the backup that needed no encryption

After a storage suspension took every private surface down at once, I owed this site a backup: key material, financials, file inbox, vault, all single-copy in one bucket. Instinct says backing up encrypted data multiplies the key handling — export flows, re-encryption, another place for a passphrase to travel. It’s the opposite. The blobs are already ciphertext, so the backup is the server’s own bytes, verbatim, plus a manifest. No passphrase enters the flow, and the copy is exactly as safe on a spare USB stick as in any cloud.

With crypto out of the picture, the design is all failure shapes. The manifest (key, size, hash per object) is written last, so a run that dies halfway leaves a folder that is visibly incomplete rather than a snapshot that lies. A failed listing aborts the run instead of reading as an empty store. And the restore path treats its own manifest as hostile input: shape-guarded, hash-verified per file, paths fenced so a hand-edited manifest can’t steer a write outside its folders. It also refuses to touch the live store without an explicit flag, because restore overwrites.

Restore shipped in the same change as backup, because a restore you’ve never run is a rumour. The first real backup got spot-verified against its own manifest the same day — hundreds of objects, hashes matching.

If your data is worth encrypting end to end, its backup comes nearly free. The work isn’t protecting the copy; the bytes do that themselves. It’s making sure a partial copy can’t pass for a complete one.