Copying login keychains between Macs fails on Secure Enclave Macs with Tahoe

(derflounder.wordpress.com)

45 points | by zdw 19 hours ago

8 comments

  • xmddmx 35 minutes ago
    Disturbing if true, as it suggests my "everything" backups aren't really full backups at all.

    I wonder, if you have enabled iCloud keychain, does that provide another way to get your passwords back?

    Suppose my MacBook is stolen, but I still have my iPhone. Could I use the passwords app on the iPhone to retrieve my passwords. Would that include all of them or only a subset?

    • lapcat 13 minutes ago
      The iCloud keychain is separate from the login keychain. The Passwords app doesn't use the login keychain.
  • shenenee 2 hours ago
    This is pretty much how it's suppose to work...
    • winstonwinston 2 hours ago
      Maybe but this is unexpected if you need to restore from a backup..
      • ryandrake 1 hour ago
        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.
        • GeekyBear 43 minutes ago
          > As a general principle, as a user, I expect a file on one computer to be usable on another computer.

          As a general rule, I expect a file on an encrypted disk to be unreadable for anyone who lacks the encryption key(s).

          > if I need to obtain some other thing from the original computer to "unlock" that file, I should be able to do it.

          You can export your passwords to a plain text CSV from the original computer.

          • shaky-carrousel 37 minutes ago
            As a general rule, I expect a file on an encrypted disk to be encrypted with a key derived from a password I provide.
          • josephcsible 18 minutes ago
            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.
          • ftchd 36 minutes ago
            As a general rule, if I'm the user of both disks I expect to have the encryption key(s).
      • petronic 1 hour ago
        I've done Tahoe-to-Tahoe migration assistant moves between machines in recent months. No issues with login keychain migration.
        • winstonwinston 1 hour ago
          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.
        • lapcat 1 hour ago
          Migration Assistant uses the old Mac, which can unlock its login keychain and allow the keychain items to be copied.
          • pmontra 13 minutes ago
            What if the old Mac is dead, stolen, lost? Those are the scenarios in which one recovers on a new machine from a backup.
            • lapcat 4 minutes ago
              Then you're in trouble.
      • __MatrixMan__ 1 hour ago
        Don't backup keys, rotate them.
        • gavinsyancey 1 hour ago
          I can't rotate my keys if I lose access to accounts because my computer died and my backup is useless.
          • __MatrixMan__ 1 hour ago
            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

            • pmontra 6 minutes ago
              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.

    • Retr0id 2 hours ago
      I'm more interested by the fact that it apparently didn't work this way before Tahoe.
      • pram 2 hours ago
        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.
        • what 1 hour ago
          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.
    • lapcat 1 hour ago
      > This is pretty much how it's suppose to work...

      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.

  • dfabulich 1 hour ago
    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?
    • lapcat 1 hour ago
      Does the macoOS login keychain get backed up by Time Machine backups

      Yes

      > in a way that could restore the keychain if the original machine's Secure Enclave is lost or destroyed?

      Apparently not

      • dfabulich 28 minutes ago
        "Apparently"? Is this something that can be tested with VMs?
        • lapcat 12 minutes ago
          I've tested with VMs. However, I'm unclear about the relationship if any between VMs and the secure enclave.
  • tencentshill 21 minutes ago
    It's always a good idea to plan to hang on to your old machine for a few weeks to ensure everything works properly on the new one. Apple makes that much easier to forget.
  • lapcat 10 minutes ago
    This was introduced, unannounced, in macOS 26.4! See my blog post for more information: https://lapcatsoftware.com/articles/2026/9/4.html
  • flyingshelf 1 hour ago
    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.
    • ImPostingOnHN 1 hour ago
      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.

  • cute_boi 1 hour ago
    This is good.