Bifrost: Secure, Scalable and Efficient File Sharing System Using Dual Deduplication

Authors: H.Sehat, E.Pagnin, D. Lucani
In: IEEE International Conference on Cloud Networking, 2022
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We consider the problem of sharing sensitive files across users while relying on a common, untrusted third-party, e.g., a Cloud Storage Provider (CSP). Although users can rely on a secure peer-to-peer (P2P) channel for file sharing, this introduces potential delay on the data transfer and requires the sender to remain connected while the transfer process occurs. Instead, users can upload information about the file on a common CSP and share only the essential information that enables the receiver to recover the original file. However, using encryption to protect the uploaded information from the untrusted cloud hinders deduplication capabilities, which is undesirable for CSPs. This paper introduces Bifrost, an innovative file sharing method inspired by recent results on dual deduplication. Bifrost achieves secure file sharing using an untrusted cloud, and simultaneously guarantees that (1) the CSP can efficiently deduplicate outsourced data; (2) the secure P2P channel is used only to transmit short, but crucial information; (3) users can check for data integrity, i.e., detect if the CSP alters the outsourced data; and (4) only the sender and the intended receiver can recover the sensitive file, i.e., the cloud or no malicious adversary can infer useful information about the shared file. We analyze compression and bandwidth performance using a proof-of-concept implementation. Our experiments show that secure file sharing can be achieved by sending as little as 640 bits on the P2P channel, irrespective of file size, while the CSP that aids the sharing can enjoy a deduplication rate of 86.9%.

Keywords: Compression, Privacy, Deduplication, File Sharing