Note: Transparent data deduplication in the cloud

What

Design and implement ClearBox which allows a storage service provider to transparently attest to its customers the deduplication patterns of the (encrypted) data that it is storing.

Why

Storage saving has not directly benefit to users as there is no transparent relation between effective storage costs and the prices offered to the users.

How

• System security: Put/Get/Attest/Delete/Verify Protocol.
• Cryptographic accumulators （one-way membership functions）answer a query whether a given candidate belongs to a set.
• Time-Dependent Randomness.
• Server-Aided Key Generation: Blind BLS signature.
• Proofs of Ownership: Halevi's work.

Some Details

Blind BLS Signature

• Using PBC Library
• Using random g1 and r for generate blind number k, \(k=g1^r\).
• Blind by h * k, where h is the origin hash of a chunk.
• Unblind by sig / k, where sig is the blind BLS signature of blind hash (h * k).