## 2 Related Works
The Honey Encryption (HE) technique is used for encryption. In another study [22], the K-means technique was used for validation. Authentication takes place between cluster leaders and cluster member nodes. In another study [23], a deep learning-based authentication model was proposed. The deep neural network (DNN), the convolutional neural network (CNN), and the convolution preprocessing neural network (CPNN) algorithms are implemented on the nodes. The most effective solution among them has been with CPNN. The model consists of three stages: Initialization, Authentication, Retraining. In another study [24], authentication was performed using the fuzzy technique. Unfortunately, the above studies without blockchain cannot be used in applications that need high security requirements. In terms of the IoT, the concept of things has a very broad meaning. All kinds of monitoring devices, sensors, and access devices are considered as things. For example, when we think in terms of a house, air conditioners, cameras, lamps, TVs, modems, dishwashers, and refrigerators can be considered as things. The IoT, on the other hand, defines the communication network in which physical objects relate to each other or with larger systems. Wireless Sensor Networks are a subset of the IoT. Wireless Sensor Networks are one of the technologies often used in an IoT system [25]. The WSN has sensor nodes with limited capacity. Each sensor node has a limited memory, processor, and power to be cost-effective as their number is huge according to the application. In summary, there is a difference in capacity between IoT and WSN hardware. High-capacity devices can be found in the IoT, while more limited devices are available in WSNs. That is why the IoT-blockchain relationship and the WSNs-blockchain relationship are different. Since blockchain-based WSN studies are not enough, IoT-blockchain studies [6; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35], IoT-blockchain-cloud studies [36], IIoT-blockchain studies [37; 38; 39], and smart system-blockchain studies [40; 41; 42] were researched. It has been seen that the studies are not suitable for WSNs when considered in terms of cost. The communication protocols used in these studies cannot be used directly in sensor nodes due to the required processing and memory capacity. The limited studies involving blockchain-based WSNs are as follows: In the review study [43], studies involving blockchains in WSNs were discussed. The studies are classified as Data Security and Reliability, Data Management and Storage, Node Recovery, Energy Efficiency. These studies [44; 45; 46; 47] include WSN-blockchain and are incomplete and undetailed studies. There is not much to know, such as the type of blockchain implemented, the consensus mechanism, and how smart contracts work. In another study [48], blockchainwas used with AES and the accuracy of the proposed methodology was measured on a temperature-humidity-sensing IoT-based WSN. In another study [49], blockchain technology was implemented in real nodes and the transaction steps were explained in detail. This study was carried out as a basic study at a simple level. The limited number of studies that fully combine blockchain-based WSN technology are as follows: In the study [50], a hybrid model is proposed in the form of a local blockchain with cluster leaders and a public blockchain with base stations. While the public blockchain is used to verify the cluster leaders, the local blockchain is used to verify the cluster member sensor nodes. The authentication model consists of four stages: initialization, registration, authentication, and node logout. In another study [51], a hybrid model is proposed, including an internal blockchain with sensor nodes and a global blockchain with cluster leaders. It consists of four stages, namely Security Parameter Fixing, Blockchain Joining, Authorization, and Sensor Deregistration. Structurally, it is similar to the study numbered [50]. In another study [52], a trust model and blockchain-based authentication are suggested for secure routing.