US5404403A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Key management in encryption systems
Assignee: Motorola Solutions Inc
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Filing: 1991-11-12
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Granted: 1995-04-04
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Expires: 2011-11-12
Abstract
Abstract A key management system for encryption keys removes the effect of secure communications loss during a rekey period in a secure communications system. Use of key indexes to partition encryption keys into usable subgroups such that during a rekey period, continuous secure communications are maintained throughout the entire secure communications system.
Inventors
- 👤 Michael W. Bright
- 👤 David L. Weiss
- 👤 Kevin M. Cutts
- 👤 Robert J. Locascio
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:19
CPC Classifications
H; H04; H04L; H04L9/00; H04L9/08; H04L9/0816; H04L9/0819; H04L9/083; H04L9/0891; H04L2209/00; H04L2209/80
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
98 words
A key management system for use in a secure communications system having at least two communication units, the system comprising: means for storing at least a first encryption key in an active index; means for operating a communication unit from said active index during a first cryptographic period, wherein said communication unit is one of the at least two communication units; means for storing at least a second encryption key in an inactive index during said first cryptographic period; and means for changing to operation of said communication unit from said inactive index during a second cryptographic period.
Claim 2
Dependent Claim
98 words
A key management system for use in a secure communications system having at least two communication units, the system comprising: means for storing at least a first encryption key in an active index; means for operating a communication unit from said active index during a first cryptographic period, wherein said communication unit is one of the at least two communication units; means for storing at least a second encryption key in an inactive index during said first cryptographic period; and means for changing to operation of said communication unit from said inactive index during a second cryptographic period.
Claim 3
Dependent Claim
21 words
The key management system of claim 1 further comprising means for naming said at least two indexes with a vernacular name.
Claim 4
Dependent Claim
20 words
The key management system of claim 1 further comprising means, coupled to said means for dividing, for variable key indexing.
Claim 5
Dependent Claim
19 words
The key management system of claim 1 further comprising means, coupled to said means for retaining, for index zeroizing.
Claim 6
Independent Claim
92 words
A method for key management for use in a secure communications system having at least two communication units, comprising the steps of: storing at least a first encryption key in an active index; operating a communication unit from said active index during a first cryptographic period, wherein said communication unit is one of the at least two communication units; storing at least a second encryption key in an inactive index during said first cryptographic period; and changing to operation of said communication unit from said inactive index during a second cryptographic period.
Claim 7
Independent Claim
92 words
A method for key management for use in a secure communications system having at least two communication units, comprising the steps of: storing at least a first encryption key in an active index; operating a communication unit from said active index during a first cryptographic period, wherein said communication unit is one of the at least two communication units; storing at least a second encryption key in an inactive index during said first cryptographic period; and changing to operation of said communication unit from said inactive index during a second cryptographic period.
Claim 8
Dependent Claim
20 words
The method of claim 5 further comprising the step of naming said at least two indexes with a vernacular name.
Claim 9
Dependent Claim
27 words
The method of claim 5 further comprising the step of variably indexing at least one of said multiple encryption keys, in response to said step of dividing.
Claim 10
Dependent Claim
19 words
The method of claim 5 further comprising the step of index zeroizing, in response to said step of retaining.
Claim 11
Dependent Claim
117 words
A key management system for use in a secure communications system having at least two communication units, comprising: means for storing at least a first encryption key in an active index; means for operating a communication unit from said active index during a first cryptographic period, wherein said communication unit is one of the at least two communication units; means for storing at least a second encryption key in an inactive index during said first cryptographic period; means for changing to operation of said communication unit from said inactive index during a second cryptographic period; means, coupled to said means for dividing, for variable key indexing; and means, coupled to said means for retaining, for index zeroizing.
Claim 12
Dependent Claim
117 words
A key management system for use in a secure communications system having at least two communication units, comprising: means for storing at least a first encryption key in an active index; means for operating a communication unit from said active index during a first cryptographic period, wherein said communication unit is one of the at least two communication units; means for storing at least a second encryption key in an inactive index during said first cryptographic period; means for changing to operation of said communication unit from said inactive index during a second cryptographic period; means, coupled to said means for dividing, for variable key indexing; and means, coupled to said means for retaining, for index zeroizing.
Claim 13
Dependent Claim
21 words
The key management system of claim 9 further comprising means for naming said at least two indexes with a vernacular name.
Claim 14
Independent Claim
118 words
A method for key management for use in a secure communications system having at least two communication units, comprising the steps of: storing at least a first encryption key in an active index; operating a communication unit from said active index during a first cryptographic period, wherein said communication unit is one of the at least two communication units; storing at least a second encryption key in an inactive index during said first cryptographic period; changing to operation of said communication unit from said inactive index during a second cryptographic period; variably indexing at least one of said multiple encryption keys, in response to said step of dividing; and index zeroizing, in response to said step of retaining.
Claim 15
Independent Claim
118 words
A method for key management for use in a secure communications system having at least two communication units, comprising the steps of: storing at least a first encryption key in an active index; operating a communication unit from said active index during a first cryptographic period, wherein said communication unit is one of the at least two communication units; storing at least a second encryption key in an inactive index during said first cryptographic period; changing to operation of said communication unit from said inactive index during a second cryptographic period; variably indexing at least one of said multiple encryption keys, in response to said step of dividing; and index zeroizing, in response to said step of retaining.
Claim 16
Dependent Claim
20 words
The method of claim 11 further comprising the step of naming said at least two indexes with a vernacular name.
Claim 17
Dependent Claim
106 words
A secure communication unit for use in a secure communications system, wherein the subscriber uses a key management system, comprising: means for storing at least a first encryption key in an active index; means for operating a communication unit from said active index during a first cryptographic period; means for storing at least a second encryption key in an inactive index during said first cryptographic period; means for changing to operation of said communication unit from said inactive index during a second cryptographic period; means, coupled to said means for dividing, for variable key indexing; and means, coupled to said means for retaining, for index zeroizing.
Claim 18
Dependent Claim
106 words
A secure communication unit for use in a secure communications system, wherein the subscriber uses a key management system, comprising: means for storing at least a first encryption key in an active index; means for operating a communication unit from said active index during a first cryptographic period; means for storing at least a second encryption key in an inactive index during said first cryptographic period; means for changing to operation of said communication unit from said inactive index during a second cryptographic period; means, coupled to said means for dividing, for variable key indexing; and means, coupled to said means for retaining, for index zeroizing.
Claim 19
Dependent Claim
21 words
The secure communication unit of claim 13 further comprising means for naming said at least two indexes with a vernacular name.
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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) | 1998-04-03 | 1998-10-03 | 1999-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-04-03 | 2002-10-03 | 2003-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-04-03 | 2006-10-03 | 2007-04-04 | $7700.00 | Window Closed / Lapsed |