Abstract: An improved computer security system including a portable, electronic Key, an Access Device with Touch Pad, a Lock, a Lock Server and Server Device, and a Master Device. The Access Device provides a means to validate the user to the Key. The Lock is physically located with, and connected to the host computer. Improved security is achieved through the use of "throw-away" passwords, which are generated in a random fashion by the Lock Server, and then loaded directly into volatile memory of Keys, but transferred to a Master Device for loading into volatile memory of Locks. These throw-away passwords are used in a process of cross validation between the Lock and Key, a requirement before access to the host computer is granted. A user specific "touch-print" provides a more secure and more user friendly way of preventing the use of Keys by unauthorized persons. Sensors, e.g., photosensors, within the Key, Lock and Master Device guard against physical attacks.