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US4751733A
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Substitution permutation enciphering device
Assignee: Thales SA
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Filing: 1986-05-14
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Granted: 1988-06-14
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Expires: 2006-05-14
Abstract
Abstract A substitution-permutation enciphering device. This device, adapted for transforming a binary word into another binary word, by a succession of substitutions and permutations, under the control of a key, is such that the substitution operations are performed by means of programmable or reprogrammable memories addressed by all or part of the word to undergo substitution, and by all or part of the key or of the parts of the key applied successively.
Inventors
- 👤 Bernard Delayaye
- 👤 Alain Lebret
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:04
CPC Classifications
H; H04; H04L; H04L9/00; H04L9/06; H04L9/0618; H04L9/0631; H04L2209/00; H04L2209/12
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
132 words
A substitution-permutation enciphering device for transforming an input binary word into another binary word by a succession of permutations and substitutions under control of a key, including: substitution memory means for effecting said substitutions, said substitution memory means storing plural sets of substitution tables, each set corresponding to a given key value, first addressing means for addressing said substitution memory means by at least some part of a word undergoing substitution and by at least some part of said key for selecting among said sets of substitution tables, means storing an auxiliary key, and second means for addressing said substitution memory means by said auxiliary key for selecting a single substitution table from that set selected by application of at least some part of said key applied to said first addressing means.
Claim 2
Dependent Claim
132 words
A substitution-permutation enciphering device for transforming an input binary word into another binary word by a succession of permutations and substitutions under control of a key, including: substitution memory means for effecting said substitutions, said substitution memory means storing plural sets of substitution tables, each set corresponding to a given key value, first addressing means for addressing said substitution memory means by at least some part of a word undergoing substitution and by at least some part of said key for selecting among said sets of substitution tables, means storing an auxiliary key, and second means for addressing said substitution memory means by said auxiliary key for selecting a single substitution table from that set selected by application of at least some part of said key applied to said first addressing means.
Claim 3
Dependent Claim
40 words
The device as claimed in claim 1, wherein each substitution memory means stores for a given value of the key two substitution tables, one giving a first substitution algorithm, and a second storing an inverse of said first substitution algorithm.
Claim 4
Dependent Claim
108 words
A device as recited in claim 1 which is designed for binary words of a given number of bits but which is usable with input binary words of less than said given number of bits, said device further including: input means for concatenating said input binary word of less than said given number of bits with one or more binary zero bits to produce a modified binary word of said given number of bits, initial and final permutation means for ensuring that bit positions containing said one or more binary zero bits in said modified binary word are identical with corresponding bit positions in said another binary word.
Claim 5
Dependent Claim
28 words
The device as claimed in claim 1, wherein said first addressing means applies the whole of the key several times, during several successive iterations of substitutions and permutations.
Claim 6
Dependent Claim
23 words
The device as claimed in claim 4, wherein said successive iterations of application of said key by said first addressing means are symmetrical.
Claim 7
Dependent Claim
52 words
The device as claimed in claim 1, wherein the input binary word is divided into groups of binary elements which device further includes permutation means including conductive wiring arranged to ensure homogeneous distribution of all of the binary elements of an input group over all output groups of said another binary word.
Claim 8
Dependent Claim
12 words
The device as claimed in claim 6, wherein said wiring is reversible.
Claim 9
Dependent Claim
20 words
The device as claimed in claim 1, wherein the substitution tables of said substitution memories are generated in random fashion.
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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) | 1991-06-14 | 1991-12-14 | 1992-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-14 | 1995-12-14 | 1996-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-14 | 1999-12-14 | 2000-06-14 | $7700.00 | Window Closed / Lapsed |