System and method for optimizing error detection to detect unauthorized modification of transmitted data

• US 20060120521A1
• Filed: 12/08/2004
• Published: 06/08/2006
• Est. Priority Date: 12/08/2004
• Status: Active Grant

• Current Assignee: Schweitzer Engineering Laboratories, Incorporated
• Original Assignee: Schweitzer Engineering Laboratories, Incorporated
• Inventors: Whitehead, David E., Risley, Allen D.
• Granted Patent: US 7,680,273 B2
• Time in Patent Office: Days
• US Class Current: 380/46
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 9/0662 with particular pseudorandom sequence generator
• CPC Class Codes: H04L 9/12 Transmitting and receiving encryption devices synchronised or initially set up in a particular manner
• CPC Class Codes: H04L 9/34 Bits, or blocks of bits, of the telegraphic message being interchanged in time for speech signals H04K1/06

Abstract

Disclosed is a system and method for optimizing error detection to detect unauthorized modification of transmitted data. The system includes an encrypting device and a decrypting device operatively coupled to the first encrypting device. The encrypting device is configured to re-order and encrypt a first data stream to form a second data stream, and the decrypting device is configured to re-order and decrypt the second data stream to form a third data stream substantially identical to the first data stream. Each of the encrypting and decrypting devices includes at least one pseudo-random number generator, a reversible function device responsive to a first pseudo-random number generator to cause data stream bits to be re-ordered, and a XOR function responsive to a second or the first pseudo-random number generator to cause either consecutive portions of the data stream bits to be encrypted or decrypted.

Claims

1. A system for optimizing error detection to detect unauthorized modification of transmitted data, the system comprising:

a first encrypting device configured to perform a re-ordering step and an encrypting step to a first data stream to form a second data stream; and

a first decrypting device operatively coupled to the first encrypting device, the first decrypting device configured to perform a re-ordering step and a decrypting step to the second data stream to form a third data stream substantially identical to the first data stream.

2. The system of claim 1, wherein the first encrypting device comprises:

a first pseudo-random number generator;

a second pseudo-random number generator;

a first reversible function device operatively coupled to and responsive to the first pseudo-random number generator to re-order the first data stream to form a re-ordered data stream; and

a first XOR function operatively coupled to and responsive to the second pseudo-random number generator to encrypt the re-ordered data stream to form the second data stream.

3. The system of claim 2, wherein the first decrypting device comprises:

a third pseudo-random number generator;

a fourth pseudo-random number generator;

a second XOR function operatively coupled to and responsive to the third pseudo-random number generator to decrypt the second stream to form a decrypted data stream; and

a second reversible function device operatively coupled to and responsive to the fourth pseudo-random number generator to re-order the decrypted data stream to form the third data stream.

4. The system of claim 3, wherein operation of the first pseudo-random number generator is synchronized to operation of the fourth pseudo-random number generator, and wherein operation of the second pseudo-random number generator is synchronized to operation of the third pseudo-random number generator.

5. The system of claim 3, wherein the first encrypting device further comprises a first microcontroller having a first microprocessor and a first memory operatively coupled to the first microprocessor, and wherein the decrypting device further comprises a second microcontroller having a second microprocessor and a second memory operatively coupled to the second microprocessor.

6. The system of claim 5, further comprising a second decrypting device operatively coupled to the first microcontroller, the first encrypting device and the second decrypting device and the first microcontroller adapted to form a first serial communication device.

7. The system of claim 6, further comprising a second encrypting device operatively coupled to the second microcontroller, the second encrypting device and the first decrypting device and the second microcontroller adapted to form a second serial communication device, the second serial communication device coupled to the first serial communication device via a communication network.

8. The system of claim 3, wherein the first reversible function device is configured to apply a first function to the first data stream to form the re-ordered data stream, wherein the second reversible function device is configured to apply a second function to the decrypted data stream to form the third data stream, and wherein application of the second function reverses a result from application of the first function.

9. The system of claim 8, wherein the first function comprises a random bit-rotation of at least one bit of a portion of the first data stream, the random bit-rotation based on at least one number generated by the first random number generator.

10. The system of claim 8, wherein the first function comprises a random bit-reordering of at least one bit of a portion of the first data stream, the random bit-reordering based on at least one number generated by the first random number generator.

11. The system of claim 1, wherein the first encrypting device comprises:

a first pseudo-random number generator;

a second pseudo-random number generator;

a first XOR function operatively coupled to and responsive to the first pseudo-random number generator to encrypt the first data stream to form an encrypted data stream; and

a first reversible function device operatively coupled to and responsive to the second pseudo-random number generator to re-order the encrypted data stream to form the second data stream.

12. The system of claim 11, wherein the first decrypting device comprises:

a third pseudo-random number generator;

a fourth pseudo-random number generator;

a second reversible function device operatively coupled to and responsive to the third pseudo-random number generator to re-order the second data stream to form a re-ordered data stream; and

a second XOR function operatively coupled to and responsive to the fourth pseudo-random number generator to decrypt the re-ordered data stream to form the third data stream.

13. The system of claim 12, further comprising:

a first microcontroller operatively coupled to the first encrypting device; and

a second decrypting device operatively coupled to the first microcontroller, the first encrypting device and the second decrypting device and the first microcontroller adapted to form a first serial communication device.

14. The system of claim 13, further comprising:

a second microcontroller operatively coupled to the first decrypting device; and

a second encrypting device operatively coupled to the second microcontroller, the second encrypting device and the first decrypting device and the second microcontroller adapted to form a second serial communication device, the second serial communication device operatively coupled to the first serial communication device via a communication network.

15. The system of claim 1, wherein the first encrypting device comprises:

a first pseudo-random number generator;

a first reversible function device operatively coupled to the first pseudo-random number generator and responsive to a first random number stream generated by the first pseudo-random number generator to re-order the first data stream to form a re-ordered data stream; and

a first XOR function operatively coupled to the first pseudo-random number generator and responsive to a second random number stream generated by the first pseudo-random number generator to encrypt the re-ordered data stream to form the second data stream.

16. The system of claim 15, wherein the first decrypting device comprises:

a second pseudo-random number generator;

a second XOR function operatively coupled to the second pseudo-random number generator and responsive to a third random number stream generated by the second pseudo-random number generator to decrypt the second data stream to form a decrypted data stream; and

a second reversible function device operatively coupled to the second pseudo-random number generator and responsive to a fourth random number stream generated by the second pseudo-random number generator to re-order the decrypted data stream to form the third data stream.

17. The system of claim 16, wherein the first encrypting device further comprises a first microcontroller having a first microprocessor and a first memory operatively coupled to the first microprocessor, and wherein the decrypting device further comprises a second microcontroller having a second microprocessor and a second memory operatively coupled to the second microprocessor.

18. The system of claim 17, further comprising a second decrypting device operatively coupled to the first microcontroller, the first encrypting device and the second decrypting device and the first microcontroller adapted to form a first serial communication device.

19. The system of claim 18, further comprising a second encrypting device operatively coupled to the second microcontroller, the second encrypting device and the first decrypting device and the second microcontroller adapted to form a second serial communication device, the second serial communication device coupled to the first serial communication device via a communication network.

20. The system of claim 16, wherein operation of the first pseudo-random number generator is synchronized to operation of the second pseudo-random number generator.

21. The system of claim 16, wherein the first reversible function device is configured to apply a first function to the first data stream to form the re-ordered data stream, wherein the second reversible function device is configured to apply a second function to the decrypted data stream to form the third data stream, and wherein application of the second function reverses a result from application of the first function.

22. The system of claim 21, wherein the first function comprises a random bit-rotation of at least one bit of a portion of the first data stream, the random bit-rotation based on at least one number generated by the first random number generator.

23. The system of claim 21, wherein the first function comprises a random bit-reordering of at least one bit of a portion of the first data stream, the random bit-reordering based on at least one number generated by the first random number generator.

24. A method for optimizing error detection to detect modification of data provided by an encrypting device to a decrypting device, the encrypting device including a first microcontroller having a first microprocessor and a first memory operatively coupled to the first microprocessor, the decrypting device including a second microcontroller having a second microprocessor and a second memory operatively coupled to the second microprocessor, the method comprising:

causing the encrypting device to perform a re-ordering step and perform an encrypting step to a first data stream to form a second data stream; and

causing the decrypting device to perform a decrypting step and a re-ordering step to the second data stream to form a third data stream substantially identical to the first data stream.

25. The method of claim 24, wherein causing a first data stream to be re-ordered and encrypted comprises:

causing a first reversible function device of the encrypting device to re-order the first data stream to form a re-ordered data stream; and

causing a first XOR function of the encrypting device to encrypt the re-ordered data stream to form the second data stream.

26. The method of claim 25, wherein the first reversible function device is coupled to a first pseudo-random number generator of the encrypting device and responsive to a first random number stream generated by the first pseudo-random number generator, and wherein the first XOR function is coupled to the first pseudo-random number generator and responsive to a second random number stream generated by the first pseudo-random number generator.

27. The method of claim 26, wherein causing the decrypting device to decrypt and re-order the second data stream comprises:

causing a second XOR function of the decrypting device to decrypt the second data stream to form a decrypted data stream; and

causing a second reversible function device of the decrypting device to re-order the decrypted data stream to form the third data stream.

28. The method of claim 27, wherein the second XOR function is coupled to a second pseudo-random number generator of the decrypting device and responsive to third random number stream generated by the second pseudo-random number generator, and wherein the second reversible function device is coupled to second pseudo-random number generator and responsive to a fourth random number stream generated by the second pseudo-random number generator.

29. The method of claim 28, wherein operation of the first pseudo-random number generator is synchronized to operation of the second pseudo-random number generator.

30. The method of claim 28, further comprising:

causing the first reversible function device to apply a first function to the first data stream to form the re-ordered data stream; and

causing the second reversible function device to apply a second function to the decrypted data stream to form the third data stream,

wherein application of the second function reverses application of the first function.

31. The method of claim 30, wherein the first function comprises a random bit-rotation of at least one bit of a portion of the first data stream, the random bit-rotation based on at least one number generated by the first random number generator.

32. The method of claim 30, wherein the first function comprises a random bit-reordering at least one bit of a portion of the first data stream, the random bit-reordering based on at least one number generated by the first random number generator.

33. The method of claim 24, wherein causing the first data stream to be re-ordered and encrypted comprises:

causing a first reversible function device of the encrypting device to re-order the first data stream to form a re-ordered data stream, the first reversible function device coupled to and responsive to a first pseudo-random number generator of the encrypting device; and

causing a first XOR function of the encrypting device to encrypt the re-ordered data stream to form the second data stream, the first XOR function coupled to and responsive to a second pseudo-random number generator of the encrypting device.

34. The method of claim 33, wherein causing the decrypting device to decrypt and re-order the second data stream comprises:

causing a second XOR function of the decrypting device to decrypt the second data stream to form a decrypted data stream, the second XOR function coupled to and responsive to a third pseudo-random number generator of the decrypting device; and

causing a second reversible function device of the decrypting device to re-order the decrypted data stream to form the third data stream, the second reversible function device coupled to and responsive to a fourth pseudo-random number generator of the encrypting device.

35. The method of claim 34, wherein operation of the first pseudo-random number generator is synchronized to operation of the fourth pseudo-random number generator, and wherein operation of the second pseudo-random number generator is synchronized to operation of the third pseudo-random number generator.

36. The method of claim 24, wherein causing the first data stream to be re-ordered and encrypted comprises:

causing a first XOR function of the encrypting device to encrypt the first data stream to form an encrypted data stream, the first XOR function coupled to and responsive to a first pseudo-random number generator of the encrypting device; and

causing a first reversible function device of the encrypting device to re-order the encrypted data stream to form the second data stream, the first reversible function device coupled to and responsive to a second pseudo-random number generator of the encrypting device.

37. The method of claim 36, wherein causing the decrypting device to decrypt and re-order the second data stream comprises:

causing a second reversible function device of the decrypting device to re-order the second data stream to form a re-ordered data stream, the second reversible function device coupled to and responsive to a third pseudo-random number generator of the encrypting device; and

causing a second XOR function of the decrypting device to decrypt the re-ordered data stream to form the third stream, the second XOR function coupled to and responsive to a fourth pseudo-random number generator of the decrypting device.