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I'm a little concerned about the use of deduplication and encryption in the same system. If done improperly, deduplication followed by encryption potentially l
by jude- 12y ago
I'm a little concerned about the use of deduplication and encryption in the same system. If done improperly, deduplication followed by encryption potentially leaks information--a passive adversary can make some good guesses at what's going in with the plaintext across backups, based on how big or small the size delta is. Maybe I'm being overly paranoid, but I didn't find a satisfactory answer in the documentation at how to plug this side-channel. Would an experienced user or the author be willing to comment?
- mappu 12y agoThe active version of this attack is totally worrying (deduplication between multiple user accounts, alice and eve). But the passive version above requires a privileged network position as well as an unrealistically good idea about what was in the original backup. I agree it's a weakness, but i'm not sure it's a cause for concern You might equally say something like "the amount of time taken to backup is a timing side-channel into the size of the deduplication cache", it's true but i don't think it immediately lead to any practical attacks. Can you elaborate on a scenario?