Blockchain technology offers immutable evidence in decentralized data management in modern medical systems. However, securing Electronic Medical Records (EMR) within the blockchain framework remains a critical challenge due to the inherent storage limitations and computational overhead from existing public key methods. To address such issues, this paper proposes a certificateless hybrid signcryption scheme that integrates a tag-based key encapsulation mechanism (tag-KEM) with a data encapsulation mechanism (DEM), to enable secure and efficient EMR data management. Our approach addresses key limitations in existing blockchain systems by combining lightweight cryptographic operations based on Elliptic Curve Cryptography(ECC) with efficient decentralized off-chain storage to accommodate large-scale on growing health data. By employing ECC operations, the scheme significantly reduces computational complexity and enhances blockchain transaction throughput. Results from our experimental analysis shows a 40.01%–97.71% reduction in computational cost compared to the other existing methods. Additionally, findings from the decentralized off-chain analysis indicate significant improvements in storage efficiency and system performance, underscoring the scheme’s practicality for real-world data security applications.

Precision agriculture (PA) involves collecting, processing, and analyzing datasets in agriculture for an informed decision. Due to the high data storage and application maintenance costs, farmers usually outsource their agricultural data obtained from PA to cloud service providers to leverage cloud services. Nonetheless, serious security concerns arise from using cloud services for farmers. For instance, an attacker can intercept agricultural data and run comprehensive statistical analyses to adjudicate farmers’ financial status, extort money, commit identity theft, etc. As a result, compelling data security schemes have become crucial for secure precision farming, where only legitimate users are required to access the agricultural data outsourced to the cloud. This article presents a certificateless signcryption scheme with proxy re-encryption (CLS-PRE) for secure access control in PA. An in-depth security analysis proves that the CLS-PRE scheme is secure in the Random Oracle Model. Detailed performance evaluation also shows that the scheme can reduce the time required to signcrypt and unsigncrypt messages and lower communication overhead.

Current trends of mobile technology have seen a tremendous growth in its application in smart healthcare. This has resulted in the adoption and implementation of mobile health (m-health) systems by providing health assistance to the aging population. Despite its advantageous benefits, its computational complexities cannot be overlooked. M-health devices are portable processing tiny equipment with limited computational capabilities thereby making them complex for the implementation of public key cryptosystems. In spite of this, an Offline-Online signature scheme called the MHCOOS has been proposed to solve the difficulties in the computational ability. The scheme enjoys the following benefits by splitting the signing part into both offline and online phases. The offline phase performs heavy computations when a message is absent, whereas lighter computations are performed at the online stage when a message is present. Secondly, the online computations are extremely fast due to the already computed offline signature value and lighter pairings involved. Our performance analysis demonstrates how the proposed scheme outperforms other schemes. Finally, the hardness of the scheme is proven under the Bilinear Diffie–Hellman (BDH) and Computational Diffie–Hellman (CDH) problem in the random oracle model.