Fully Collusion Resistant Traitor Tracing With Short Ciphertexts and Private KeysAuthors: D. Boneh, A. Sahai, and B. Waters
We construct a fully collusion resistant tracing traitors system with sublinear size ciphertexts and constant size private keys. More precisely, let N be the total number of users. Our system generates ciphertexts of size O(sqrt(N)) and private keys of size O(1). We first introduce a simpler primitive we call private linear broadcast encryption (PLBE) and show that any PLBE gives a tracing traitors system with the same parameters. We then show how to build a PLBE system with O(sqrt(N)) size ciphertexts. Our system uses bilinear maps in groups of composite order.
In proceedings of Eurocrypt '06, LNCS 4004, 2006, pp. 573-592
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