A New Identity-Based Encryption Scheme with Accountable Authority Based on SM9

Accountable authority identity-based encryption (A-IBE) is an extension of identity-based encryption (IBE) in which private key’s source can be traced, i.e., whether the key comes from a private key generator or a user. SM9 is an official cryptography standard of China which defines a practical IBE scheme. In this paper, we construct a practical A-IBE scheme from the SM9-IBE scheme. Our A-IBE scheme has public traceability and is proven secure if the based SM9-IBE scheme is secure. Compared with other A-IBE schemes, our A-IBE scheme has better efficiency in encryption and decryption.