Internet of Things (IoT) Current Research Challenges and Opportunities and Blockchain As A Potential Solution: A Review

The Internet of Things (IoT) is transforming the physical and digital worlds. Our everyday objects are transformed into smart devices, from dustbins to toothbrushes. In spite of the IoT being relatively young, its growth is brisk. By 2025, it is expected that 80 billion IoT devices will be used in practice. This would not be possible without addressing the challenges associated with the IoT. By using a state-of-the-art survey, this paper explores recent research topics related to IoT, such as scalability, energy efficiency, M2M communications, communication protocols, interoperability, heterogeneity, security, and privacy. Survey results reveal that security and privacy are identified by the majority of researchers as major research challenges. Subsequently, this paper explores the recent security trends such as AES, DES, RSA, BLOWFISH, DH, SHA-1/SHA-256, NTRU, hybrid security techniques, fog computing, edge computing, software-defined networking, lightweight cryptography, homomorphic and searchable encryption, machine learning-based solutions, blockchain-based solutions, and IOTA. Blockchains are unique in their properties such as immutability, trust, privacy, integrity, and resiliency, which isolate the technology from other existing security solutions and place it among the potential security solutions among existing trends. In addition to this overview of blockchain technology, applications of blockchain in IoT and the architecture of IoT with blockchain are also presented. Finally, the challenges of integrating Blockchain technology with IoT such as scalability, security, the privacy of information, smart contracts, legal issues, throughput, latency, computational requirements, and storage with solutions were discussed, along with future directions of research while designing Blockchain-based IoT applications with low power consumption and high scalability.