An Efficient Signcryption for Internet of Health Things over Satellite Terrestrial Integrated Networks

The rapid growth of Internet of Health Things (IoHT) devices has introduced serious security issues in healthcare settings, where securing data confidentiality, integrity, and authentication is essential. The proliferation of Satellite Terrestrial Integrated Networks (STINs) further amplifies these security concerns, as IoHT devices increasingly rely on hybrid satellite-terrestrial links for remote patient monitoring in underserved and emergency response environments, where channel heterogeneity and long propagation delays make traditional cryptographic overhead particularly costly. In addition, managing computational complexity, communication overhead, and memory usage presents a further challenge for resource-limited IoHT devices. This paper presents a novel certificateless signcryption scheme that integrates Certificateless Public Key Cryptography with Hyperelliptic Curve Cryptography (HEC) to address these challenges. The proposed scheme operates over a genus-2 hyperelliptic curve with an 80-bit security parameter, achieving a key size of only 240 bits 50% smaller than leading ECC-based schemes. Experimental evaluation on a MacBook Pro (Intel Core i5, 1.4 GHz) as sender and Raspberry Pi 4 (ARM Cortex-A72, 1.5 GHz) as receiver demonstrates that the complete signcryption and unsigncryption cycle completes in 0.001934 s, representing a 99.5% reduction compared to the best competing ECC-based existing scheme and a 99.99% reduction compared to the best pairing-based existing scheme. Communication overhead is reduced to only 2448 bits 14% lower than leading ECC-based approaches and 80% lower than pairing-based schemes. We conduct thorough security assessments through both formal and informal analyses, demonstrating that our scheme satisfies IND-CCA2 confidentiality and EUF-CMA unforgeability under the DDH and CDH hardness assumptions, and resists forgery, impersonation, replay, and man-in-the-middle attacks. Formal verification using the AVISPA tool with OFMC and CL-AtSe back-ends confirms the protocol’s security. Performance evaluation confirms our scheme is particularly suitable for resource-constrained IoHT devices operating over STINs, offering an optimal balance between security assurance and computational efficiency.