Being authentic is a high term of praise—if we think people are authentic, we believe them to be trustworthy, loyal, and dependable. There's a similar concept in computer security. Business networks are crucial to protect, so firms want only authorised people accessing them. In cybersecurity, authentication means verifying that a person or device is who they claim to be. It usually involves checking the identity claim against what's called a factor. This could be a password, a biometric identifier (a fingerprint, an iris scan), or the ability to control a trusted piece of equipment such as an electronic ID card or a cell phone. There are several options available today: single factor, two-factor, multi-factor (this can go up to three-, four-, or five-factor), and adaptive multi-factor authentication. Each choice has benefits and risks—let’s explore them. Single-Factor Authentication Authenticating identity claims against a single factor is the main way computer security.