# Utilizing Blockchain for IoT Privacy through Enhanced ECIES with Secure Hash Function
## 3 Modified ECIES with Secure Hash Function
[14];
* The average computation time for device_Model samples of 250-device group dataset is 98.745 ms, which is less than the recorded value of 105.68 ms for [PERSON] et al. [14];
* The average computation time for device_SN samples of 500-device group dataset. for the proposed solution is equal to 98.615 ms comparing to 103.766 ms for [PERSON] et al. [14]. A comparison between our proposed scheme and [PERSON] et al. [14] is presented in Table 7. Both solutions are based on ECIES that protect the confidentiality and privacy of request transaction messages and response data before data transmission in IoT. While [PERSON] et al. [14] is mutually authenticated with ECIES, our proposed model modified the ECIES with an SHF. Using an SHF to derive private and public keys reduces the correlation coefficient, which improves the security strength of the request transaction data. Our contribution relies on the fact that SHF improves the strength of encryption/decryption of the transmitted message by adding new features for calculating private and public keys

Figure 4: Average Computation Time results for Proposed Scheme and [PERSON] et al. [14]. Figure 3: Average Correlation Coefficient results for Proposed Scheme and [PERSON] et al. [14]. from the safer elliptic curve point, as compared to the case of [PERSON] et al. [14], which does not use hash function generation in the process of calculating the private and public keys. Moreover, in [PERSON] et al. [14], the security strength of the key was compromised, resulting in the violation of user privacy in IoT. However, to enhance the privacy and reliability of the processed user data in IoT, the new features adopted in the proposed scheme greatly enhance user privacy in the IoT system. The use of KDF during the encryption procedure of the request control stage introduces key stretching capability in the proposed scheme, which helps to derive multiple keys from a single master key. This feature decreases the number of iterations while deriving keys for authentication. As a result, the proposed scheme achieves a reduction in encryption and decryption time. The computation time calculated in the proposed scheme eliminates user dependent variables by including time for transaction generation and verification to calculate computation time. This feature ensures the reliability of the proposed scheme with reduced computation time compared to [PERSON] et al. [14] by an average of 7 ms per number of transactions. ## 6 Conclusions and Future Work

Data security and user privacy have been the emerging needs in the IoT system. In this work, we presented a Blockchain-based scheme to preserve user privacy in IoT. The proposed scheme provides a secure platform that allows the access requester to send the request transaction data and receive the response data for the corresponding request. We propose to use ECIES with SHF, which is the new feature adapted from [PERSON] et al. [14], to protect the confidentiality and authenticity of the transmitted request transaction and response data. The use of an SHF to derive private and public keys enhanced user privacy in IoT. This enhancement could improve the security strength of the request transaction data, which helps to derive multiple keys from the single master key; decreasing the number of iterations while deriving keys for authentication and elimination. As a result, it reduces the computation time in the proposed solution by an average of 7 ms per number of transactions compared to the work of [PERSON] et al. [14]. In the future, we need to explore other cryptographic approaches to provide a secure platform for users and data requester to exchange their data in the IoT environment. Future research needs to focus on issues other than protecting the confidentiality and authenticity of the request transaction data and response data to enhance user privacy in IoT, such as investigating and utilizing different techniques to integrate within the blockchain network for achieving enhanced privacy in the IoT system.