Cryptology ePrint Archive: Report 2013/236

A Ciphertext-Policy Attribute-Based Proxy Re-Encryption with Chosen-Ciphertext Security

Kaitai Liang and Liming Fang and Duncan S. Wong and Willy Susilo

Abstract: Ciphertext-Policy Attribute-Based Proxy Re-Encryption (CP-ABPRE) extends the traditional Proxy Re-Encryption (PRE) by allowing a semi-trusted proxy to transform a ciphertext under an access policy to the one with the same plaintext under another access policy (i.e.attribute-based re-encryption). The proxy, however, learns nothing about the underlying plaintext. CP-ABPRE has many real world applications, such as fine-grained access control in cloud storage systems and medical records sharing among different hospitals. Previous CP-ABPRE schemes leave how to be secure against chosen-ciphertext attacks (CCA) as an open problem. This paper, for the first time, proposes a new CP-ABPRE to tackle the problem. The new scheme supports attribute-based re-encryption with any monotonic access structures. Despite our scheme is constructed in the random oracle model, it can be proved CCA secure under the decisional $q$-parallel bilinear Diffie-Hellman exponent assumption.

Category / Keywords: cryptographic protocols /

Date: received 23 Apr 2013

Contact author: kliang4-c at my cityu edu hk

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Version: 20130429:112621 (All versions of this report)

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