Hacker News new | ask | show | jobs
by chimeracoder 282 days ago
> I do that and then sync that folder with another computer using SyncThing.

AFAIK SyncThing only monitors for changes between files with matching names, and Signal stores each backup with a separate (timestamped) filename. Are you storing every day's backup individually, or do you have some tool for deduplicating?
1 comments
hiq 282 days ago
Encrypted backups can't be deduplicated unless the encryption is flawed. There shouldn't be a way to tell that one Signal backup is somewhat related to another, unless you have the passphrase.

That also means that Syncthing can't do better than sending the full backup. But if you're syncing via wifi (e.g. at home) it's not really a problem anyway.

link
codethief 282 days ago
> Encrypted backups can't be deduplicated unless the encryption is flawed.

Would you mind elaborating on why this would be an issue? 1) Tools like borgbackup provide the exact functionality you're describing and considered secure. 2) Encrypted file systems also don't re-encrypt your entire HDD whenever you change a single file.

link
chimeracoder 282 days ago
> Encrypted backups can't be deduplicated unless the encryption is flawed

This isn't an encryption problem; each device can only have one instance of Signal installed, and the latest backup (assuming it has terminated successfully) is a superset of the previous ones (aside from any messages that have dropped from retention, which you presumably don't want to be preserving, by definition).

"Deduplicate" in this context means ensuring that you only have N backups in your remote storage, rather than cumulatively storing every day.

link
hiq 282 days ago
Signal has always between one and two backups, it removes the old ones.
link