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User authentication

User authentication

(also access control or identity verification)

User authentication definition

User authentication constitutes confirming a user’s identity when they strive to access a system or network. This component is critical for system security because it affirms that access to confidential data or resources is granted solely to those with proper authorization. During the authentication process, users are typically required to provide some form of credentials or evidence to prove their identity.

See also: two-factor authentication

User authentication examples

  • Passwords: The most common form of user authentication, where users are required to enter a unique string of characters to prove their identity.
  • Two-factor authentication (2FA): An enhanced form of authentication where users must provide two pieces of evidence to prove their identity. For example, something they know (a password), and something they have (a token or mobile device).

Advantages and disadvantages of user authentication


  • Security: User authentication is a crucial line of defense against unauthorized access to sensitive data and systems.
  • Accountability: It provides an audit trail, which can be used to trace and investigate suspicious activities.


  • Usability: Strong authentication mechanisms can be seen as inconvenient, especially if they require additional steps or devices.
  • Vulnerability: Despite the benefits, no authentication method is completely immune to attacks. For instance, passwords can be guessed or stolen, and biometrics can be faked.

Using user authentication

  • Always implement at least one form of user authentication for any system or network that houses sensitive data.
  • Encourage the use of multi-factor authentication (MFA) because it provides an additional layer of security beyond just a username and password.

Further reading

Ultimate digital security