How to ensure the keys are NOT shared on iCloud?

[houmie]

For the lack of a better idea, I'm using the keychain to store device specific information (username/password). It would become very messy if the information is shared across iCloud to other devices that the user may hold. Hence I would like to prevent that and keep the keychain entries per device.

It is very difficult to test this with sandbox user, I hope you don't mind me asking here:

let keychain = Keychain(service: "com.example.github-token").synchronizable(false)
keychain["username"] = "U123"

If .synchronizable is set to false, I can be rest assured that the key/value won't be synced to the user's iCloud and is kept local?

Many Thanks, Houman

[kishikawakatsumi]

Yes, it does. .synchronizable == false means it doesn't sync to iCloud backup.

https://developer.apple.com/documentation/security/ksecattrsynchronizable

Also, set the .accesible parameter to some kind of ...ThisDeviceOnly. It will prevent the keychain items from being restored from iTunes local backup to another device.

[houmie]

Thank you. That was very helpful.