2FA

Passguard works with all services that provide two-factor authentication using the HOTP and TOTP algorithms. It does not require a network or cellular connection and can be used in airplane mode.

U2F

Basically you make a challenge online. Then solve it offline And broadcast it online to prove you are you. Via NFC or Bluetooth Passguard will be able to support U2F.

Read more: Yubi U2F