How do we know master key?

The term "master key" often refers to a key that can open multiple locks, typically within a specific system or building. In security systems, master keys are designed through a controlled keying process that allows for hierarchical access. Knowledge of a master key typically comes from the locksmith or security system designer, who sets up the keying arrangement, ensuring that authorized individuals have access while maintaining security for others. Access to a master key should be strictly managed to prevent unauthorized use.