Password AutoFill security
Password AutoFill automatically fills credentials stored in the keychain. The iCloud Keychain password manager and Password AutoFill provide the following features:
Filling in credentials in apps and websites
Generating strong passwords
Saving passwords in both apps and websites in Safari
Sharing passwords securely to a users’ contacts
Providing passwords to a nearby Apple TV that’s requesting credentials
Generating and saving passwords within apps, as well as providing passwords to Apple TV, are available only in iOS and iPadOS.
Password AutoFill in apps
iOS and iPadOS allow users to input saved usernames and passwords into credential-related fields in apps, similarly to the way Password AutoFill works in Safari. In iOS and iPadOS, users tap a key affordance in the software keyboard’s QuickType bar. In macOS, for apps built with Mac Catalyst, a Passwords drop-down menu appears below credential-related fields.
When an app is strongly associated with a website that uses the same app-website association mechanism and that’s powered by the same apple-app-site-association file, the iOS and iPadOS QuickType bar and macOS drop-down menu directly suggest credentials for the app, if any are saved to the Password AutoFill Keychain. This allows users to choose to disclose Safari-saved credentials to apps with the same security properties, without those apps having to adopt an API.
Password AutoFill exposes no credential information to an app until a user consents to release a credential to the app. The credential lists are drawn from or presented out of the app’s process.
When an app and website have a trusted relationship and a user submits credentials within an app, iOS and iPadOS may prompt the user to save those credentials to the Password AutoFill keychain for later use.