Is it possible to detect if an Apple Watch has a passcode set?

Question

Created Apr ’21

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I need to know if an Apple Watch user has a passcode set before we can show sensitive data in a View.

Is there a way to check for this?

LAPolicy is unavailable on the Watch and I cannot check deviceOwnerAuthenticationWithWatch from a paired phone only from a Mac.

Answered by pawpoise in 671815022

Eskimo, thank you so much for the suggestion. With that I think I'm now on the right track.

I have the following options set when adding the item to the keychain:

Code Block  swift        let flag = SecAccessControlCreateFlags.userPresence
        let sacResult = SecAccessControlCreateWithFlags(kCFAllocatorDefault, 
                        kSecAttrAccessibleWhenPasscodeSetThisDeviceOnly, flag, &error)

and have

Code Block  swift            kSecUseAuthenticationUI as String: kSecUseAuthenticationUIFail

in the attributes for SecItemCopyMatching

On my own watch with passcode on I get the "User interaction is not allowed" error, which seems correct.
I didn't see that in the simulator where the passcode cannot be set - that shows "No error."

I need to verify with passcode off on a device but this looks really promising. Thank you

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Answer 1

DTS Engineer OP

Apple

Apr ’21

I don’t have time to try this today but I figured I’d pass it along just in case it works (-:

I need to know if an Apple Watch user has a passcode set before we can
show sensitive data in a View.

If you gate access to your view via a keychain item that’s protected with kSecAttrAccessibleWhenPasscodeSetThisDeviceOnly, does that do what you want? Ideally the sensitive data should be encrypted with the content of that keychain item but for a quick test you can just see whether the item is available.

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—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

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Answer 2

pawpoise OP

Apr ’21

Accepted Answer

Eskimo, thank you so much for the suggestion. With that I think I'm now on the right track.

I have the following options set when adding the item to the keychain:

Code Block  swift        let flag = SecAccessControlCreateFlags.userPresence
        let sacResult = SecAccessControlCreateWithFlags(kCFAllocatorDefault, 
                        kSecAttrAccessibleWhenPasscodeSetThisDeviceOnly, flag, &error)

and have

Code Block  swift            kSecUseAuthenticationUI as String: kSecUseAuthenticationUIFail

in the attributes for SecItemCopyMatching

On my own watch with passcode on I get the "User interaction is not allowed" error, which seems correct.
I didn't see that in the simulator where the passcode cannot be set - that shows "No error."

I need to verify with passcode off on a device but this looks really promising. Thank you

0