US4944007A
Expired / Lapsed
US
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Public key diversification method
Assignee: NCR Voyix Corp
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Filing: 1989-06-12
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Granted: 1990-07-24
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Expires: 2009-06-12
Abstract
Abstract A method is disclosed whereby individual members of a group of members or entities may be provided, under the control of a trusted member, referred to as the parent, with respective individual secret keys for use in public key cryptography, such that the matching public key can be readily derived, and group membership authenticated. The parent initially establishes a public key (e,N) where N=P.Q is the product of two primes. In response to a request from a group member, the parent selects two further primes R,S and communicates two values dependent thereon to the requesting member, which selects two more primes T and U for use in conjunction with the received values to establish the member's secret key.
Inventors
- 👤 Jeffrey R. Austin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:47
CPC Classifications
G; G06; G06Q; G06Q20/00; G06Q20/30; G06Q20/36; G06Q20/367; G06Q20/3672; H; H04; H04L; H04L9/00; H04L9/08; H04L9/0861; H04L9/0877; H04L9/30; H04L9/3006; H04L9/302; H04L9/32; H04L9/3247; H04L2209/00; H04L2209/56
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
189 words
A method of generating key values for use in public key cryptography by a requesting entity, including the step of generating at a parent entity, public key values N, e, where N is the product of first and second prime numbers P,Q and e is a corresponding public key integer value, comprising: selecting, at said parent entity, third and fourth prime numbers R,S; transmitting to said requesting entity a first value N mi and a second value Φ(N mi ) where said first value N mi =N·R·S and where said second value Φ(N mi )=Φ(N)·(R-1)·(S-1), wherein the symbol Φ represents Euler's totient function; selecting, at said requesting entity, fifth and sixth prime numbers, T,U; and computing, at said requesting entity, a third value N m and a fourth value d m , where N m =N mi ·T·U, and where d m =[1+K Φ(N m )]/e; wherein Φ(N m )=Φ(N mi )·(T-1)·(U-1); and wherein K and d m are integers, whereby d m is adapted to be used by said requesting entity as a secret key counterpart of the public key value e with respect to N m .
Claim 2
Independent Claim
189 words
A method of generating key values for use in public key cryptography by a requesting entity, including the step of generating at a parent entity, public key values N, e, where N is the product of first and second prime numbers P,Q and e is a corresponding public key integer value, comprising: selecting, at said parent entity, third and fourth prime numbers R,S; transmitting to said requesting entity a first value N mi and a second value Φ(N mi ) where said first value N mi =N·R·S and where said second value Φ(N mi )=Φ(N)·(R-1)·(S-1), wherein the symbol Φ represents Euler's totient function; selecting, at said requesting entity, fifth and sixth prime numbers, T,U; and computing, at said requesting entity, a third value N m and a fourth value d m , where N m =N mi ·T·U, and where d m =[1+K Φ(N m )]/e; wherein Φ(N m )=Φ(N mi )·(T-1)·(U-1); and wherein K and d m are integers, whereby d m is adapted to be used by said requesting entity as a secret key counterpart of the public key value e with respect to N m .
Claim 3
Dependent Claim
29 words
A method according to claim 1 wherein said parent entity includes storage means, said method further comprising: storing the values of N, Φ(N) and e in said storage means.
Claim 4
Dependent Claim
32 words
A method according to claim 2, further comprising: storing in said storage means an identification code identifying said requesting entity, said first value N mi and said second value Φ(N mi ).
Claim 5
Dependent Claim
45 words
A method according to claim 3 wherein said requesting entity includes further storage means, said method further comprising: computing, at said requesting entity, a fifth value N mv , where N mv =N m /N; and storing said fifth value in said further storage means.
Claim 6
Dependent Claim
37 words
A method according to claim 4, further comprising: multiplying the value N mv by the value N to yield the value N m , utilization of which, with the value e, enables the verification of digital signatures.
Claim 7
Dependent Claim
17 words
A method according to claim 6 wherein said public key integer value e is a prime number.
Claim 8
Dependent Claim
36 words
A method according to claim 4, further comprising: multiplying the value N mv by the value N to yield the value N m , utilization of which, with the value e, enables the enciphering of data.
Claim 9
Dependent Claim
17 words
A method according to claim 1 wherein said public key integer value e is a prime number.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-23 | 1994-01-22 | 1994-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-23 | 1998-01-22 | 1998-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-23 | 2002-01-22 | 2002-07-24 | $7700.00 | Window Closed / Lapsed |