Cloud Storage and Secure File Sharing Using Blockchain with Xchacha20 and Shake Cryptography

Blockchain technology revolutionized record keeping for secure transactions but is not naturally file storage-oriented. This means that to share files securely and without central control systems, their secured decentralized sharing system needs to be developed. we propose an efficient file-sharing and storage system based on cryptographic hash function SHAKE-256 and end-to-end encryption using XChaCha20. The system highlights emphasis on privacy and integrity of data based on flexible access control policies for authorized users to access specific groups of data. Architecture will eliminate dependence on central storage solutions that are prime to vulnerabilities and single points of failure. Our solution offers a scalable and secure environment for applications in need of decentralized file storage by combining blockchain with more enhanced cryptographic techniques. Experimental results validate that the system is effective in keeping data confidential, integrity, and accessibility so it is eligible for privacy-sensitive use cases.