# Utilizing Blockchain for IoT Privacy through Enhanced ECIES with Secure Hash Function
## 3 Modified ECIES with Secure Hash Function
[14] and the proposed scheme. The strength of the transmitted message is measured in terms of the correlation coefficient between the constructed request transaction and encrypted request transaction. The performance evaluation of the proposed scheme is based on the comparison of correlation coefficient and computation time with that of [PERSON] et al. [14]. We note that the correlation coefficient measures the closeness between the mapped points on the elliptic curve for the constructed request transaction and encrypted request transaction. The lower the value of the correlation coefficient, the more secure the encrypted transaction. We compared samples taken from our result with the device ID attribute of the 50-device group set from the dataset. This result consisted of the encrypted transaction for request transactions in the request control stage for both [PERSON] et al. [14] and the proposed scheme, where the comparison is based on the correlation coefficient between constructed request transactions and encrypted request transactions. Table 1 includes the device ID attribute of three samples; the constructed request transaction for each device ID and encrypted request transaction in [PERSON] et al. [14] and our proposed scheme. The measured correlation coefficient here improves from 0.3451 to 0.3052 in the first sample of device ID attributes, which clearly demonstrates the improved security strength of the encrypted transaction due to the lower correlation coefficient. Apart from the device ID samples, we tested other attributes of the device information such as device_Type, device_Model, and device_SN attributes. Ten samples were taken from each of the datasets of 50-, 150-, 250-, and 500-device group set. The results are obtained during the request control stages before uploading the request transaction into the smart contract of the blockchain network, and are shown in Tables 2-5, respectively. It is evident from the provided tables that the proposed solution improves the correlation coefficient between the constructed request transaction and encrypted transaction, providing increased security strength of the encrypted transaction. We also calculate the average values of the correlation coefficient and computation time for the proposed scheme and for [PERSON] et al. [14], as shown in \[h(m)=\psi(m)\quad|\quad\psi:\{0,1\}^{*}\rightarrow\{0,1\}^{256},\]1 The result shows a noticeable improvement in both the correlation coefficient and the computation time compared to [PERSON] et al. [14]. Figure 3 shows the average correlation coefficient results for the proposed scheme and for [PERSON] et al. [14], which demonstrates the security strength of the transmitted message. The results for [PERSON] et al. [14] are shown in blue, while the orange color indicates the result for the proposed solution. Every paired blue-orange bar represents the correlation coefficient of the 50-, 150-, 250-, and 500- device group sets with the attributes device_ID, device_Type, device_Model, and device_SN, respectively. The average correlation coefficient for the proposed scheme for device_ID samples of the 50-device group dataset is reduced to 0.30122, whereas it is 0.34499 for [PERSON] et al. [14]. Similarly, the average correlation coefficient for device_Model samples of 250-device group dataset is also reduced to 0.30359, whereas it is 0.34853 for [PERSON] et al. [14]. Finally, the average correlation coefficient for device_SN samples of 500-device group dataset for the proposed solution is reduced to 0.30089 comparing to the record of 0.34433 for [PERSON] et al. [14]. We attribute the degree of improvement in the correlation coefficient to the modified private and public keys for encryption in the proposed scheme. The proposed scheme improves the correlation coefficient from 0.04344 to 0.04377 between constructed request transactions and encrypted request transaction, which shows increased security strength of the transmitted message.