Login - online puzzles

In computer security, logging in (or logging on or signing in or signing on) is the process by which an individual gains access to a computer system by identifying and authenticating themselves. The user credentials are typically some form of "username" and a matching " password ", and these credentials themselves are sometimes referred to as a login, (or a logon or a sign -in or a sign -on). In practice, modern secure systems also often require a second factor for extra security.

When access is no longer needed, the user can log out (log off, sign out or sign off).