US5115467A
Expired / Lapsed
US
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Signal encryption apparatus for generating common and distinct keys
Assignee: Arris Technology Inc
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Filing: 1991-01-23
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Granted: 1992-05-19
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Expires: 2011-01-23
Abstract
Abstract Signal encryption apparatus is provided for generating a common key and a distinct key from the same common secret generating key. A generating key is combined with common parameter data to provide a common intermediate key. The common intermediate key is used to produce a common key. The generating key is also combined with distinct parameter data to provide a distinct intermediate key. The distinct intermediate key is used to produce a distinct key. The system has particular applicability to the provision of category and program keys for use in a satellite television scrambling system. The generating key is used to produce the same category key at all uplinks, and different program keys at each uplink.
Inventors
- 👤 James N. Esserman
- 👤 Christopher J. Bennett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 02:08
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/16; H04N7/167; H04N7/1675; H04L; H04L9/00; H04L9/08; H04L9/0816; H04L9/0819; H04L9/083; H04L9/0833; H04N21/00; H04N21/20; H04N21/25; H04N21/266; H04N21/26606
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
165 words
A method for locally generating common and distinct cryptographic keys at a plurality of sites comprising the steps of: initializing a terminal for each site with a set of distinct parameter data unique to the site, a common secret generating key that is the same for all sites, and a set of common parameter data that is the same for all sites; combining the generating key with the set of common parameter data in each terminal to provide a common intermediate key that is the same for all sites; transforming the common intermediate key through a first one way function in each terminal into a common key that is the same for all sites; combining the generating key with the set of distinct parameter data in each terminal to provide a distinct intermediate key that is unique for each site; and transforming the distinct intermediate key through a second one way function in each terminal into a distinct key that is unique for each site.
Claim 2
Independent Claim
165 words
A method for locally generating common and distinct cryptographic keys at a plurality of sites comprising the steps of: initializing a terminal for each site with a set of distinct parameter data unique to the site, a common secret generating key that is the same for all sites, and a set of common parameter data that is the same for all sites; combining the generating key with the set of common parameter data in each terminal to provide a common intermediate key that is the same for all sites; transforming the common intermediate key through a first one way function in each terminal into a common key that is the same for all sites; combining the generating key with the set of distinct parameter data in each terminal to provide a distinct intermediate key that is unique for each site; and transforming the distinct intermediate key through a second one way function in each terminal into a distinct key that is unique for each site.
Claim 3
Dependent Claim
81 words
A method in accordance with claim 1 comprising the further steps of: providing a group of different sets of common parameter data for each terminal; combining said generating key with each set of common parameter data in each terminal to provide a group of different common intermediate keys that is the same for all sites; and transforming said group of different common intermediate keys in each terminal into a group of different common keys that is the same for all sites.
Claim 4
Dependent Claim
79 words
A method in accordance with claim 1 comprising the further steps of: providing a group of different sets of distinct parameter data for each terminal; combining said generating key with each set of distinct parameter data in each terminal to provide a group of different distinct intermediate keys that is unique for each site; and transforming said group of different distinct intermediate keys in each terminal into a group of different distinct keys that is unique for each site.
Claim 5
Dependent Claim
31 words
A method in accordance with claim 1 comprising the further step of: changing the set of common parameter data in accordance with a scheduling algorithm common to all of said terminals.
Claim 6
Dependent Claim
31 words
A method in accordance with claim 4 comprising the further step of: controlling said changing step to provide a new set of common parameter data that is different from previous sets.
Claim 7
Dependent Claim
23 words
A method in accordance with claim 4 comprising the further step of: changing a subset of the distinct parameter data for each terminal.
Claim 8
Dependent Claim
35 words
A method in accordance with claim 6 comprising the further step of: encrypting and storing at least one of said generating, common and distinct keys with a base key that is local to each site.
Claim 9
Dependent Claim
24 words
A method in accordance with claim 7 wherein each of said generating, common, and distinct keys is encrypted with said base key and stored.
Claim 10
Dependent Claim
57 words
A method in accordance with claim 8 wherein: said first one way function comprises an encryption of a quantity by the common intermediate key in each terminal to provide said common key; and said second one way function comprises an encryption of a quantity by the distinct intermediate key in each terminal to provide said distinct key.
Claim 11
Dependent Claim
23 words
A method in accordance with claim 1 comprising the further step of: changing a first subset of distinct parameter data for each terminal.
Claim 12
Dependent Claim
37 words
A method in accordance with claim 10 wherein a second subset of distinct parameter data at each terminal is not changed when the first subset is changed, to maintain said second subset unique for its associated site.
Claim 13
Dependent Claim
33 words
A method in accordance with claim 10 comprising the further step of: controlling said changing step to provide a new first subset of distinct parameter data that is different from previous first subsets.
Claim 14
Dependent Claim
35 words
A method in accordance with claim 1 comprising the further step of: encrypting and storing at least one of said generating, common and distinct keys with a base key that is local to each site.
Claim 15
Dependent Claim
24 words
A method in accordance with claim 13 wherein each of said generating, common, and distinct keys is encrypted with said base key and stored.
Claim 16
Dependent Claim
57 words
A method in accordance with claim 1 wherein: said first one way function comprises an encryption of a quantity by the common intermediate key in each terminal to provide said common key; and said second one way function comprises an encryption of a quantity by the distinct intermediate key in each terminal to provide said distinct key.
Claim 17
Dependent Claim
105 words
Signal encryption apparatus for generating a common key and a distinct key from a secret generating key comprising: first means for combining a secret generating key with a set of common parameter data to provide a common intermediate key; first one way function means, coupled to receive said common intermediate key, for transforming the common intermediate key into a common key; second means for combining said secret generating key with a set of distinct parameter data to provide a distinct intermediate key; and second one way function means, coupled to receive said distinct intermediate key, for transforming the distinct intermediate key into a distinct key.
Claim 18
Dependent Claim
105 words
Signal encryption apparatus for generating a common key and a distinct key from a secret generating key comprising: first means for combining a secret generating key with a set of common parameter data to provide a common intermediate key; first one way function means, coupled to receive said common intermediate key, for transforming the common intermediate key into a common key; second means for combining said secret generating key with a set of distinct parameter data to provide a distinct intermediate key; and second one way function means, coupled to receive said distinct intermediate key, for transforming the distinct intermediate key into a distinct key.
Claim 19
Dependent Claim
21 words
Apparatus in accordance with claim 16 further comprising: means for changing said common parameter data in accordance with a scheduling algorithm.
Claim 20
Dependent Claim
55 words
Apparatus in accordance with claim 16 wherein: said first means combines a group of different sets of common parameter data with said generating key to provide a group of different common intermediate keys; and said first one way function means transforms said group of different common intermediate keys into a group of different common keys.
Claim 21
Dependent Claim
18 words
Apparatus in accordance with claim 16 further comprising: means for changing a subset of said distinct parameter data.
Claim 22
Dependent Claim
33 words
Apparatus in accordance with claim 16 further comprising: means for encrypting and storing at least one of said generating, common and distinct keys with a base key that is local to each site.
Claim 23
Dependent Claim
23 words
Apparatus in accordance with claim 20 wherein each of said generating, common, and distinct keys is encrypted with said base key and stored.
Claim 24
Dependent Claim
46 words
Apparatus in accordance with claim 16 wherein: said first one way function means encrypt a quantity by the common intermediate key to provide said common key; and said second one way function means encrypt a quantity by the distinct intermediate key to provide said distinct key.
Claim 25
Dependent Claim
55 words
Apparatus in accordance with claim 16 wherein: said second means combines a group of different sets of distinct parameter data with said generating key to provide a group of different distinct intermediate keys; and said second one way function means transforms said group of different distinct intermediate keys into a group of different distinct keys.
References Cited (Backward Citations)
US4613901A
Cited
US5016276A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-05-19 | 1995-11-18 | 1996-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-05-19 | 1999-11-18 | 2000-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-05-19 | 2003-11-18 | 2004-05-19 | $7700.00 | Window Closed / Lapsed |