Efficient asymmetric self-enforcement scheme with public traceability

Abstract

Traitor tracing schemes deter traitors from giving away their keys to decrypt the contents by enabling the data supplier to identify the source of a redistributed copy. In asymmetric schemes, the supplier can also convince an arbiter of this fact. Another approach to the same goal was suggested by Dwork, Lotspiech and Naor, so called self-enforcement schemes. In these schemes, traitors have to either divulge their private sensitive information or distribute fairly large amount of data. However, the same private information must be revealed to the data supplier, which invokes the necessity of more discussion about the model underlying this scheme. In this paper, we present an efficient asymmetric self-enforcement scheme, which also supports the asymmetric traceability without any trusted third parties, assuming the situation where the authenticity of the exponent of each subscriber’s sensitive information bound to the subject entity is publicly certified, such as PKI derived from discrete logarithm based cryptosystems. In our scheme, the sensitive information needs not to be revealed to any entities. As far as we know, there has never been any proposal of asymmetric self-enforcement schemes. Furthermore, our scheme is as efficient as the previous most efficient symmetric or asymmetric traitor tracing schemes proposed so far.