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This patent was reissued on June 27, 2000 as patent
USRE36752
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 Title: |
US5377270:
Cryptographic authentication of transmitted messages using pseudorandom numbers
[ Derwent Title ]
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| Country: |
US United States of America
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| Inventor: |
Koopman, Jr., Philip J.; Hebron, CT
Finn, Alan M.; Amston, CT
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| Assignee: |
United Technologies Automotive, Inc., Dearborn, MI
other patents from UNITED TECHNOLOGIES AUTOMOTIVE, INC. (597540) (approx. 411)
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| Published / Filed: |
1994-12-27
/ 1993-06-30
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| Application Number: |
US1993000085423
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| IPC Code: |
Advanced:
E05B 49/00;
E05B 65/20;
G09C 1/00;
H04L 9/12;
H04L 9/20;
H04L 9/32;
Core:
H04L 9/18;
more...
IPC-7:
H04L 9/00;
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| ECLA Code: |
H04L9/12; H04L9/32B;
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| U.S. Class: |
Current:
380/262;
340/005.26;
340/005.74;
340/005.8;
380/046;
713/181;
Original:
380/025;
380/021;
380/023;
380/046;
380/048;
380/049;
340/825.31;
340/825.34;
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| Field of Search: |
380/004,21,23,24,25,30,43,46,48,49,50
340/825.31,825.34
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| Priority Number: |
| 1993-06-30 |
US1993000085423 |
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| Abstract: |
An automobile door lock receiver module (30) and a plurality of keychain fob transmitter units (16) contain identification numbers, secret initial values, and secret feedback masks so as to authenticate encrypted messages from any of the assigned fobs, indicative of commands registered by closing switches on the fob. Each fob is synchronized with the receiving module by means of a truly random number concatenated with a secret initial value and encrypted, through a linear feedback shift register or other operations. A second secret initial value is encrypted and command bits are exclusive ORed into the low order bit positions; the two encrypted numbers are concatenated and encrypted to form a key word which is transmitted with the fob ID. Synchronization includes decrypting to recover the truly random number and the secret initial value concatenated therewith; the truly random number is compared with previously received random numbers in order to avoid copying of recently transmitted synchronization commands. Successive lock-related commands utilize the number encrypted from the truly random number and the second secret initial value as starting values, employing a pseudorandom number of encryption iterations. A half-second delay between responses mitigates gaining access through numerical trials. An authenticated panic alarm command operates the headlights and horn of the vehicle but does not alter the synchronization.
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| Attorney, Agent or Firm: |
Williams, M. P. ;
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| Primary / Asst. Examiners: |
Gregory, Bernarr E.;
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| INPADOC Legal Status: |
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| Family: |
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First Claim:
Show all 40 claims |
We claim:
1. A method of cryptographically authenticating a transmission from a transmitting unit at a receiving module, comprising:
- providing a secret initial value in said transmitter and providing said secret initial value in said receiver;
- in said transmitting unit:
- generating a random number;
- concatenating said random number with a key word derived from said secret initial value to provide a combined word;
- performing an encryption operation on said combined word to provide an encrypted number; and
- transmitting a command word derived at least in part from said encrypted number and indicative of a command;
- comprising in said receiving module:
- receiving said command word;
- recovering said encrypted number from said received command word;
- performing a decryption operation on said recovered encrypted number to recover said combined word;
- comparing a second word derived from said secret initial value with the key word portion of said recovered combined word;
- storing the random number portion of said recovered combined word for future use in subsequent authentication operations;
- comparing the random number portion of said recovered combined word with a previously stored random number portion; and
- performing the command indicated by said command word only if said second secret initial value is identical to the initial value portion of said recovered combined word and said random number portion of said recovered combined word is different from said previously stored random number portion.
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| Background / Summary: |
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| Drawing Descriptions: |
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| Description: |
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| Forward References: |
Show 40 U.S. patent(s) that reference this one
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