scalable network, especially to devices with resource constraints. This paper proposes a blockchain-based

secure communication model in IoT networks of the next generation, combining decentralized authentication,

lightweight consensus, smart contract-based access control, as well as edge/fog computing. The framework is

divided into four layers: IoT Device Layer, Edge/Fog Layer, Blockchain Layer, and Application Layer that

guarantee secure generation of data, preprocessing, validation of transactions, and real-time monitoring. An

implementation of a prototype based on Hyperledger Fabric and NS-3 was performed and tested in terms of

latency, throughput, energy use, smart contract execution time and time to validate a transaction. The findings

indicate that the latency decreased by 145ms to 120ms, throughput increased by 80 to 92 transactions/sec,

energy consumption dropped by 1.20W to 0.95W per device, smart contract execution time dropped by 40ms

to 30ms, and transaction validation time dropped by 50ms to 40ms with six consecutive epochs. Real-time

The Internet of Things (IoT) is spreading very quickly and transformed the current communication structure

through the interconnection of billions of devices in various fields, including healthcare, transport, industry,

and smart cities (Cherbal et al., 2024). The machines constantly produce and communicate a lot of sensitive

information and allow automation, real-time tracking, and decision-making. Nevertheless, the rising

multidimensionality and heterogeneity of IoT networks have presented grave security issues. Conventional

centralized security schemes are often unable to offer a high level of authentication, data integrity, and

confidentiality at scale, exposing the systems to attacks such as data manipulation, eavesdropping, DDoS, and

unauthorized access (Tawalbeh et al., 2020).

The blockchain technology has become a breakthrough towards removing such limitations by adding

networks, where scalability, autonomy, and interoperability are paramount considerations (Mahmoud et al.,

2023).

However, the introduction of blockchain into IoT systems would introduce complexity in the form of high

computational costs, latency, and resource-constricted edge devices. The solution to these limitations is to use

custom architecture that supports the security advantages of blockchain and streamlines towards the

environment of IoT. Recent studies focus on lightweight consensus algorithms and decentralized identity

management, as well as privacy-preserving methods to strike this balance (Almarri and Aljughaiman, 2024).

Specifically, Nwakeze (2024) emphasizes that the cryptographic resiliency of blockchain and the decentralized

nature contribute to the enhancement of security within IoT systems and aid in preventing single points of

failure, as well as contributing to the overall protection of the data within distributed networks.

This paper suggests a new blockchain-based communication model that can be based on all these principles to

secure communication framework of future IoT networks. Under the DSR approach, the study is centered on

the design and development of an artifact, which combines blockchain-based decentralized authentication,

lightweight consensus mechanisms, and smart contract-enabled access control to the secure communication of

the IoT. The implementation in the form of a prototype is carried out on blockchain platforms (Hyperledger)

and the IoT simulation tool (NS-3) to illustrate the operation of the framework. Performance metrics including

latency and throughput, energy consumption and resistance to typical attacks on the IoT are assessed to

demonstrate evidence of the artifact effectiveness and efficiency. The paper focuses on the real-world

construction and experimentation of the framework, and its results are recorded to describe its possible role in

ensuring the security of IoT network architectures.

Figure 1: Architecture of the Proposed Framework

Figure 1 architecture is organized into four layers that are each very important in the achievement of secure,

efficient and scalable data exchange in an IoT ecosystem. The Application Layer is positioned on the top of the

stack and it provides the interface to both the end-users and administrators. This layer will perform the system

monitoring and data visualization and real-time control. It does also deal with the retrieval of the verification

results and audit trail which guarantees transparency and accountability in the activities of the systems. The

result of this layer is fed to administrative decisions and gives information on the performance of the system.

The next layer is called the Blockchain Layer that is used as the base in secure management of data. Some of

the components of this layer include the immutable ledger, smart contracts, lightweight consensus mechanisms

offloading the centralized systems of computing power, allowing the provision of real-time responsiveness to

distributed environments (Suresh Babu et al., 2023; El Kafhali et al., 2019). The base of the architecture is the

IoT Device Layer that consists of the resource-constrained devices in the field. These devices have secure

ownership identities, unique cryptographic identifiers, as well as lightweight capabilities of encryption.

Although they do not have much computational capabilities, they are essential to the gathering of information

and the initiation of secure transactions. The layer enables the interchange of multiple types of identity and

data, such as resource-constrained identity data, cryptographic identity verification, and lightweight data

transmission, which are critical to the provision of security and interoperability in blockchain-based IoT

systems.

blockchains, the real-time functionality of the IoT and edge computing. This two-way flow of data and

layer takes the task of ensuring that IoT interactions are verifiable and not tampered with by ensuring that an

immutable registry of all important communications events, device registrations, and transaction metadata is

kept.

Figure 2: The Blockchain Layer for Decentralized Trust and Automated Policy on IoT

The Blockchain Layer shown in Figure 2 is the fundamental element in the secure, decentralized and auditable

communication in the IoT networks. It is based on an immutable decentralized ledger that stores IoT

transactions, device registration, and data exchange and removes single points of failure, improving the

transparency and traceability of distributed devices (Elgountery et al., 2023). Lightweight consensus primed to

IoT conditions are also used to maintain efficient validation of transactions without straining the resource-

authenticates the identity of devices, and provides resilient, trace-able, and secure interactions between the

heterogeneous IoT environments.

The Edge/Fog Layer is an intermediate between the IoT devices and limited by resources, and the blockchain

network, which offers processing, storage, and security services to the data source. Its main role is to offload

computationally expensive functions on the IoT system, including cryptographic calculations, transaction

authentication, and smart contract execution as illustrated in Figure 3, which will decrease the latency and save

the energy of the devices. By performing local data aggregation, preprocessing, and filtering, this layer

minimizes the volume of raw data transmitted to the blockchain, enhancing both system efficiency and

scalability (Rahman et al., 2023).

Figure 3: The Edge/Fog layer for Intelligent Intermediary for Secure IoT Communication

Every device is given a particular cryptographic identity, which allows registering and authenticating a device

The proposed secure communication framework based on blockchain was introduced as a prototype to test its

functionality, performance, and its viability in the IoT networks. The blockchain platform consisted of

Hyperledger Fabric because of its permissioned network features and support of smart contracts and externally,

NS-3 used to simulate IoT devices, network traffic, and communications protocols. IoT devices received

distinctive cryptographic identities and encrypted data transmission to the Edges/Fog Layer was lightweight in

order to ensure security. On that level, local aggregation, pre-processing, and security policy enforcement were

supported. The Code and use of smart contract verification and the execution of payments were the most

The Blockchain Layer was a decentralized registry where cryptographic hashes of the transactions were stored

evident upward trend of all important metrics. The latency decreased gradually with each epoch (145ms during

Figure 7: System Performance and Transmission Log

The dashboard of the blockchain IoT security system in Figure 7 gives a real-time overview of the

performance and activity of the system, which is essential in assessing the efficiency and robustness of safe

IoT systems. The most important measurements are latency (120ms), throughput (90 transactions per second),

energy consumption (0.95W), and smart contract execution time (30ms), which provide an idea about the

responsiveness of the system and its utilization. The stability and reliability of the blockchain layer can be seen

in the transaction log which indicates the regular processing of 90 transactions in different epochs. Further, the

active nature of a recently added sensor emphasises the dynamic nature of the system to integrate and monitor

IoT devices without any obstacle. Combined, these aspects prove a highly coordinated system that is balanced

to security, scalability, as well as transparency of its operations.