With the rapid rise of cybersecurity threats and the increasing complexity of digital security, event log Data serves as a critical source for identifying and analyzing cyberattacks and threats. This Data provide key insights into system activities, essential for detecting unauthorized intrusions, analyzing suspicious behaviors, and conducting security investigations. However, any alteration or tampering with the Data can disrupt the analysis and detection processes, leading to incorrect security decisions. Blockchain technology, with its unique features such as decentralization, immutability, and transparency, has been recognized as a reliable and secure platform for storing and protecting Data. This technology enables the storage of Data hashes in a way that any changes can be easily detected. However, directly storing the vast volume of event log Data on the blockchain faces challenges such as high costs and storage space limitations. In this research, an innovative model has been presented to automate the assurance of event log Data integrity and confidentiality using the public Ethereum blockchain and smart contracts. Instead of storing event log Data directly, only their hashes have been saved on the blockchain. This approach not only reduces storage costs but also ensures Data confidentiality. The automated Data integrity assurance process in this model occurs in two stages: Stage One: Event log Data hashes have been periodically stored on the blockchain and compared with previous hashes. Stage Two: Over longer intervals, all stored hashes have been reviewed and validated to prevent any potential tampering. In this study, the costs associated with implementing this model on the Ethereum Sepolia test network had been precisely calculated. The analysis indicates that operational costs and computational overhead have been optimized across different time intervals, demonstrating the model's feasibility for large-scale deployment. Ultimately, this research tries to introduce a novel and practical model, taking a significant step toward automating the assurance of event log Data integrity and confidentiality, providing a reliable solution for real-world applications.