Asymmetric Fingerprinting for Larger Collusions

Fingerprinting schemes deter people from illegally redistributing digital data by enabling the original merchant of the data to identify the original buyer of a redistributed copy. So-called traitor-tracing schemes have the same goal for keys that can be used to decrypt information that is broadcast in encrypted form. Recently, asymmetric fingerprinting and traitor-tracing schemes were introduced. Here, only the buyer knows the fingerprinted copy after a sale, and if the merchant finds this copy somewhere, he obtains a proof that he found the copy of this particular buyer. First contructions showed the validity of the concept. However, essentially all these constructions use so-called memory-less symmetric schemes as building blocks, whereas the better ones among the known symmetric schemes are not memory-less in this sense. Consequently, the previous asymmetric constructions did not reach the same level of tolerance against collusions as symmetric schemes. We now show asymmetric constructions without the restriction.

By: Birgit Pfitzmann and Michael Waidner

Published in: Proceedings of 4th ACM Conference on Computer and Communications Security. , New York, ACM, p.151-60 in 1997

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