Does the macoOS login keychain get backed up by Time Machine backups in a way that could restore the keychain if the original machine's Secure Enclave is lost or destroyed?
It's unexpected to anyone with intuition about how a computer traditionally is supposed to work. As a general principle, as a user, I expect a file on one computer to be usable on another computer. Or, at the very least, if I need to obtain some other thing from the original computer to "unlock" that file, I should be able to do it. The idea of a file that is only usable on a particular computer feels weird.
But that’s not backup restore? I’m thinking Time Machine restore on a new Mac when old one is no longer working. Or when the old one had to be wiped and restored.
IIRC there are options for exportable and un-exportable private keys when you make one in the secure enclave. Going to guess Tahoe made them un-exportable by default.
As far as I know, you have never been able to import or export keys from the Secure Enclave. It’s more likely that previously keys were stored in the keychain and now they are generated in the SE by default.
And yet if you click export it will gladly print out a plaintext csv with your whole life in passwords. Doesn't even attempt to zip it with password or something.
that seems reasonable, as it is the lowest common denominator for interoperability
what would be unfortunate is if it was in some format that couldn't be used by most other systems without extra work, and if the user wasn't able to use their own property to export their own passwords in a different format.
Yes
> in a way that could restore the keychain if the original machine's Secure Enclave is lost or destroyed?
Apparently not
As a general rule, I expect a file on an encrypted disk to be inaccessible to anyone who lacks the encryption key(s).
Hardware keys are the way:
- Less likely to fail in the first place
- Cheap enough to have several of so you can use one to log in and manage the others in the event of loss
- Easy to move between devices
- Less likely to use the auth handshake as a side channel for things you didn't consent to
No, it's not, and that's not how it ever worked in macOS 26.3 and earlier.
This change was introduced in 26.4 for some reason.
what would be unfortunate is if it was in some format that couldn't be used by most other systems without extra work, and if the user wasn't able to use their own property to export their own passwords in a different format.