An efficient hierarchical identity-based encryption based on SM9
Scientia Sinica Informationis
Hierarchical identity-based encryption can efficiently reduce the workload of private key generation and key distribution of the private key generator in the identity-based cryptography. SM9 is an identity-based cryptosystem and has become a Chinese cryptographic standard and national standard. It plays a significant role in many applications, such as finance and government affairs. However, SM9 encryption algorithm does not support hierarchical encryption, which is undesirable for the large network and becomes a bottleneck for its deployments. In this paper, we proposed an efficient hierarchical identity-based encryption scheme SM9-HIBE based on SM9. Compared to SM9 encryption algorithm, the ciphertext in SM9-HIBE only requires an additional group element and the decryption overhead increases one pairing operation only, which is independent of the length of receiver’s identity. We prove that if the DBDHI assumption holds, our scheme is proved to be IND-sCPA secure in the random oracle model. Finally, we theoretically analyze our scheme and make a comparison. The result shows that the SM9-HIBE is comparable to the existing HIBE schemes in terms of computational cost and communication overhead.
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