Please add your suggestions for this list of widely-deployed MFA technologies to this list. We're primarily looking for classes of technologies (e.g., smart phone app or key fob), but feel free to specify vendors or products, if you think they warrant individual mention.
- Second factor only (used in conjunction with username/password)
- Duo
- OTP tokens (Do we care if these are hardware or software? Does this include SMS codes?)
- U2F
- Mobile app (Duo, Google Authenticator)
- Telephone callback (IVR)
- Multi-factor tokens
- PKI with PIN or passphrase