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 Title: |
US4200770:
Cryptographic apparatus and method
[ Derwent Title ]
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| Country: |
US United States of America
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| Inventor: |
Hellman, Martin E.; Stanford, CA
Diffie, Bailey W.; Berkeley, CA
Merkle, Ralph C.; Palo Alto, CA
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| Assignee: |
Stanford University, Palo Alto, CA
other patents from STANFORD UNIVERSITY (675809) (approx. 1,667)
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| Published / Filed: |
1980-04-29
/ 1977-09-06
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| Application Number: |
US1977000830754
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| IPC Code: |
Advanced:
H04L 9/08;
Core:
more...
IPC-7:
H04L 9/04;
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| ECLA Code: |
H04L9/08D;
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| U.S. Class: |
Current:
380/030;
380/044;
380/285;
713/169;
713/171;
Original:
178/022;
340/149.R;
375/002;
455/026;
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| Field of Search: |
178/022
340/149 R
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| Government Interest: |
The Government has rights in this invention pursuant to Grant No. ENG-10173 of the National Science Foundation and IPA No. 0005.
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| Priority Number: |
| 1977-09-06 |
US1977000830754 |
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| Abstract: |
A cryptographic system transmits a computationally secure cryptogram over an insecure communication channel without prearrangement of a cipher key. A secure cipher key is generated by the conversers from transformations of exchanged transformed signals. The conversers each possess a secret signal and exchange an initial transformation of the secret signal with the other converser. The received transformation of the other converser's secret signal is again transformed with the receiving converser's secret signal to generate a secure cipher key. The transformations use non-secret operations that are easily performed but extremely difficult to invert. It is infeasible for an eavesdropper to invert the initial transformation to obtain either conversers' secret signal, or duplicate the latter transformation to obtain the secure cipher key.
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| Attorney, Agent or Firm: |
Flehr, Hohbach, Test ;
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| Primary / Asst. Examiners: |
Birmiel, Howard A.;
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| Family: |
None
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First Claim:
Show all 8 claims |
What is claimed is:
1. A secure key generator comprising:
- a first input connected to receive an applied first signal;
- a second input connected to receive an applied second signal;
- a first output;
- a second output; and
- means for generating at the first output a third signal, that is a transformation of said first signal and which transformation is infeasible to invert, and for generating at the second output a fourth signal, that is a transformation of said second signal with said first signal, which represents a secure key and is infeasible to generate solely with said second signal and said third signal.
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| Background / Summary: |
Show background / summary
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| Drawing Descriptions: |
Show drawing descriptions
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| Description: |
Show description
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| Forward References: |
Show 440 U.S. patent(s) that reference this one
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