Coin-based anonymous fingerprinting

Abstract

Fingerprinting schemes are technical means to discourage people from illegally redistributing the digital data they have legally purchased. These schemes enable the original merchant to identify the original buyer of the digital data. In so-called asymmetric fingerprinting schemes the fingerprinted data item is only known to the buyer after a sale and if the merchant finds an illegally redistributed copy, he obtains a proof convincing a third party whom this copy belonged to. All these fingerprinting schemes require the buyers to identify themselves just for the purpose of fingerprinting and thus over the buyers no privacy. Hence anonymous asymmetric fingerprinting schemes were introduced, which preserve the anonymity of the buyers as long as they do not redistribute the data item. In this paper a new anonymous fingerprinting scheme based on the principles of digital coins is introduced. The construction replaces the general zero-knowledge techniques from the known certificate-based construction by explicit protocols, thus bringing anonymous fingerprinting far nearer to practicality.