Abstract:

In order to solve the problem of key escrow and the efficiency of attribute revocation in ABE, this paper proposes an attribute-based encryption revocation scheme that supports decryption outsourcing and no key escrow. In the scheme, if a user’s attribute is revoked, the attribute authority first generates a sibling intractable function based on the latest attribute update key and broadcasts it to users who have not revoked the attribute. Then the users update their own private key by using the sibling intractable function. Finally, the attribute authority updates the ciphertext in the cloud server according to the attribute update key to realize the attribute revocation. In the process of attribute revocation, this scheme reduces the computation and communication of the attribute authority, and uses semi-honest cloud server to perform partial decryption to reduce the computation of the user, and introduces the central authority and the attribute authority to jointly generate the user’s private key to solve the key escrow problem. The security proof and performance analysis show that, the scheme is based on the assumption of q-Parallel BDHE to achieve the chosen plaintext security under the standard model, which has higher computational efficiency than similar schemes.

Key words: attribute revocation, key escrow, decrypt outsourcing, sibling intractable function