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.
I think it's time to update your expectations. Hardware security modules have been around for quite a while. You shouldn't assume that your chosen password is the only input to the key derivation, or even that the raw key itself will always be obtainable.
I never assumed that my chosen password was the only input to the key derivation. Just that my chosen password is at least one of the inputs to the key derivation. LUKS has been around for quite a while.
It's also unexpected when you send your laptop in for a screen replacement, the tech does an unnecessary logic board swap while he's at it, and your local keychain doesn't work anymore. And then Apple Support will say, hey, we told you you needed to backup your data! Which you did, but that's not the issue.
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.
What information from your login keychain do you expect to need on your new computer?
There's not really a plausible answer to that question, because the login keychain data is almost entirely specific to that host.
To iron-man your argument: Apps that store account credentials to third party services will need to be signed in again.
If you were using http basic auth for a website and saving that, then it was probably in there.
Private keys and certificates you manually imported, or that were created by an application for your host. This is the closest to a plausible answer, imo.
Can you clone or sync hardware keys? Maybe they don't fail as much as computers do but they can be lost or stolen like the keys that we use to open (dumb) doors.
My non hardware key is a keypass file that I update only on my laptop and I sync to my other devices. I have plenty of backups. It does also the TOTP required to login into some customers servers.
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Maybe but this is unexpected if you need to restore from a backup..
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.
As a general rule, I expect a file on an encrypted disk to be unreadable for anyone who lacks the encryption key(s).
You can export your passwords to a plain text CSV from the original computer.
As a general rule, I expect a file on an encrypted disk to be encrypted with a key derived from a password I provide.
I think it's time to update your expectations. Hardware security modules have been around for quite a while. You shouldn't assume that your chosen password is the only input to the key derivation, or even that the raw key itself will always be obtainable.
I never assumed that my chosen password was the only input to the key derivation. Just that my chosen password is at least one of the inputs to the key derivation. LUKS has been around for quite a while.
You're asking for the encryption key to be derivable by an unrelated system that only has the encrypted file and your password.
As a general rule, if I'm the user of both disks I expect to have the encryption key(s).
The right way to do that is FDE, where you can't even mount the filesystem to see the files without having the decryption key.
It's also unexpected when you send your laptop in for a screen replacement, the tech does an unnecessary logic board swap while he's at it, and your local keychain doesn't work anymore. And then Apple Support will say, hey, we told you you needed to backup your data! Which you did, but that's not the issue.
Use iCloud Keychain or don't use Keychain at all.
I've done Tahoe-to-Tahoe migration assistant moves between machines in recent months. No issues with login keychain migration.
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.
Migration Assistant uses the old Mac, which can unlock its login keychain and allow the keychain items to be copied.
What if the old Mac is dead, stolen, lost? Those are the scenarios in which one recovers on a new machine from a backup.
What information from your login keychain do you expect to need on your new computer?
There's not really a plausible answer to that question, because the login keychain data is almost entirely specific to that host.
To iron-man your argument: Apps that store account credentials to third party services will need to be signed in again.
If you were using http basic auth for a website and saving that, then it was probably in there.
Private keys and certificates you manually imported, or that were created by an application for your host. This is the closest to a plausible answer, imo.
Then you're in trouble.
Migration assistant can also use a TM backup, I’m pretty sure
Don't backup keys, rotate them.
I can't rotate my keys if I lose access to accounts because my computer died and my backup is useless.
Yeah, that's why secure enclaves embedded in complex devices are a bad idea.
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
Can you clone or sync hardware keys? Maybe they don't fail as much as computers do but they can be lost or stolen like the keys that we use to open (dumb) doors.
My non hardware key is a keypass file that I update only on my laptop and I sync to my other devices. I have plenty of backups. It does also the TOTP required to login into some customers servers.