1. SignIn to your IOS Account and go to Settings
2. Connect your U2F key to PC USB port and click to Register
![Image](https://cdn.infinity-box.com/ios/u2f/1.png)
3. Touch a button and your U2F key to confirm token registration
![Image](https://cdn.infinity-box.com/ios/u2f/2.png)
4. Token is registered
![Image](https://cdn.infinity-box.com/ios/u2f/3.png)
5. Select "U2F Key" and click to "Set" to apply changes
![Image](https://cdn.infinity-box.com/ios/u2f/4.png)
At next SignIn you should have U2F key conected
NOTE: You can use the same U2F key for many sites, f.e. for Google, Facebook etc.