Google will now accept your iPhone as an authentication key
Smart Lock for iOS uses the iPhone’s Secure Enclave Processor (SEP), which is built into every iOS device with Touch ID or Face ID. That’s the processor that handles data encryption on the device – a processor that oh, so many law enforcement and hacker types spend so much time complaining about… or, as the case may be, cracking for fun, fame and profit. After you set it up, you’ll just need your iPhone or iPad, and your usual password, to use in 2FA when you sign in to Google on a desktop using Chrome.
A big plus: it uses a Bluetooth connection, rather than sending a code via SMS that could be intercepted in a SIM swap attack. In a SIM-swap fraud attack, a hijacker gets their hands on a phone number – typically by sweet-talking/social-engineering it away from its rightful owner – after which they can intercept the codes sent for 2FA that the phone number’s rightful owner set up to protect their accounts.
Source: sophos.com