Tahoe-LAFS

Tahoe-LAFS (Tahoe Least-Authority File Store) is a free and open, secure, decentralized, fault-tolerant, distributed data store and distributed file system. It can be used as an online backup system, or to serve as a file or Web host similar to Freenet, depending on the front-end used to insert and access files in the Tahoe system. Tahoe can also be used in a RAID-like fashion using multiple disks to make a single large Redundant Array of Inexpensive Nodes (RAIN) pool of reliable data storage.

The system is designed and implemented around the "principle of least authority" (POLA), described by Brian Warner (one of the project's original founders) as the idea "that any component of the system should have as little power of authority as it needs to get its job done". Strict adherence to this convention is enabled by the use of cryptographic capabilities that provide the minimum set of privileges necessary to perform a given task by asking agents. A RAIN array acts as a storage volume; these servers do not need to be trusted by confidentiality or integrity of the stored data.