pStore: A secure peer-to-peer backup system

In an effort to combine research in peer-to-peer systems with techniques for incremental backup systems, we propose pStore: a secure distributed backup system based on an adaptive peer-to-peer network. pStore exploits unused personal hard drive space attached to the Internet to provide the distributed redundancy needed for reliable and ef-fective data backup. Experiments on a 30 node network show that 95 % of the files in a 13 MB dataset can be retrieved even when 7 of the nodes have failed. On top of this reliability, pStore in-cludes support for file encryption, versioning, and secure sharing. Its custom versioning system per-mits arbitrary version retrieval similar to CVS. pStore provides this functionality at less than 10% of the network bandwidth and requires 85 % less storage capacity than simpler local tape backup schemes for a representative workload.