Almost IPP-codes or provably secure digital fingerprinting codes

Codes with the Identifiable Parent Property (IPP codes) form a very useful tool in traitor tracing schemes since they guarantee (with probability 1) identification of at least one of the traitors. We consider a natural generalization of IPP codes, namely codes for which this property holds with probability close to 1. A probabilistic version of the IPP problem has been studied under the name of collusion-secure digital fingerprinting codes. We point out that, somewhat surprisingly, fingerprinting codes do no automatically have the “almost IPP property.”