A systematic review of lightweight cryptographic schemes for security and privacy in IoT

The rapid growth of the Internet of Things (IoT) has created significant challenges in safeguarding security and privacy in resource-constrained environments. Conventional encryption algorithms often impose heavy computational and energy costs, making them unsuitable for IoT devices. To address this, lightweight cryptographic schemes have been widely studied as efficient alternatives. This paper presents a Systematic Literature Review (SLR) following Kitchenham`s guidelines, analyzing 77 peer-reviewed studies published between 2006 and 2025. Both qualitative synthesis and quantitative evaluation (e.g., entropy, execution time, energy consumption, throughput, NPCR, UACI) are conducted. The review is guided by four research questions focusing on: (i) lightweight cryptographic techniques for confidentiality, integrity, and authentication; (ii) performance trade-offs in constrained IoT devices; (iii) optimizations of Elliptic Curve Cryptography (ECC); and (iv) integration with emerging technologies such as AI, blockchain, and steganography. The findings classify lightweight block and stream ciphers, hybrid frameworks, and authentication protocols while highlighting their strengths and limitations. The study also identifies research gaps, such as limited adaptive models and insufficient benchmarking on embedded platforms. This work contributes a clear roadmap for designing secure, scalable, and energy-efficient cryptographic solutions tailored for IoT ecosystems, thereby guiding both academic research and real-world deployment.