Combinatorial Optimization of Countermeasures against Illegal Copying

The growth of the Internet has lead to an increase in the distribution on digital contents, such as music, still pictures, and motion pictures through networks. However, it has also lead to an increase in illegal copying without permission from the copyright holder. Although a number of countermeasures against illegal copying have been developed including watermarking and contents capsulation, it is impossible to find one perfect countermeasure. A method is needed that would allow for an optimal combination of different countermeasures to substantially reduce the probability of illegal copying. We propose such a method based on combinatorial optimization and fault-tree analysis. We use this method for a number of cases and show the actual optimal combinations for each case, as well as a flow chart for selecting a proper combination of countermeasures depending on the situation.