Cryptology ePrint Archive: Report 2015/836

Ciphertext-Policy Attribute-Based Broadcast Encryption with Small Keys

Benjamin Wesolowski and Pascal Junod

Abstract: Broadcasting is a very efficient way to securely transmit information to a large set of geographically scattered receivers, and in practice, it is often the case that these receivers can be grouped in sets sharing common characteristics (or attributes). We describe in this paper an efficient ciphertext-policy attribute-based broadcast encryption scheme (CP-ABBE) supporting negative attributes and able to handle access policies in conjunctive normal form (CNF). Essentially, our scheme is a combination of the Boneh-Gentry-Waters broadcast encryption and of the Lewko-Sahai-Waters revocation schemes; the former is used to express attribute-based access policies while the latter is dedicated to the revocation of individual receivers. Our scheme is the first one that involves a public key and private keys having a size that is independent of the number of receivers registered in the system. Its selective security is proven with respect to the Generalized Diffie-Hellman Exponent (GDHE) problem on bilinear groups.

Category / Keywords: public-key cryptography / broadcast encryption, attribute-based encryption

Date: received 28 Aug 2015

Contact author: pascal junod at heig-vd ch

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Version: 20150828:204623 (All versions of this report)

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