You can now use an Android phone as a physical security key for two-factor authentication on iOS
Google is expanding the ability to use an Android phone as a physical two-factor authentication security key to include iOS devices (the feature previously launched in April, but only worked with Chrome OS, macOS, or Windows 10), as noted by 9to5Mac.
Due to limitations on how iOS works, the process is slightly different here: instead of using Chrome to communicate with the device (as used for the PC versions), the Android phone links up with Google’s Smart Lock app instead.
The net result is that once it’s all set up, when you log into your Google account on an iOS device, the app is able to ping the Android phone over Bluetooth. Then, users can confirm that they are, in fact, the one trying to log in on the Android…