Secure communication system for re-establishing time limited communication between first and second computers before communication time period expiration using new random number
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United States of America Patent
Stats
-
Jun 27, 1995
Issued Date -
N/A
app pub date -
Jul 25, 1994
filing date -
Jun 12, 1992
priority date (Note) -
Expired
status (Latency Note)
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Abstract
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.
First Claim
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- 15 United States
- 10 France
- 8 Japan
- 7 China
- 5 Korea
- 2 Other
Patent Owner(s)
| Patent Owner | Address | |
|---|---|---|
| DOW CHEMICAL COMPANY THE | 2030 DOW CENTRE ABBOTT ROAD MIDLAND MICHIGAN 48640 UNITED STATES OF AMERICA |
International Classification(s)
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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Maintenance Fees
| Fee | Large entity fee | small entity fee | micro entity fee | due date |
|---|
| Fee | Large entity fee | small entity fee | micro entity fee |
|---|---|---|---|
| Surcharge after expiration - Late payment is unavoidable | $700.00 | $350.00 | $175.00 |
| Surcharge after expiration - Late payment is unintentional | $1,640.00 | $820.00 | $410.00 |
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