HAIL: A High-Availability and Integrity Layer for Cloud Storage

We introduce HAIL (High-Availability and Integrity Layer), a distributed cryptographic system that allows a set of servers to prove to a client that a stored file is intact and retrievable. HAIL strengthens. formally unifies, and streamlines distinct approaches from the cryptographic and distributed-systems communities. Proofs in HAIL are efficiently computable by servers and highly compact typically tens or hundreds of bytes. irrespective of file size HAIL cryptographically verifies and reactively reallocates file shares It is robust against an active, mobile adversary. i.e. one that may progressively corrupt the full set of servers We propose a strong, formal adversarial model for HAIL, and rigorous analysis and parameter choices. We show how HAIL improves on the security and efficiency of existing tools. like Proofs of Retrievability (PORs) deployed on individual servers We also report on a prototype implementation.