An Efficient and Secure Lightweight Certificateless Hybrid Signcryption Scheme

With the limited resources of the Internet of Things (IoT), security and efficiency have become a challenge. The hybrid signcryption scheme is a proper method to ensure data security and integrity. Recently, through continuous and in-depth research, the signcryption scheme has made many achievements, but there are still some problems. Most proposals use bilinear mapping, which reduces computational efficiency. It brings a heavy burden to the resource-constrained IoT. And many constructions cannot meet the claimed security, causing the leakage of private messages. Therefore, we propose a lightweight certificateless hybrid signcryption (CLHS) scheme with better performance and higher security to solve the above problems. First, we have reduced storage pressure and improved computational efficiency by using certificateless public-key cryptography and elliptic curves instead of bilinear maps to construct a signcryption scheme, and the construction is lightweight. At the same time, to securely transmit messages of different lengths, we employ a hybrid signcryption scheme. Through formal security proof, efficiency, and performance analysis, our proposal has the security requirements of confidentiality and unforgeability and has better computational efficiency and security performance. Finally, we propose a secure data transmission protocol based on our CLHS scheme in Smart Grid, which inherits the advantages of high computational efficiency and better security of the underlying CLHS scheme.