privateshared

PrivateShared is a privacy-focused framework and platform designed for private data sharing and collaboration. It provides end-to-end encryption, client-side key management, and granular access control for files, messages, and collaborative documents. The design emphasizes minimizing server-side metadata and enabling revocation and time-limited access without exposing content.

The architecture relies on client-side encryption with per-user asymmetric keys and optional symmetric session keys. Data can be stored on decentralized or centralized storage backends, with content-addressable storage and cryptographic tokens to authorize access. Access control is implemented through per-share policies, allowing revocation, expiration, and conditional access. The system supports multi-party access through threshold cryptography and favors architectures that keep most cryptographic operations on the client. An open-source reference implementation provides cross-platform clients for desktop and mobile.

History and reception: PrivateShared was conceived by a consortium of privacy researchers and engineers in the early 2020s and released in stable form in 2023. Subsequent updates expanded support to documents, chat, and collaboration features, while improving metadata minimization and audit capabilities. It has seen adoption among privacy-focused organizations, academic researchers, and communities experimenting with privacy-preserving sharing models.

Limitations and governance: While prioritizing privacy, PrivateShared introduces complexity in key management and trust assumptions. Performance can be affected by cryptographic overhead, particularly on lower-end devices or networks. Interoperability and standardization are ongoing topics, with discussions about broader compatibility with other privacy tools and regulatory compliance.