to at least one of the first sequence keys; encrypting a first variation number and storing the first variation number in the variation table; identifying a critical segment which contains some of the first content file variations; creating an inner code table with an entry for the critical segment; encrypting the inner code table with a variation key from the variation table; encrypting the first entry in the variation table with a value associated with the corresponding assigned one of the first sequence keys.