Secure communication system for re-establishing time limited communication between first and second computers before communication time period expiration using new random number

Number of patents in Portfolio can not be more than 2000

United States of America Patent

PATENT NO 5428745
SERIAL NO

08279697

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ATTORNEY / AGENT: (SPONSORED)

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Abstract

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A secure front-end communication system which couples a plurality of actively redundant process control computers to a computer network. The system includes a front end computer which is capable of establishing time limited communication contracts with one or more computer entity on the computer network. Each time limited communication contract is based upon an acceptable response to the transmission of an unpredicable signal from the front end computer, such as an encrypted transformation of a psuedo-random number generated by the front end computer. A security table is used to identify the network entities that are permitted to send write command messages to the process control computers to which the front end computer is connected. The front end computer also includes at least one permissive table which is used to determined whether a write command message from the network entity should be transmitted to the process control computer for which the message was intended.

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Patent Owner(s)

Patent OwnerAddress
DOW CHEMICAL COMPANY THE2030 DOW CENTRE ABBOTT ROAD MIDLAND MICHIGAN 48640 UNITED STATES OF AMERICA

International Classification(s)

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Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Bell, Brian G Midland, MI 2 91
de, Bruijn Ronny P St. Jansteen, NL 3 340
Schultz, Dale H Midland, MI 3 111
Schulze, Oscar E Midland, MI 3 104
van, Weele Leonardus A Terneuzen, NL 3 340
Verboven, Marc L K Nazareth, BE 2 91
Vermeire, Roger R Terneuzen, NL 3 340

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