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You will be presented with two these options:
1) Using a mobile app
2) SMS text messaging
3) Hardware key
The SMS option is perhaps slightly more convenient, however using one of the mobile apps is more secure. We recommend Google Authenticator app, which is available for Android in the Google Play Store and iOS through the iTunes store. The hardware key option uses a physical USB device that needs to be plugged in to the device that you are logging into.
More information can be found on the following documents:
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