A heterogeneous signcryption scheme for smart grid with trusted multi-ciphertext equality test

Energy utilization rates have been largely improved thanks to the wide application of smart grids, thereby realizing the reliable, economic and efficient operation of the grids. However, such an application is also accompanied by many security issues. In response to the many problems within existing security schemes, such as not supporting the communication between heterogeneous cryptosystems, low security levels and a low data retrieval efficiency, a heterogeneous signcryption (HSC) scheme that supports a trusted multi-ciphertext equality test (MET) is proposed. The adoption of the HSC helps to identify secure communications from identity-based cryptosystems to certificateless cryptosystem, eliminates the certificate management problems in the traditional public key cryptography scheme, and ensures the confidentiality and authentication of power data. The introduction of the MET technology can avoid the high cost of equality test calculations after grouping ciphertexts in pairs. Using blockchain and smart contract technologies ensure the credibility of test results and eliminates the reliance on trusted cloud servers. Under the random oracle model, on the basis of the bilinear Diffie-Hellman, the computational Diffie-Hellman and the q-strong Diffie-Hellman problems, this paper proves that the scheme proposed herein meets the requirements of indistinguishability and one-way security under adaptive choice ciphertext attacks, and the unforgeability under the adaptive choice message attack. From the findings of the analysis, it has been shown that the proposed scheme satisfies more security attributes and requires lower computational overhead compared to similar schemes.