A cloud data sharing scheme by using SM2 ring signature-based broadcast encryption

Amidst the surge of cloud computing, cloud-based data sharing has been broadly used. However, in cloud-based sharing, it is necessary to ensure data reliability, guarantee data integrity and protect user’s identity. Although traditional ring signature algorithms can provide strong data reliability and privacy protection, it is difficult to arbitrate the true identity of the signer. In this paper, we propose a SM2 ring signature broadcasting encryption scheme which is suitable for secure cloud data sharing. By introducing a third party, we generate a signer’s identity label that serves as an important parameter for the SM2 ring signature when we generate the signature value and revocation label. Meanwhile, we design a revocation mechanism that allows the third party to execute a revocation anonymity algorithm by using the revocation label to expose the signer’s identity. Moreover, any member can also check whether the third party has acted maliciously through the revocable anonymity label. Furthermore, we use the proposed signature broadcasting encryption scheme to achieve data sharing with data integrity, unforgeability, anonymity, revocable anonymity and ciphertext indistinguishability. Finally, we provide the experimental results to show the efficiency and practicability of our proposed scheme.