Dynamic tardos traitor tracing schemes
AssigneeIrdeto B.V.
InventorsPeter Roelse, Jeroen Doumen, Thijs Laarhoven
Life of this patent
Estimating the term…
Abstract
A fingerprinting method. For each round in a series of rounds: providing to each receiver in a set of receivers a version of a source item of content, the source item of content corresponding to the round. For the round there is a corresponding part of a fingerprint-code for the receiver, the part includes one or more symbols. The version provided to the receiver represents those one or more symbols. One or more corresponding symbols are obtained from a suspect item as a corresponding part of a suspect-code. For each receiver in the set of receivers, a corresponding score that indicates a likelihood that the receiver is a colluding-receiver is updated.
Claims17
A fingerprinting method implemented by one or more computer processors, the method comprising,
- for each receiver in a set of receivers initializing a corresponding score that indicates a likelihood that the receiver is a colluding-receiver;
- and
- for each round in a series of rounds:
- providing to each receiver in the set of receivers a version of a source item of content, the source item of content corresponding to the round, wherein for the round there is a corresponding part of a fingerprint-code for the receiver, the part comprising one or more symbols, wherein the version provided to the receiver represents those one or more symbols;
- obtaining, from a suspect item of content one or more corresponding symbols as a corresponding part of a suspect-code;
- for each receiver in the set of receivers, updating the corresponding score that indicates a likelihood that the receiver is a colluding-receiver, wherein a colluding-receiver is a receiver that has been provided with a version of a source item of content that has been used to generate a suspect item of content, wherein said updating is based on the fingerprint-code for the receiver and the suspect-code wherein, when the round is not a first round, said updating is based on a value of the corresponding score in a previous round;
- for each receiver in the set of receivers, when the score for the receiver exceeds a threshold, updating the set of receivers by removing the receiver from the set of receivers so that the receiver is not provided with a further version of a source item of content, wherein the threshold is set such that the probability that a receiver that is not a colluding-receiver has a score exceeding the threshold is at most a predetermined probability.
An apparatus comprising one or more computer processors configured to carry out a fingerprinting operation, the one or more processors being configured to, for each receiver in a set of receivers initialize a corresponding score that indicates a likelihood that the receiver is a colluding-receiver;
- and for each round in a series of rounds:
- provide to each receiver in the set of receivers a version of a source item of content, the source item of content corresponding to the round, wherein for the round there is a corresponding part of a fingerprint-code for the receiver, the part comprising one or more symbols, wherein the version provided to the receiver represents those one or more symbols;
- obtain, from a suspect item of content one or more corresponding symbols as a corresponding part of a suspect-code;
- for each receiver in the set of receivers, update the corresponding score that indicates a likelihood that the receiver is a colluding-receiver, wherein a colluding-receiver is a receiver that has been provided with a version of a source item of content that has been used to generate a suspect item of content, wherein said updating is based on the fingerprint-code for the receiver and the suspect-code wherein, when the round is not a first round, said updating is based on a value of the corresponding score in a previous round;
- for each receiver in the set of receivers, when the score for the receiver exceeds a threshold, updating the set of receivers by removing the receiver from the set of receivers so that the receiver is not provided with a further version of a source item of content, wherein the threshold is set such that the probability that a receiver that is not a colluding-receiver has a score exceeding the threshold is at most a predetermined probability.
A non-transitory computer readable medium having instructions recorded thereon which, when executed by a processor, causes the processor to carry out a fingerprinting operation comprising, for each receiver in a set of receivers initializing a corresponding score that indicates a likelihood that the receiver is a colluding-receiver;
- and
- for each round in a series of rounds:
- providing to each receiver in the set of receivers a version of a source item of content, the source item of content corresponding to the round, wherein for the round there is a corresponding part of a fingerprint-code for the receiver, the part comprising one or more symbols, wherein the version provided to the receiver represents those one or more symbols;
- obtaining, from a suspect item of content one or more corresponding symbols as a corresponding part of a suspect-code;
- for each receiver in the set of receivers, updating the corresponding score that indicates a likelihood that the receiver is a colluding-receiver, wherein a colluding-receiver is a receiver that has been provided with a version of a source item of content that has been used to generate a suspect item of content, wherein said updating is based on the fingerprint-code for the receiver and the suspect-code wherein, when the round is not a first round, said updating is based on a value of the corresponding score in a previous round;
- for each receiver in the set of receivers, when the score for the receiver exceeds a threshold, updating the set of receivers by removing the receiver from the set of receivers so that the receiver is not provided with a further version of a source item of content, wherein the threshold is set such that the probability that a receiver that is not a colluding-receiver has a score exceeding the threshold is at most a predetermined probability.
Dependencies are inferred from the claim text.