This could make people think twice about using a phone number to secure their account at all.
Google's Titan Security Keys, used to lock down accounts, are produced in China. Several experts want more answers on that supply chain process, for fears of tampering or security issues.
When a site offers different methods of authentication, your account is only as secure as the weakest option. Here, Motherboard shows you how to use the most robust method for locking down your Twitter account.