Chrome support for passkeys in iCloud Keychain (18 Oct 2023)
Chrome 118 (which is rolling out to the Stable channel now) contains support for creating and accessing passkeys in iCloud Keychain.
Firstly, I’d like to thank Apple for creating an API for this that browsers can use: it’s a bunch of work, and they didn’t have to. Chrome has long had support for creating WebAuthn credentials on macOS that were protected by the macOS Keychain and stored in the local Chrome profile. If you’ve used WebAuthn in Chrome and it asked you for Touch ID (or your unlock password) then it was this. It has worked great for a long time.
But passkeys are supposed to be durable, and something that’s forever trapped in a local profile on disk is not durable. Also, if you’re a macOS + iOS user then it’s very convenient to have passkeys sync between your different devices, but Google Password Manager doesn’t cover passkeys on those platforms yet. (We’re working on it.)
So having iCloud Keychain support is hopefully useful for a number of people. With Chrome 118 you’ll see an “iCloud Keychain” option appear in Chrome’s WebAuthn UI if you’re running macOS 13.5 or later:
You won’t, at first, see iCloud Keychain credentials appear in autofill. That’s because you need to grant Chrome permission to access the metadata of iCloud Keychain passkeys before it can display them. So the first time you select iCloud Keychain as an option, you’ll see this:
If you accept, then iCloud Keychain credentials will appear in autofill, and in Chrome’s account picker when you click a button to use passkeys. If you decline, then you won’t be asked again. You can still use iCloud Keychain, but you’ll have to go though some extra clicks every time.
You can change your mind in System Settings → Passkeys Access for Web Browsers, or you can run tccutil reset WebBrowserPublicKeyCredential from a terminal to reset that permission system wide. (Restart Chrome after doing either of those things.)
Saving a passkey in iCloud Keychain requires having an iCloud account and having iCloud Keychain sync enabled. If you’re missing either of those, the iCloud Keychain passkey UI will prompt you to enable them to continue. It’s not possible for a regular process on macOS to tell whether iCloud Keychain syncing is enabled, at least not without gross tricks that we’re not going to try. The closest that we can cleanly detect is whether iCloud Drive is enabled. If it is, Chrome will trigger iCloud Keychain for passkey creation by default when a site requests a “platform” credential in the hope that iCloud Keychain sync is also enabled. (Chrome will default to iCloud Keychain for passkey creations on accounts.google.com whatever the status of iCloud Drive, however—there are complexities to also being a password manager.)
If you opt into statistics collection in Chrome, thank you, and we’ll be watching those numbers to see how successful people are being in aggregate with this. If the numbers look reasonable, we may try making iCloud Keychain the default for more groups of users.
If you don’t want creation to default to iCloud Keychain, there’s a control in chrome://password-manager/settings:
I’ve described above how things are a little complex, but the setting is just a boolean. So, if you’ve never changed it, it reflects an approximation of what Chrome is doing. But if you set it, then every case will respect that. The enterprise policy CreatePasskeysInICloudKeychain controls the same setting if you need to control this fleet-wide.
With macOS 14, other password managers are able to provide passkeys into the system on macOS and iOS. This iCloud Keychain integration was written prior to Chromium building with the macOS 14 SDK so, if you happen to install such a password manager on macOS 14, its passkeys will be labeled as “iCloud Keychain” in Chrome until we can do another update. Sorry.