UNAUTHORIZED USER DETECTING DEVICE, COLLUSION-SECURE CODE GENERATING DEVICE, AND PROGRAM

摘要

PPROBLEM TO BE SOLVED: To provide an unauthorized user detecting technology for discriminating an unauthorized user who generates digital contents illegally, even if not all the collusion-secure codes embedded in the digital contents are extracted. PSOLUTION: A threshold value setting part 101 sets a threshold value used for determining whether a user is an unauthorized user or not, based on the code length of a collusion-secure code extracted by a code extracting part. A score calculating part 102 calculates a score for each user using all or a part of the collusion-secure codes extracted by the code extracting part as well as the code assigned to each user. An unauthorized user determining part 103 determines whether each of users is an unauthorized user or not using the score of each user calculated by the score calculating part 102 and the threshold value set by the threshold value setting part 101. PCOPYRIGHT: (C)2009,JPO&INPIT