US6069957A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for providing hierarchical key system in restricted-access television system
Assignee: Nokia of America Corp
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Filing: 1997-03-07
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Granted: 2000-05-30
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Expires: 2017-03-07
Abstract
Abstract An encryption system for restricted-access television systems. Decryption keys, which are used to decrypt program material, are transmitted to customers in a restricted-access television system. The keys are transmitted as a hierarchy, wherein one key unlocks another key, and the last key unlocked is used to decrypt program material. Such a hierarchy is sometimes called "key-upon-key" encryption. The system transmits a second key that produces a first key from a cipher text (which first key decrypts a first program material) and wherein the second key also decrypts a second program material.
Inventors
- 👤 William James Richards
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:20
CPC Classifications
H; H04; H04L; H04L9/00; H04L9/08; H04L9/0816; H04L9/0819; H04L9/083; H04L9/0833; H04L9/0836; H04L2209/00; H04L2209/60; H04L2209/601
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
42 words
In a restricted-access television system, the improvement comprising the following steps: a) transmitting a first key which decrypts first program material; and b) transmitting a second key which i) produces the first key from cipher text; and ii) decrypts second program material.
Claim 2
Dependent Claim
42 words
In a restricted-access television system, the improvement comprising the following steps: a) transmitting a first key which decrypts first program material; and b) transmitting a second key which i) produces the first key from cipher text; and ii) decrypts second program material.
Claim 3
Dependent Claim
43 words
In a restricted-access television system, the improvement comprising: a) means for transmitting a first key which decrypts first program material; and b) means for transmitting a second key which i) produces the first key from cipher text; and ii) decrypts second program material.
Claim 4
Dependent Claim
43 words
In a restricted-access television system, the improvement comprising: a) means for transmitting a first key which decrypts first program material; and b) means for transmitting a second key which i) produces the first key from cipher text; and ii) decrypts second program material.
References Cited (Backward Citations)
US5237610A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-05-30 | 2003-11-29 | 2004-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-05-30 | 2007-11-29 | 2008-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-05-30 | 2011-11-29 | 2012-05-30 | $7700.00 | Window Closed / Lapsed |