Gartner Research

A Taxonomy of User Authentication Methods

Published: 01 April 2014

ID: G00262913

Analyst(s): Ant Allan


The variety of user authentication methods can no longer be usefully described by counting factors. Information security and IAM leaders and technical professionals can use this fine-grained taxonomy to inform discussion of the differences in trust and user experience among different methods.

Table Of Contents


  • What Is User Authentication, and How Does It Work?
  • What Kinds of Credentials Are There?
  • Knowledge Methods
  • Tokens
    • OOB Authentication Methods
    • OTP Tokens
    • Public-Key Tokens
    • Other Tokens
  • Biometric Methods
  • Inferential Methods
  • Q&A Methods
  • Contextual Methods
  • Summary

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