Heterogeneous Signcryption with Equality Test for IIoT environment

The existing signcryption schemes with equality testing are aimed at a sole cryptosystem and not suitable for the sophisticated heterogeneous network of Industrial Internet of Things (IIoT). To deal with this challenge, we propose a heterogeneous signcryption scheme with equality test (HSC-ET) in this article. This scheme enables a sensor in public key infrastructure (PKI) to execute data encryption and deliver it to the semi-trusted entity (cloud server). When a user in identity-based cryptosystem (IBC) intends to search some data stored on the cloud server. The delegated cloud server executes tests on ciphertexts for determining whether the same underlying plaintext exists between the two ciphertexts. These two ciphertexts can be one signcrypted ciphertext and one encrypted ciphertext, or both encrypted / signcrypted ciphertext, thus achieving flexible search to the ciphertext. HSC-ET is demonstrated to be secure by the rigorous and detailed analysis. And the experimental simulation and analysis results show the efficiency of our scheme.