Ciphertext-Policy Attribute-Based Proxy Reencryption (CP-ABPRE) has found many practical applications in the real world, because it extends the traditional Proxy Reencryption (PRE) and allows a semitrusted proxy to transform a ciphertext under an access policy to the one with the same plaintext under another access policy. The existing CP-ABPRE schemes were proven secure only in the selective security model, a limited model, which is an unnatural constraint on the attacker. The scheme proved in this model can only be called selectively secure one. However, from a security perspective, the adaptively secure CP-ABPRE scheme is more desirable. In this paper, an adaptively secure CP-ABPRE scheme is proposed, which is based on Waters&#x2019; dual system encryption technology. The proposed scheme is constructed in composite order bilinear groups and proven secure under the complexity assumptions of the subgroup decision problem for 3 primes (3P-SDP). Analyses show that our proposal provides higher computational efficiency compared with the existing schemes.
['Huixian Li', 'Liaojun Pang']
Efficient and Adaptively Secure Attribute-Based Proxy Reencryption Scheme