Authentication flow diagram modeling user login interaction from initial screen through credential validation to access control. The sequence progresses from the authentication screen through a validation controller that branches on credential correctness, routing users to either the home screen on success or back to re-authentication on failure. This pattern demonstrates conditional branching and state transitions essential for secure user access management. Fork this diagram on Diagrams.so to customize credential validation logic, add multi-factor authentication steps, or integrate with identity providers. The detailed interaction sequence illustrates best practices for handling both successful and failed authentication attempts.