US5241597A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for recovering from encryption key variable loss
Assignee: Motorola Solutions Inc
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Filing: 1991-02-01
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Granted: 1993-08-31
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Expires: 2011-02-01
Abstract
Abstract A method for recovering from encryption key variable loss, either inadvertent or the result of tampering. A predetermined key encryption key is encrypted with itself at the time when keys are first loaded, and the resultant key loss key is stored in non-volatile memory. This key loss key acts as a key encryption key for decryption of new shadow and traffic keys.
Inventors
- 👤 Michael W. Bright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:26
CPC Classifications
H; H04; H04L; H04L9/00; H04L9/06; H04L9/065; H04L9/08; H04L9/0894
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
64 words
A method for recovering from key variable loss, the method comprising the steps of: (a) deriving a new key encryption key from a previously stored key and storing the result in non-volatile memory as a key loss key; (b) decrypting a transmitted key using the new key encryption key; and (c) storing the decrypted key for use in decrypting additional keys and/or information signals.
Claim 2
Independent Claim
64 words
A method for recovering from key variable loss, the method comprising the steps of: (a) deriving a new key encryption key from a previously stored key and storing the result in non-volatile memory as a key loss key; (b) decrypting a transmitted key using the new key encryption key; and (c) storing the decrypted key for use in decrypting additional keys and/or information signals.
Claim 3
Dependent Claim
26 words
The method in accordance with claim 1, wherein the step (a) of deriving a new key encryption key comprises encrypting the previously stored key with itself.
Claim 4
Dependent Claim
62 words
Apparatus for recovering from key variable loss, the apparatus comprising: means for deriving a new key encryption key from a previously stored key and storing the result in non-volatile memory as a key loss key; means for decrypting a transmitted key using the new key encryption key; means for storing the decrypted key for use in decrypting additional keys and/or information signals.
Claim 5
Dependent Claim
62 words
Apparatus for recovering from key variable loss, the apparatus comprising: means for deriving a new key encryption key from a previously stored key and storing the result in non-volatile memory as a key loss key; means for decrypting a transmitted key using the new key encryption key; means for storing the decrypted key for use in decrypting additional keys and/or information signals.
Claim 6
Dependent Claim
96 words
A communication unit for use in a secure RF communication system, the communication unit comprising: transmitter means for transmitting RF signals; receiver means for receiving RF signals; an encryption subsystem coupled to the transmitter means and the receiver means, wherein the encryption subsystem comprises: means for deriving a new key encryption key from a previously stored key and storing the result in non-volatile memory as a key loss key; means for decrypting a transmitted key using the new key encryption key; means for storing the decrypted key for use in decrypting additional keys and/or information signals.
Claim 7
Dependent Claim
96 words
A communication unit for use in a secure RF communication system, the communication unit comprising: transmitter means for transmitting RF signals; receiver means for receiving RF signals; an encryption subsystem coupled to the transmitter means and the receiver means, wherein the encryption subsystem comprises: means for deriving a new key encryption key from a previously stored key and storing the result in non-volatile memory as a key loss key; means for decrypting a transmitted key using the new key encryption key; means for storing the decrypted key for use in decrypting additional keys and/or information signals.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-30 | 1997-03-01 | 1997-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-30 | 2001-03-01 | 2001-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-30 | 2005-03-01 | 2005-08-31 | $7700.00 | Window Closed / Lapsed |