An anonymous reader writes: "The U.S. National Institute for Standards and Technology (NIST) has released the latest draft version of the Digital Authentication Guideline that contains language hinting at a future ban of SMS-based Two-Factor Authentication (2FA)," reports Softpedia. The NIST DAG draft argues that SMS-based two-factor authentication is an insecure process because the phone may not always be in possession of the phone number, and because in the case of VoIP connections, SMS messages may be intercepted and not delivered to the phone. The guideline recommends the usage of tokens and software cryptographic authenticators instead. Even biometrics authentication is considered safe, under one condition: "Biometrics SHALL be used with another authentication factor (something you know or something you have)," the guideline's draft reads. The NIST DAG draft reads in part: "If the out of band verification is to be made using a SMS message on a public mobile telephone network, the verifier SHALL verify that the pre-registered telephone number being used is actually associated with a mobile network and not with a VoIP (or other software-based) service. It then sends the SMS message to the pre-registered telephone number. Changing the pre-registered telephone number SHALL NOT be possible without two-factor authentication at the time of the change. OOB using SMS is deprecated, and will no longer be allowed in future releases of this guidance."