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US4140873A
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Multi-mode digital enciphering system
Assignee: Datotek Inc
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Filing: 1977-09-09
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Granted: 1979-02-20
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Expires: 1997-09-09
Abstract
Abstract The specification discloses an electronic digital enciphering system which is selectively operable in a plurality of different modes. The system may be operated in an off-line mode for preparing enciphered message tapes prior to transmission via teleprinter message circuits. The system may also be operated in an on-line asynchronous mode wherein a sending station may asynchronously transmit enciphered data on-line to a remote receiving unit, synchronization being provided by the start/stop pulses of the individual digital characters. The system may also be operated in an on-line synchronous mode wherein a sending and a receiving unit are automatically synchronized in time by local self-contained clocks in order to bridge fades or interference in a transmission medium such as radio telegraph, or the like. The system may be utilized on either half-duplex or full-duplex communication channels.
Inventors
- 👤 Frederick A. Kinch, Jr.
- 👤 Barrie O. Morgan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:36
CPC Classifications
G; G09; G09C; G09C3/00; H; H04; H04L; H04L9/00; H04L9/06; H04L9/065; H04L9/0656; H04L9/12; H04L2209/00; H04L2209/12; H04L2209/125
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
94 words
A code system for digital data representing a set of characters comprising: means for receiving a first digital word representative of one of said characters, means for randomly generating a digital key word from a predetermined set of digital key words, a memory storing digital representations of all of said characters grouped in addressable subsets according to the generated first digital word and the generated digital key word, said memory responsive to said first digital word and said digital key word for outputting a corresponding one of said digital representations stored in said memory.
Claim 2
Dependent Claim
94 words
A code system for digital data representing a set of characters comprising: means for receiving a first digital word representative of one of said characters, means for randomly generating a digital key word from a predetermined set of digital key words, a memory storing digital representations of all of said characters grouped in addressable subsets according to the generated first digital word and the generated digital key word, said memory responsive to said first digital word and said digital key word for outputting a corresponding one of said digital representations stored in said memory.
Claim 3
Dependent Claim
28 words
The code system of claim 1 wherein said first digital word comprises a plain text character and said corresponding one of said digital representations comprises an encoded character.
Claim 4
Dependent Claim
28 words
The code system of claim 1 wherein said first digital word comprises an encoded character and said corresponding one of said digital representations comprises a plain text character.
Claim 5
Dependent Claim
28 words
The code system of claim 1 wherein said digitial representations of said characters are grouped in columns and rows corresponding to generated first words and generated key words.
Claim 6
Dependent Claim
22 words
The code system of claim 1 wherein said digital representations of said characters are grouped in accordance with a predetermined ciphering algorithm.
Claim 7
Dependent Claim
22 words
The code system of claim 1 wherein said digital representations of said characters stored in said memory are represented in octal form.
Claim 8
Dependent Claim
112 words
An encoding system for digital data representing a set of characters comprising: means for receiving a clear text digital word representative of one of said characters, means for randomly generating a digital key word, a read only memory storing enciphered digital representations of all of said characters grouped in addressable subsets according to the generated clear text digital word and the generated digital key word, means responsive to said clear text digital word and said digital key word for generating an address representative of one of said enciphered digital representations stored in said read only memory, and means for generating an enciphered output comprising said addressed one of said enciphered digital representations.
Claim 9
Dependent Claim
112 words
An encoding system for digital data representing a set of characters comprising: means for receiving a clear text digital word representative of one of said characters, means for randomly generating a digital key word, a read only memory storing enciphered digital representations of all of said characters grouped in addressable subsets according to the generated clear text digital word and the generated digital key word, means responsive to said clear text digital word and said digital key word for generating an address representative of one of said enciphered digital representations stored in said read only memory, and means for generating an enciphered output comprising said addressed one of said enciphered digital representations.
Claim 10
Dependent Claim
19 words
The encoding system of claim 7 wherein said enciphered representations stored in said memory are represented in octal form.
Claim 11
Dependent Claim
28 words
The encoding system of claim 7 wherein predetermined ones of said set of characters are designated as forbidden characters and are not stored in said read only memory.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-02-19 | 1982-08-21 | 1983-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-02-19 | 1986-08-21 | 1987-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-02-19 | 1990-08-21 | 1991-02-20 | $7700.00 | Window Closed / Lapsed |