International Journal of Science, Engineering and TechnologyAuthors: Dr. D. Prabhu, Nithishwaran A, Someshwaran C, Sasikumar K, Sachin S
Abstract: Modern cloud storage platforms raise serious concerns about data privacy, since most service providers retain access to user encryption keys. This paper presents Nimbus Cloud, a client-side encrypted storage system built on a zero-knowledge architecture in which the server stores only ciphertext and has no knowledge of plaintext data or encryption keys. All cryptographic operations—including AES-256-GCM encryption and RSA-based key exchange— execute entirely within the user's browser before any data leaves the device. The system supports single-user and group based file sharing through Public Key Encryption (PKE) and an RSA-wrapped AES group-key scheme. The implementation employs React.js on the frontend, Node.js with Express on the backend, MongoDB for metadata management, and Cloudinary (backed by Amazon AWS) for encrypted file storage. Structured testing across eight functional scenarios—spanning authentication, encryption, upload, download, sharing, and access control—confirmed complete correctness and validated the zero-knowledge property under every evaluated condition.
DOI: http://doi.org/10.5281/zenodo.20201705
