SLIE: A Secure and Lightweight Cryptosystem for Data Sharing in IoT Healthcare Services

The Internet of Medical Things (IoMT) has revolutionized healthcare by transforming medical operations into standardized, interoperable services. However, this service-oriented model introduces significant security vulnerabilities in device management and communication, which are especially critical given the sensitivity of medical data. To address these risks, this paper proposes SLIE (Secure and Lightweight Identity Encryption), a novel cryptosystem based on Wildcard Key Derivation Identity-Based Encryption (WKD-IBE). SLIE ensures scalable trust and secure omnidirectional communication through end-to-end encryption, hierarchical access control, and a lightweight key management system designed for resource-constrained devices. It incorporates constant-time operations, memory obfuscation, and expiry-based key revocation to counter side-channel, man-in-the-middle, and unauthorized access attacks, thereby ensuring compliance with standards like HIPAA and GDPR. Evaluations show that SLIE significantly outperforms RSA, with encryption and decryption times of 0.936ms and 0.217ms for 1KB of data, an 84.54% improvement in encryption speed, a 99.70% improvement in decryption speed, and an energy efficiency of 0.014 J/KB.