Abstract: The new seal monitor uses of a time dependant pseudo random number or a number from a time pad, which are lists of random numbers often used in encryption. This number changes periodically, for example, once an hour or whatever time interval is deemed timely by the particular application. It is intended that a remote monitoring station would send a request to the monitor and the monitor would respond with the random number that dependant on the time the monitor was started and how much time has elapsed. If the random number returned is correct it infers that the monitor is operating correctly and the seal has not been tampered with. If the monitor does not respond or responds with an incorrect number then the monitor or the seal has been tampered with. Light through a cable is periodically compared with historic outputs from that cable.

Abstract: Self-monitoring seals have ends of fiber optic bundle loops mounted in stressed tamper resistant containers. A battery operates microelectronics to change a display in predetermined sequence. Tampering with the container or interrupting or changing the light transmission through the fiber optic bundle disrupts the predetermined display sequence.