Cryptographic communication process and apparatus

• US 6,266,417 B1
• Filed: 02/17/2000
• Issued: 07/24/2001
• Est. Priority Date: 07/01/1998
• Status: Expired due to Fees

• Current Assignee: TecSec, Incorporated
• Original Assignee: TecSec, Incorporated
• Inventors: Wack, C. Jay, Scheidt, Edward M.
• Primary Examiner(s): Peeso, Thomas R.
• Assistant Examiner(s): JACK, TODD M
• Application Number:
  US09/506,016
• Time in Patent Office: 523 Days
• Field of Search: 380/28, 380/255, 380/29
• US Class Current: 380/255
• CPC Class Codes: H04L 9/0631 Substitution permutation network [SPN], i.e. cipher composed of a number of stages or rounds each involving linear and nonlinear transformations, e.g. AES algorithms
• CPC Class Codes: H04L 9/0637 Modes of operation, e.g. cipher block chaining [CBC], electronic codebook [ECB] or Galois/counter mode [GCM]
• CPC Class Codes: H04L 9/08 Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords network architectures or network communication protocols for supporting key management in a packet data network H04L63/06

Abstract

A communication system, which includes an origination space, a communications channel, and a destination space associated with the origination space via the communications channel. The origination space includes an encryption engine for generating an output symbol O_t based on an input symbol I_t and means for receiving an encrypt key, an encrypt text/key relation, and the input symbol. The destination space includes a decryption engine for generating a decrypted symbol I′_t based on the output symbol received from the origination space via the communications channel and means for receiving a decrypt key and a decrypt text/key relation. The encrypt text/key relation controls the encryption engine such that O_t=α_N(t)+π_N[α_N−1(t)+π_N−1[α_N−2(t)+ . . . +π₂[α₁(t)+π₁[I_t+α₀(t)]] . . . ]], mod W, where α_N, α_N−1, . . . , α₁, α₀ are N+1 additive transformations defined by the encrypt key, where π_N, π_N−1, . . . , π₂, π₀ are N permutations defined by the encrypt key, and where W represents the number of possibilities for each permutation defined by the encrypt key. The decrypt text/key relation controls the decryption engine such that I′_t=π₁⁻¹[π₂⁻¹[π₃⁻¹ . . . [π_N−1⁻¹[π_N⁻¹[O_t−α′_N(t)]−α′_N−1(t)]− . . . −α′₃(t)]−α′₂(t)]−α′₁(t)]−α′₀(t), mod W, where is π_i⁻¹ is defined by the decrypt key as the inverse of the permutation π_i, where α′_N, α′_N−1, . . . , α′₁, α′₀ are N+1 additive transformations defined by the decrypt key, and where W represents the number of possibilities for each inverse permutation defined by the decrypt key.

Claims

1. A communication system, comprising:

a) an origination space;

b) a communications channel; and

c) a destination space associated with the origination space via the communications channel;

d) wherein the origination space includes;

1) an encryption engine for generating an output symbol O_t based on an input symbol I_t; and

2) means for receiving an encrypt key, an encrypt text/key relation, and the input symbol;

e) wherein the destination space includes;

1) a decryption engine for generating a decrypted symbol I′

_t based on the output symbol received from the origination space via the communications channel; and

2) means for receiving a decrypt key and a decrypt text/key relation;

f) wherein the encrypt text/key relation controls the encryption engine such that O_t=α

_N(t)+π

_N[α

<sub>N−

1</sub>(t)+π

<sub>N−

1</sub>[α

<sub>N−

2</sub>(t)+ . . . +π

₂[α

₁(t)+π

₁[I_t+α

₀(t))]] . . . ]], mod W, where α

_N, α

<sub>N−

1</sub>, . . . , α

₁, α

₀ are N+1 additive transformations defined by the encrypt key, where π

_N, π

<sub>N−

1</sub>, . . . π

₂, π

₀ are N permutations defined by the encrypt key, and where W represents the number of possibilities for each permutation defined by the encrypt key; and

g) wherein the decrypt text/key relation controls the decryption engine such that I′

_t=π

₁<sup>−

1</sup>[π

₂<sup>−

1</sup>[π

₃<sup>−

1</sup> . . . [π

<sub>N−

1</sub><sup>−

1</sup>[π

_N<sup>−

1</sup>[O_t−

α

′

_N(t)]−

α

<sub>N−

1</sub>(t)]−

. . . −

α

′

₃(t)]−

α

′

₂(t)]−

α

′

₁(t)]−

α

′

₀(t), mod W, where π

_i<sup>−

1</sup> is defined by the decrypt key as the inverse of the permutation π

_i, where α

′

_N, α

′

<sub>N−

1</sub>, . . . , α

′

₁, α

′

₀ are N+1 additive transformations defined by the decrypt key, and where W represents the number of possibilities for each inverse permutation defined by the decrypt key.

2. The communication system of claim 1, wherein the encryption engine further includes W look-up tables for storing each of the possible W sets of permutations.

3. The communication system of claim 1, wherein the encryption engine further includes M<

W look-up tables for storing M available sets of the possible W sets of permutations.

4. The communication system of claim 1, wherein the encryption engine further includes N<

M<

W look-up tables for storing N sets of permutations preselected from M available sets of the possible W sets of permutations.

5. The communication system of claim 1, wherein α

(t) is a step function.

6. A communication system, comprising:

a) an origination space;

b) a communications channel; and

c) a destination space associated with the origination space via the communications channel;

d) wherein the origination space includes;

1) means for receiving an input symbol I_t, an encrypt key, and an encrypt text/key relation; and

2) an encryption engine, controllable by the encrypt text/key relation for generating an output symbol O_t based on the input symbol, such that O_t=α

_N(t)+π

_N[α

<sub>N−

1</sub>(t)+π

<sub>N−

1</sub>[α

<sub>N−

2</sub>(t)+ . . . +π

₂[α

₁(t)+π

₁[I_t+α

₀(t)]] . . . ]], mod W, where α

_N, α

<sub>N−

1</sub>, . . . , α

₁, α

₀ are N+1 additive transformations defined by the encrypt key, where π

_N, π

<sub>N−

1</sub>, . . . , π

₂, π

₀ are N permutations defined by the encrypt key, and where W represents the number of possibilities for each permutation defined by the encrypt key; and

e) wherein the destination space includes;

1) means for receiving a decrypt key and a decrypt text/key relation; and

2) a decryption engine, controllable for generating a decrypted symbol I′

_t based on the output symbol received from the origination space via the communications channel, such that I′

_t=π

₁<sup>−

1</sup>[π

₂<sup>−

1</sup>[π

₃<sup>−

1</sup> . . . [π

<sub>N−

1</sub><sup>−

1</sup>[π

_N<sup>−

1</sup>[O_t−

α

′

_N(t)]−

α

′

<sub>N−

1</sub>(t)]−

. . . −

α

′

₃(t)]−

α

′

₂(t)]−

α

′

₁(t)]−

α

′

₀(t), mod W, where π

_i<sup>−

1</sup> is defined by the decrypt key as the inverse of the permutation π

_i, where α

′

_N, α

′

<sub>N−

1</sub>, . . . , α

′

₁, α

′

₀ are N+1 additive transformations defined by the decrypt key, and where W represents the number of possibilities for each inverse permutation defined by the decrypt key.

7. The communication system of claim 6, wherein the encryption engine further includes W look-up tables for storing each of the possible W sets of permutations.

8. The communication system of claim 6, wherein the encryption engine further includes M<

W look-up tables for storing M available sets of the possible W sets of permutations.

9. The communication system of claim 6, wherein the encryption engine further includes N<

M<

W look-up tables for storing N sets of permutations preselected from M available sets of the possible W sets of permutations.

10. The communication system of claim 6, wherein α

(t) is a step function.

11. A communication system, comprising:

a) a first computer;

b) a communications channel; and

c) a second computer coupled with the first computer via the communications channel;

d) wherein the first computer includes;

1) a symbol input port for receiving an input symbol I_t;

2) an encrypt key input port for receiving an encrypt key;

3) a first memory, for storing an encrypt text/key relation; and

4) a first microprocessor for generating an output symbol O_t based on the input symbol, controlled by the encrypt text/key relation such that O_t=α

_N(t)+π

_N[α

<sub>N−

1</sub>(t)+π

<sub>N−

1</sub>[α

<sub>N−

2</sub>(t)+ . . . +π

₂[α

₁(t)+π

₁[I_t+α

₀(t)]] . . . ]], mod W, where α

_N, α

<sub>N−

1</sub>, . . . , α

₁, α

₀ are N+1 additive transformations defined by the encrypt key, where π

_N, π

<sub>N−

1</sub>, . . . π

₂, π

₀ are N permutations defined by the encrypt key, and where W represents the number of possibilities for each permutation defined by the encrypt key; and

e) wherein the second computer includes;

1) a decrypt key input port for receiving a decrypt key;

2) a second memory, for storing a decrypt text/key relation; and

3) a second microprocessor for generating a decrypted symbol I′

_t based on the output symbol received from the origination space via the communications channel, controlled by the decrypt text/key relation such that I′

_t=π

₁<sup>−

1</sup>[π

₂<sup>−

1</sup>[π

₃<sup>−

1</sup> . . . [π

<sub>N−

1</sub><sup>−

1</sup>[π

_N<sup>−

1</sup>[O_t−

α

′

_N(t)]−

α

′

<sub>N−

1</sub>(t)]−

. . . −

α

′

₃(t)]−

α

′

₂(t)]−

α

′

₁(t)]−

α

′

₀(t), mod W, where π

_i<sup>−

1</sup> is defined by the decrypt key as the inverse of the permutation π

_i, where α

′

_N, α

′

<sub>N−

1</sub>, . . . , α

′

₁, α

′

₀ are N+1 additive transformations defined by the decrypt key, and where W represents the number of possibilities for each inverse permutation defined by the decrypt key.

12. The communication system of claim 11, wherein the first computer further includes W look-up tables for storing each of the possible W sets of permutations.

13. The communication system of claim 11, wherein the first computer further includes M<

W look-up tables for storing M available sets of the possible W sets of permutations.

14. The communication system of claim 11, wherein the first computer further includes N<

M<

W look-up tables for storing N sets of permutations preselected from M available sets of the possible W sets of permutations.

15. The communication system of claim 11, wherein α

(t) is a step function.

16. A process for communication between an origination space and a destination space, comprising:

a) receiving an input symbol I_t at the origination space;

b) generating an output symbol O_t based on the input symbol, such that O_t=α

_N(t)+π

_N[α

<sub>N−

1</sub>(t)+π

<sub>N−

1</sub>[α

<sub>N−

2</sub>(t)+ . . . +π

₂[α

₁(t)+π

₁[I_t+α

₀(t)]] . . . ]], mod W, where α

_N, α

<sub>N−

1</sub>, . . . , α

₁, α

₀ are N+1 predetermined additive transformations, where π

_N, π

<sub>N−

1</sub>, . . . , π

₂, π

₀ are N predetermined permutations, and where W represents the number of possibilities for each permutation;

c) receiving the output symbol at the destination space; and

d) generating a decrypted symbol I′

_t based on the received output symbol, such that I′

_t=π

₁<sup>−

1</sup>[π

₂<sup>−

1</sup>[π

₃<sup>−

1</sup> . . . [π

<sub>N−

1</sub><sup>−

1</sup>[π

_N<sup>−

1</sup>[O_t−

α

′

_N(t)]−

α

′

<sub>N−

1</sub>(t)]−

. . . −

α

′

₃(t)]−

α

′

₂(t)]−

α

′

₁(t)]−

α

′

₀(t), mod W, where π

_i<sup>−

1</sup> is an inverse of the predetermined permutation π

_i, where α

′

_N, α

′

<sub>N−

1</sub>, . . . , α

′

₁, α

′

₀ are N+1 predetermined additive transformations, and where W represents the number of possibilities for each inverse permutation.

17. The process of claim 16, further including retrieving the possible W sets of permutations from W look-up tables, prior to generating the output symbol.

18. The process of claim 16, further including retrieving M available sets of the possible W sets of permutations from M<

W look-up tables, prior to generating the output symbol.

19. The process of claim 16, further including retrieving N sets of permutations preselected from M available sets of the possible W sets of permutations from N<

M<

W look-up tables, prior to generating the output symbol.

20. The process of claim 16, wherein α

(t) is a step function.

21. A storage medium, comprising:

interface means, and

means for controlling a microprocessor, via the interface means, to produce an output symbol O_t, such that O_t=α

_N(t)+π

_N[α

<sub>N−

1</sub>(t)+π

<sub>N−

1</sub>[α

<sub>N−

2</sub>(t)+ . . . +π

₂[α

₁(t)+π

₁[I_t+α

₀(t)]] . . . ]], mod W,

where I_t is an input symbol, α

_N, α

<sub>N−

1</sub>, . . . , α

₁, α

₀ are N+1 additive transformations defined by a key, π

_N, π

<sub>N−

1</sub>, . . . , π

₂, π

₀ are N permutations defined by the key, and W represents the number of possibilities for each permutation defined by the key.

22. The storage medium of claim 21, wherein α

(t) is a step function.

23. A storage medium, comprising:

interface means, and

means for controlling a microprocessor, via the interface means, to produce a generated symbol I′

_t, such that I′

_t=π

₁<sup>−

1</sup>[π

₂<sup>−

1</sup>[π

₃<sup>−

1</sup> . . . [π

<sub>N−

1</sub><sup>−

1</sup>[π

_N<sup>−

1</sup>[O_t−

α

_N(t)]−

α

<sub>N−

1</sub>(t)]−

. . . −

α

₃(t)]−

α

₂(t)]−

α

₁(t)]−

α

₀(t), mod W,

where O_t is a received symbol, α

_N, α

<sub>N−

1</sub>, . . . , α

₁, α

₀ are N+1 additive transformations defined by a key, π

₁<sup>−

1</sup>, π

₂<sup>−

1</sup>, π

₃<sup>−

1</sup> . . . , π

<sub>N−

1</sub><sup>−

1</sup>, π

_N<sup>−

1</sup> are N inverse permutations defined by the key, and W represents the number of possibilities for each inverse permutation defined by the key.

24. The storage medium of claim 23, wherein α

(t) is a step function.