Cryptology ePrint Archive: Report 2009/371

Attribute-Sets: A Practically Motivated Enhancement to Attribute-Based Encryption

Rakesh Bobba and Himanshu Khurana and Manoj Prabhakaran

Abstract: In distributed systems users need to share sensitive objects with others based on the recipientsí ability to satisfy a policy. Attribute-Based Encryption (ABE) is a new paradigm where such policies are specified and cryptographically enforced in the encryption algorithm itself. Ciphertext-Policy ABE (CP-ABE) is a form of ABE where policies are associated with encrypted data and attributes are associated with keys. In this work we focus on improving the flexibility of representing user attributes in keys. Specifically, we propose Ciphertext Policy Attribute Set Based Encryption (CP-ASBE) - a new form of CP-ABE - which, unlike existing CP-ABE schemes that represent user attributes as a monolithic set in keys, organizes user attributes into a recursive set based structure and allows users to impose dynamic constraints on how those attributes may be combined to satisfy a policy. We show that the proposed scheme is more versatile and supports many practical scenarios more naturally and efficiently. We provide a prototype implementation of our scheme and evaluate its performance overhead.

Category / Keywords: public-key cryptography / Attribute-Based Encryption

Date: received 27 Jul 2009, last revised 27 Jul 2009

Contact author: rbobba at illinois edu

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Version: 20090731:005050 (All versions of this report)

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