AuthLite Interactive Documentation
FEATURES: What can AuthLite Do? TOKEN TYPES: What "Factors" are supported? INSTALL: How and where to install AuthLite? CONFIGURE AuthLite for your needs CHOOSE USERS: Choose 2-factor Users ENFORCE 2-factor Logons ADMINISTER AuthLite Tokens LDAP logon support/enforcement VPN and RADIUS Configuration How to Log In Event Logging

Using the SMS protocol to send authentication codes is generally not considered secure, since the mobile phone network is not well encrypted.  Most use cases can be covered either by using an app on your user's smart phone, or a hardware token.