Two-step verification can help thwart malicious attacks against your online accounts. Anyone trying to break into your account would need both your password and the mobile device that authentication codes are sent to in order to gain access.
Google has done a splendid job of providing options for those who are interested in setting up this extra security measure: you can get text alerts, or you can use Google's authenticator app, available for Android, BlackBerry, and iOS.
When using the app as your method of authentication code delivery, you may wonder what happens when you want to retire an old phone for a new one. Or, you may have misplaced your device and want to disable the service as a precautionary measure. Here's how to move the authenticator app to a new device, or disable it completely:
Step 1: First you'll want to install the app on the new device where you want to receive authentication codes.
Step 2: Next, head to Google's two-step verification Web page using a browser on your computer. You may need to log in to your Google account to access the security settings.
Step 3: Click the link that says "Move to a different phone." If you're disabling the feature completely, you can just click "Remove."
Fortunately, moving your authenticator to a new device will not invalidate any of your existing application-specific passwords, and does not require any backup codes to complete the transition.
Step 4: Scan the QR code that appears, or enter it manually by clicking, "Can't scan the bar code?"
Step 5: Finally, enter the authentication code that appears on the screen to verify the device. This is just like the log-in process when using two-step verification.
Before removing the authenticator from your original device, remember to move your other accounts that are using the app. You'll need to visit each site individually and scan the QR code with your new device.
Editors' note, February 19, 2015: This How To post was originally published on June 28, 2013, and has been updated to include new information.