Key Policy Attribute-based Proxy Re-encryption and RCCA Secure Scheme

Cloud computing has come into our daily lives. The cloud server can provide powerful computing and storage capability as services. Since the decryption algorithm for attribute-based encryption needs a lot of computations, so with the help of cloud servers many attribute-based encryption schemes are designed for practical applications in cloud computing. To the best of our knowledge there does not exist any flexible key policy attribute-based proxy re-encryption (KP-AB-PRE) scheme with matrix access structure. In this paper, we present a KP-AB-PRE scheme, in which the cloud server can function as a proxy and deal with the attribute-based encryption (ABE) ciphertexts directly. In the proposed scheme, the key policy is matrix access structure. We will prove our scheme in the replayable adaptively chosen ciphertext attack (RCCA) security model. Our construction enjoys the desirable properties of unidirectional, non-interactive, and multi-use, and the secret key security is guaranteed.