Authentication is the process of verifying the identity of a user or system. It ensures that the person or entity trying to access a resource is who they claim to be. Common methods of authentication include passwords, biometric data like fingerprints, and security tokens. In digital systems, authentication is crucial for protecting sensitive information. For example, when you log into your email account, the system checks your credentials against stored data to confirm your identity. This helps prevent unauthorized access and keeps your data secure from potential threats like hackers or phishing attacks.