In order to strengthen its user and data security features, Yahoo has launched second sign-in verification and App Passwords.
Similar to Google’s two-factor verification, Yahoo’s second sign-in verification adds an extra level of protection for your Yahoo account. In the event that your account is accessed from an unrecognized device, Yahoo will require verification through your security question or mobile number.
Note, though, that certain apps, including the Mail apps on iOS and Android, don’t work with Yahoo’s second sign-in verification. For this reason, Yahoo is also implementing App Passwords.