Adaptive Traitor Tracing via Inner Outer Code Segmentation

The patent segments the code into inner code and outer code components. The inner code uses a limited alphabet size (q) for compact representation, while the outer code operates on sequences of inner code symbols. This segmentation allows the system to achieve traceability for large coalitions (up to q log q traitors) without requiring a proportional increase in the inner code alphabet size, thus controlling bandwidth consumption while maintaining measurement precision.

The patent transitions from a single-dimensional approach (increasing alphabet size q) to a two-dimensional approach using inner code and outer code. The inner code maintains a small alphabet for bandwidth efficiency, while the outer code provides the additional dimension by operating on sequences of inner code symbols. This dimensional expansion enables the system to trace coalitions larger than q without increasing the inner code alphabet size, resolving the contradiction between bandwidth efficiency and traceability.

The patent segments the detection process into two levels corresponding to the inner and outer codes. The inner code provides compact symbol representation, while the outer code enables efficient detection of large coalitions by operating on sequences of inner code symbols. This segmented approach maintains relative simplicity in detection algorithms while significantly improving traceability for large numbers of traitors, overcoming the limitations of straightforward scoring methods.