Patent ID: 8171294

Claim:
An additional-information detection processing apparatus comprising: a receiver configured to receive a content including additional information superimposed thereon and to detect the additional information that includes i) an identifier of a user; ii) a content identifier unique to the content; and iii) a plurality of delivery service provider identifiers, each of the plurality of delivery service provider identifiers corresponding to a delivery service provider that distributes the content along a portion of a content distribution route; a memory configured to receive and to store correspondence information indicating a correspondence among an identifier of a user who is authorized to receive the content, the content identifier unique to the content, and the plurality of delivery service provider identifiers; a data verifier configured to detect illegal tampering or distribution of the content by comparing the identifier of the user in the additional information detected by said receiver with the identifier of the user who is authorized to receive the content in the correspondence information, and comparing the plurality of delivery service provider identifiers in the additional information detected by said receiver with the plurality of delivery service provider identifiers in the correspondence information, the correspondence information being stored in a delivery record table connected to the data verifier; and a detecting processor configured to detect the superimposed additional information, and to calculate an inner product of at least a portion of the detected superimposed additional information and a random number, the random number having been used to encode the portion of superimposed additional information, to generate a probability density function of the product, wherein the data verifier detects illegal tampering or distribution of the content based on a comparison of the generated probability density function with a predetermined threshold.