Re:Easy Automated Snapshot-Style Backups with Linux and Rsync
by hga on Thursday March 25, 2010 @12:45PM
(#1218795)
But this is not trying to address a duplication problem as far as I can see (see below):
E.g. let's say I have the following blocks of data:
A B C D E F...
And I then change C to C', now having:
A B C' D E F...
With the rsynccrypto approach the ciphertext of D E and F... will be unchanged, allowing rsync to do the right thing (not retransmit everything after C').
Yeah, this leaks info, but it's a compromise between a making the result easier to break and conserving transmission costs (which is very much an issue for me, being stuck behind a slow upstream residential ADSL link).
My question, which I have most definately not answered to my complete satisfaction, is "has the cryptosystem been compromised to the point I might as well have not bothered?"
Just how easy will the know leaks make a attack feasible? How expensive would be such an attack be? I.e. I'm not concerned about the NSA, a lesser degree of security is OK.
As for deduplication, I don't see how it can help; could you be more specific?
(And thanks a lot for taking this issue seriously, it is something I'm concerned about and don't have a sufficient background to be all that confident about my judgment.)
E.g. let's say I have the following blocks of data:
A B C D E F...
And I then change C to C', now having:
A B C' D E F...
With the rsynccrypto approach the ciphertext of D E and F... will be unchanged, allowing rsync to do the right thing (not retransmit everything after C').
Yeah, this leaks info, but it's a compromise between a making the result easier to break and conserving transmission costs (which is very much an issue for me, being stuck behind a slow upstream residential ADSL link).
My question, which I have most definately not answered to my complete satisfaction, is "has the cryptosystem been compromised to the point I might as well have not bothered?"
Just how easy will the know leaks make a attack feasible? How expensive would be such an attack be? I.e. I'm not concerned about the NSA, a lesser degree of security is OK.
As for deduplication, I don't see how it can help; could you be more specific?
(And thanks a lot for taking this issue seriously, it is something I'm concerned about and don't have a sufficient background to be all that confident about my judgment.)