Security and the recovery key
Everything is encrypted on your Mac with a key only you hold. What the recovery key is, where to keep it, and what happens if it is lost.
Encrypted before it leaves
Every file, every file name, every preview and the index Yester uses to browse your backup is encrypted on your Mac before anything is uploaded. Each Mac has its own data key. That key is wrapped with a key derived from your recovery key, and only the wrapped form ever leaves your Mac.
Yester’s servers store ciphertext plus the small amount of plain information needed to bill and tidy up: how big a piece is, when it was written, and how long it must be kept. They never hold a key, and they never see a file name.
Nobody at Yester can read your files
Because Yester never has the key, nobody at Yester can open your backup — not support, not an engineer, not under pressure. The same is true for anyone who might get hold of the stored data. This is deliberate, and it has one consequence that matters.
Yester cannot recover your data without your recovery key
The recovery key is the only way to unlock a backup on a different Mac, or on this Mac after it has been wiped. Yester shows it once, when you set up each Mac. Keep it somewhere you’ll still have if the Mac is gone:
- your password manager,
- printed, in a safe place,
- a copy in your iCloud Keychain (Yester offers this at setup and in Settings → Recovery Key).
There is one recovery key per Mac; it covers every user account on that Mac. You can view it again in the app under Settings → Recovery Key, as long as you’re signed in on that Mac.
If the key is lost
If the Mac is still working and you’re signed in, open Settings → Recovery Key and save it now. If the Mac is gone and the key is nowhere — not in a password manager, not printed, not in iCloud Keychain — the backup cannot be opened, by you or by anyone else. Yester has nothing to reset. Set the Mac up fresh and start a new backup.
Sign-in and devices
Your account is protected by Sign in with Apple or by email codes; there is no Yester password to phish. Each Mac holds short-lived credentials that let it add to its own backup and read from it, and nothing else — no deleting, no reaching other devices. Changing your account password on one device signs the others out; they catch up by themselves once you sign in again.
What Yester sends home
Aggregate, anonymous usage counts — how many backups succeeded, how long restores took — so we can see whether Yester is working. Never file names, never contents, never paths. You can switch it off in Settings. See the privacy policy.