# Blockchain Based Secure Routing and Trust Management in Wireless Sensor Networks +
## 2 Related Work
### Data Storage
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Problems** & **Already** & **Solutions** & **Already** & **Validations Already Done** & **Problems to be Addressed** & **C1** & **C2** & **C3** \\ \hline Network latency and data delivery issues occurs due to mobile sensors & An intrusion prevention framework is proposed for mobile IoT devices to provide reliable data routing [28] & Network lifetime, Packet Delivery Ratio (PDR), energy consumption, delay and routing overheads & Network lifetime, Packet Delivery Ratio (PDR), energy consumption, delay and routing through them & In XOR hashing function, if an attacker knows one of the plain texts, then get another through them & \(\times\) & ✓ & ✓ \\ \hline Increase network overhead & Trust aware localized routing discovers multiple routes but selects one route with trusted SNs [29] & Security and throughput, encryption and decryption performance, time complexity & No authentication mechanism. Malicious nodes cause low packet delivery and high packet delay & \(\checkmark\) & \(\times\) & \(\times\) \\ \hline Trust issues and single point of failure due to the central authority & BCR protocol is introduced that enables trust relationship between IoT vendors and cooperators [30] & Throughput, PDR, route acquisition latency, routing overhead & Low PDR & \(\times\) & ✓ & \(\times\) \\ \hline Malicious nodes cause gray and black hole attacks & A routing scheme through blockchain and reinforcement learning is used [31] & Enhance the routing efficiency and security of WSNs & Expense and burden increased on the server side due to the operational complexity & \(\checkmark\) & \(\times\) & \(\times\) \\ \hline Storage and bandwidth issues & A light chain system for resource constrained devices is proposed [32] & Hash operations, hash quality, throughput, storage cost & N/A & \(\times\) & \(\times\) & ✓ \\ \hline Distributed nature requires high storage and faster transaction & Multi-level architecture for handling the IoUT data is proposed [33] & Reliability, accuracy, total re-maining energy, energy consumption & N/A & ✓ & \(\times\) & ✓ \\ \hline Local copy of the blockchain records is not feasible & Aggregated information is used to reduce the communication cost [34] & Relative frequency, communication cost & N/A & \(\times\) & \(\times\) & ✓ \\ \hline Blockchain has a slow update rate, while, in Tangle, miners validate its two previous transactions before joining network & The authors presented an optimized policy by using Tangle and blockchain technologies for sampling rate [35] & Age of information and sampling interval & N/A & \(\times\) & \(\times\) & ✓ \\ \hline PoW requires high processing ability and data storage availability & Mobile edge computing framework is proposed to utilize the blockchain [37] & Total net revenue & N/A & \(\checkmark\) & \(\times\) & ✓ \\ \hline Nodes may behave selfishly, they do not forward the packet & An incentive mechanism encourages the nodes to store the data [38] & The proposed system reduced the computing power as compared to the PoW & No authentication mechanism, expensive data storage & ✓ & \(\times\) & ✓ \\ \hline Blockchain requires high resources to perform PoW on mobile devices & Rolling blockchain is proposed where smart cars are used as the nodes of the WSN. The whole database is stored on the server [39] & Probability of finding the connected paths & Merkle tree is not utilized for this network & \(\checkmark\) & \(\times\) & ✓ \\ \hline High latency, scalability issues and single point of failure & Blockchain and SDN based hybrid architecture are used [40] & Hash rate, transactions per second, average time per block and latency & Credential information stored on SDN can be leaked & \(\times\) & \(\times\) & ✓ \\ \hline High computational cost and storage constraint due to a large number of IoT devices & SDN, edge, fog and blockchain are used to develop a secure attack detection system [41] & F1-score, detection time, detection rate, accuracy, bandwidth Matthews correlation coefficient & System complexity increased, requires high computational power, cloud causes high latency & \(\times\) & \(\times\) & ✓ \\ \hline The service provider offers malicious services to the client & A blockchain based fair nonrepudiation service provisioning mechanism is proposed [42] & Average gas consumption, average transaction latency, average throughput & No off-chain mechanism is mentioned to deliver the major service part & \(\times\) & \(\checkmark\) & ✓ \\ \hline \hline \end{tabular}
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