Appeal No. 95-0143
Application 07/865,849
decrypts Q using the secret key, S, to get P and encrypts R using
P to get X. The key then sends X back to the lock. The lock
encrypts R using P to get X and compares the two. If there is a
match, the lock allows entry.
Using this process, Pogue meets the above mentioned
objectives, the private key as well as the secret key are never
transmitted. This provides a high level of security even if all
communication can be monitored and all aspects of the design are
known. In addition, only the key’s ID and the secret key are
stored in the key. This provides a simple design for the key
that can operate at very low power.
On the other hand, Clark does not meet these objectives.
Clark stores lock ID codes and their corresponding access codes
in the key which requires a much larger amount of memory storage
in the key. In addition, Clark does not provide a high level of
security as taught by Pogue because Clark transmits the access
code which can be intercepted by someone monitoring the
transmission, thereby allowing unauthorized persons to defeat the
security of the lock.
Those skilled in the art having both the teachings of Pogue
and Clark before them would have been led away from using the
Clark security system which does not provide a high degree of
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Last modified: November 3, 2007