Cryptographic system including a mixed radix number generator with chosen statistical artifacts

• US 8,320,557 B2
• Filed: 05/08/2008
• Issued: 11/27/2012
• Est. Priority Date: 05/08/2008
• Status: Active Grant

• Current Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: Michaels, Alan J., Chester, David B.
• Primary Examiner(s): Arani, Taghi
• Assistant Examiner(s): Rahman, Mahfuzur
• Application Number:
  US12/117,086
• Publication Number:
  US 20090279690A1
• Time in Patent Office: 1,664 Days
• Field of Search: 380/28
• US Class Current: 380/28
• CPC Class Codes: G06F 7/58 Random or pseudo-random number generators
• CPC Class Codes: G06F 7/584 using finite field arithmetic, e.g. using a linear feedback shift register
• CPC Class Codes: G06F 7/724 Finite field arithmetic for error detection or correction in general H03M13/00, in computers G06F11/10
• CPC Class Codes: H04L 9/0662 with particular pseudorandom sequence generator

Abstract

A cryptographic system (1000) is provided. The cryptographic system includes a data stream receiving means (DSRM), a number generator (NG), a mixed radix accumulator (MRA) and an encryptor. The DSRM (1002) receives a data stream (DS). The NG (702) generates a first number sequence (FNS) contained within a Galois Field GF[M]. The MRA (750) is configured to perform a first modification to a first number (FN) in FNS. The first modification involves summing the FN with a result of a modulo P operation performed on a second number in FNS that proceeds FN. The MRA is also configured to perform a second modification to FN utilizing a modulo P operation. The MRA is further configured to repeat the first and second modification for numbers in FNS to generate a second number sequence (SNS). The encryptor (1004) is configured to generate a modified data stream by combining SNS and DS.

Claims

1. A cryptographic system, comprising:

a data stream receiving circuit configured to receive an input data stream;

a number generator circuit configured to generate a first sequence of numbers contained within a punctured Galois field GF′

[M] in which at least one element of a plurality of elements comprising a Galois field GF[M], has been removed;

a mixed radix accumulator circuit electronically connected to said number generator circuit and configured to

(1) perform a first modification to a first number in said first sequence of numbers comprising summing said first number with a result of a first modulo P operation plus a fixed offset performed on a second number of said first sequence that proceeds said first number, where a value of M is mutually prime with respect to a value of P and all of a plurality of relatively prime factors of P including p₁, p₂, p₃ . . . , p_k,

(2) subsequent to said first modification, perform a second modification to said first number comprising a second modulo P operation, and

(3) repeating said first and second modification for a plurality of numbers comprising said first sequence of numbers to generate a second sequence of numbers;

a plurality of arithmetic operator circuits each configured to perform a third modification on said second sequence of numbers for simultaneously generating a plurality of output number sequences from said second sequence of numbers, said third modification comprising a plurality of modulo p operations simultaneously performed upon each number in said second sequence of numbers to generate said plurality of output number sequences, where p includes a plurality of values selected from a group comprising p₁, p₂, p₃, . . . , p_k; and

an encryptor circuit electronically connected to said data stream receiving circuit and said plurality of arithmetic operator circuits, said encryptor circuit configured to generate a modified data stream by incorporating or combining at least one of said plurality of output number sequences with said input data stream.

2. The cryptographic system according to claim 1, wherein said number generator circuit comprises a pseudo-random number generator configured to generate a pseudo-random sequence of numbers containing statistical artifacts relating to said generation of said first sequence of numbers, and wherein said statistical artifact is eliminated by said mixed radix accumulator circuit.

3. The cryptographic system according to claim 1, wherein said number generator circuit is configured to exhaustively produce said first sequence of numbers by using a mapping which is periodically repeated.

4. The cryptographic system according to claim 3, wherein said mapping includes a combination of an additive mapping and a multiplicative mapping.

5. The cryptographic system according to claim 4, wherein said additive mapping and said multiplicative mapping in combination include repeated computations of an irreducible polynomial over said Galois field GF[M].

6. The cryptographic system according to claim 1, wherein said second number precedes said first number by one position.

7. The cryptographic system according to claim 1, wherein said second number precedes said first number by N positions, where N is greater than 1.

8. The cryptographic system according to claim 1, wherein said first sequence of numbers is limited to a finite number of elements M defined by said Galois field GF[M], said second sequence of numbers has statistical artifacts that are evenly distributed over a plurality of equivalence classes of said Galois field GF[P], and wherein said plurality of equivalence classes include an equivalence class for each integer 0, 1, . . . , P−

1.

9. The cryptographic system according to claim 1, wherein said first sequence is operated upon by a filter structure configured to perform calculations inside a Galois field of equal size to the second sequence.

10. The cryptographic system according to claim 1, wherein said encryptor circuit includes at least one of a multiplier, an adder, a digital logic device and a feedback mechanism.

11. The cryptographic system according to claim 1, wherein said encryptor circuit is configured to perform a standard multiplication operation, a multiplication in a Galois extension field operation, an addition modulo q operation, a subtraction modulo q operation or a bitwise logic operation.

12. The cryptographic system according to claim 1, further comprising a second number generator circuit and a second mixed radix accumulator circuit configured in combination to generate a decryption sequence.

13. The cryptographic system according to claim 12, further comprising a decryptor circuit coupled to said second mixed radix accumulator circuit, said decryptor circuit configured to produce decrypted data by performing a decryption method utilizing said modified data stream and said decryption sequence.

14. A cryptographic system, comprising:

a data stream generating circuit configured to generate an input data stream including a first sequence of numbers with a known non-uniform probability distribution and contained within a punctured Galois field GF′

[M] in which at least one element of a plurality of elements comprising a Galois field GF[M], has been removed;

a mixed radix accumulator circuit electronically connected to said data stream generating circuit and configured to

(1) perform a first modification to a first number in said first sequence of numbers comprising summing said first number with a result of a modulo P operation plus a fixed offset performed on a second number of said first sequence that proceeds said first number, where a value of M is mutually prime with respect to a value of P and all of a plurality of relatively prime factors of P including p₁, p₂, p₃, . . . , p_k,

(2) subsequent to said first modification, perform a second modification to said first number comprising a modulo P operation, and

(3) repeating said first and second modifications for a plurality of numbers comprising said first sequence of numbers to generate a second sequence of numbers;

a plurality of arithmetic operator circuits each configured to perform a third modification on said second sequence of numbers for simultaneously generating a plurality of output number sequences from said second sequence of numbers, said third modification comprising a plurality of modulo p operations simultaneously performed upon each number in said second sequence of numbers to generate said plurality of output number sequences, where p includes a plurality of values selected from a group comprising p₁, p₂, p₃, . . . , p_k; and

a cryptographic circuit configured to combine at least one of said plurality of output number sequences with a data signal to encrypt or decrypt said data signal.

15. The cryptographic system according to claim 14, wherein P is greater than M, P is equal to M, or P is a fixed value less than M.

16. The cryptographic system according to claim 14, wherein P is a time-varying value constrained to values greater than M, P is a time-varying value constrained to values equal to M, or P is a time-varying value less than M at a given point in time.

17. The cryptographic system according to claim 14, wherein said cryptographic circuit comprises a decryption device coupled to said plurality of arithmetic operator circuits and configured to produce decrypted data by performing a decryption method implementing a correlation-based mathematical structure.

18. The cryptographic system according to claim 17, wherein said correlation-based mathematical structure is a Hidden Markov Model.

19. A method for encrypting and decrypting an input data stream, comprising the steps of:

receiving, by at least one electronic circuit, an input data stream;

generating, by said electronic circuit, a first sequence of numbers contained within a punctured Galois field GF′

[M] in which at least one element of a plurality of elements comprising a Galois field GF[M], has been removed;

performing, by said electronic circuit, a first modification to a first number in said first sequence of numbers comprising summing said first number with a result of a first modulo P operation plus a fixed offset performed on a second number of said first sequence that proceeds said first number, where a value of M is relatively prime with respect to a value of P and all of a plurality of relatively prime factors of P including p₁, p₂, p₃, . . . , p_k;

performing, by said electronic circuit, a second modification subsequent to said first modification to said first number comprising a second modulo P operation;

repeating, by said electronic circuit, said first and second modifications for a plurality of numbers comprising said first sequence of numbers to generate a second sequence of numbers;

performing, by said electronic circuit, a third modification on said second sequence of numbers for simultaneously generating a plurality of output number sequences from said second sequence of numbers; and

generating, by said electronic circuit, a modified data stream by combining at least one of said plurality of output number sequences with said input data stream;

wherein said third modification comprises a plurality of modulo p operations simultaneously performed upon each number in said second sequence of numbers to generate said plurality of output number sequences, where p includes a plurality of values selected from a group comprising p₁, p₂, p₃, . . . , p_k.

20. The method according to claim 19, wherein said generating step further comprises performing a standard multiplication operation, a multiplication in a Galois extension field, an addition modulo q operation, a subtraction modulo q operation, or a bitwise logic operation.

21. The method according to claim 19, further comprising generating, by said electronic circuit, a decryption sequence, wherein said decryption sequence is a random number sequence having chosen statistical artifacts over all equivalence classes of a Galois Field GF[P].

22. The method according to claim 21, further comprising generating, by said electronic circuit, a decrypted data stream by performing a decryption method utilizing said modified data stream and said decryption sequence.