Wikipedia
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 manner to use multiple disks to make a single large RAIN pool of reliable data storage.
The system is designed and implemented around the " principle of least authority" (POLA). Strict adherence to this convention is enabled by the use of cryptographic capabilities which grant the minimal set of privileges necessary to accomplish a given task to requesting agents. A RAIN array acts as storage — these servers do not need to be trusted for confidentiality or integrity of the stored data.
Zooko Wilcox-O'Hearn is one of the developers.