Data storage has been transformed by cloud computing, which offers scalable, flexible, and affordable services. Centralized cloud architectures are still susceptible to insider threats, data manipulation, integrity breaches, and a lack of transparency, though. In cloud systems, ensuring data integrity and trust has emerged as a significant research topic. In order to provide a decentralized and impenetrable verification method, this study suggests a Blockchain-Based Secure Data Storage Framework that combines blockchain technology with cloud computing.

The Advanced Encryption Standard (AES) is used in the suggested method to encrypt files prior to cloud storage. Smart contracts are used to create and store a SHA-256 cryptographic hash of the encrypted file on the blockchain.

The hybrid design uses blockchain's immutability for secure integrity verification while ensuring scalability using off-chain cloud storage. In order to identify any unauthorized changes, the system recalculates the file hash during data retrieval and compares it with the blockchain record. The suggested approach guarantees safe data verification in cloud contexts, increases transparency, strengthens auditability, and does away with centralized trust dependency.In comparison to conventional cloud storage systems, experimental study shows enhanced security and dependable tamper detection