Cryptology ePrint Archive: Report 2007/404

Predicate Encryption Supporting Disjunctions, Polynomial Equations, and Inner Products

Jonathan Katz and Amit Sahai and Brent Waters

Abstract: Predicate encryption is a new paradigm generalizing, among other things, identity-based encryption. In a predicate encryption scheme, secret keys correspond to predicates and ciphertexts are associated with attributes; the secret key SK_f corresponding to the predicate f can be used to decrypt a ciphertext associated with attribute I if and only if f(I)=1. Constructions of such schemes are currently known for relatively few classes of predicates.

We construct such a scheme for predicates corresponding to the evaluation of inner products over N (for some large integer N). This, in turn, enables constructions in which predicates correspond to the evaluation of disjunctions, polynomials, CNF/DNF formulae, or threshold predicates (among others). Besides serving as what we feel is a significant step forward in the theory of predicate encryption, our results lead to a number of applications that are interesting in their own right.

Category / Keywords: public-key cryptography /

Date: received 15 Oct 2007, last revised 7 Jul 2008

Contact author: bwaters at csl sri com

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Version: 20080708:003105 (All versions of this report)

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