Authentication

Authentication is a process used in computing and information security to verify the identity of a user, process, or device as a prerequisite to allowing access to resources in a system. It's a critical component of most security strategies, ensuring that only authorized entities can access protected resources such as data, systems, and networks.

Authentication typically involves validating credentials, which can include things like usernames, passwords, digital certificates, or biometric data.

Types of Authentication Factors:

• Knowledge Factors: Something the user knows (e.g., password, PIN).
• Possession Factors: Something the user has (e.g., security token, smartphone).
• Inherence Factors: Something the user is (e.g., biometric verification like fingerprints or facial recognition).
• Location Factors: Somewhere the user is (e.g., accessing from a specific location).
• Behavior Factors: Something the user does (e.g., typing patterns).

Combining two or more different types of authentication factors significantly increases security. For example, a system may require a password (something the user knows) and a one-time code from a smartphone (something the user has) - known as Multi-Factor Authentication (MFA).

Single Sign-On (SSO) allows user to authenticate once and gain access to multiple systems without being prompted to log in again for each system.

Various protocols facilitate authentication including Kerberos Authentication|Kerberos, Lightweight Directory Access Protocol|LDAP, OAuth, and SAML (Security Assertion Markup Language).

Authentication is a fundamental part of access control systems, determining whether a user should be allowed access to a system or resource. It helps in protecting systems from unauthorized access, thus safeguarding sensitive data and resources. In digital communications and transactions, authentication establishes trust by ensuring that entities involved are who they claim to be.