Which of the following describes a method to secure doors without a physical key?

The concept of securing doors without a physical key is significantly embodied by electronic keypads. This method allows users to enter a numerical code to unlock the door, eliminating the need for a physical key and enhancing convenience and security. Electronic keypads are often used in residential and commercial settings, providing a way to control access without traditional lock-and-key systems, facilitating remote access, and enabling the temporary sharing of access codes.

Smart locks also utilize technology to secure doors but typically rely on a smartphone app or Bluetooth for operation, which can also be keyless. However, the question specifically highlights a method focused on numerical input rather than mobile device interaction. Deadbolts and rim locks, while effective in providing security, fundamentally rely on physical keys for operation and do not accommodate keyless entry options. Thus, the electronic keypad stands out as a clear and distinct method for securing doors without the need for a physical key.