Patent ID: 8825846

Claim:
A computer-implemented method for generating a plurality modified copies of a source file storing digital media content: generating each respective modified copy by: determining an initial, unmodified portion of the modified copy, wherein the initial, unmodified portion is set to a first point in the source file in a first modified copy and incremented by a specified amount for each successive modified copy, up to a second point in the source file and wherein each modified copy is assigned a unique identifier, and following the initial unmodified portion, generating an alternating sequence of modified and unmodified portions, based on a fixed modification size, until reaching an end point in the source file, wherein each modified portion degrades a playback quality of the digital media content and wherein each of the plurality of modified copies share at least one portion of modified content in common, such that a complete, unmodified copy of the source file cannot be reconstructed from the plurality of modified copies; and tracing at least one of the modified copies spreading from one location to another location using the unique identifier.