Secure self learning system

• US 6,191,701 B1
• Filed: 08/25/1995
• Issued: 02/20/2001
• Est. Priority Date: 08/25/1995
• Status: Expired due to Term

• Current Assignee: Microchip Technology Incorporated
• Original Assignee: Microchip Technology Incorporated
• Inventors: Bruwer, Frederick Johannes
• Primary Examiner(s): Holloway, III, Edwin C.
• Application Number:
  US08/519,612
• Time in Patent Office: 2,006 Days
• Field of Search: 340/825.3, 340/825.31, 340/825.34, 340/825.56, 380/45, 380/30, 380/21, 380/283, 380/284, 380/285, 361/172, 235/380
• US Class Current: 340/5.22
• CPC Class Codes: G07C 2009/00412 the transmitted data signal being encrypted
• CPC Class Codes: G07C 2009/00476 dynamically
• CPC Class Codes: G07C 2009/00507 keyless data carrier having more than one function
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 2009/00888 programming by learning
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks
• CPC Class Codes: G08C 19/28 using pulse code

Abstract

A method and system for the remote control of devices having a secure self learn capability. The system includes an encoder and a decoder, the encoder encoding variable information including a user key using a non-linear algorithm to produce an encoded value transmitted to the decoder, the decoder decoding the value using the same algorithm. In a learning mode a new encoder is to be added to the system. The new encoder produces an encoded value using a key generation seed. The decoder, upon receiving the encoded key generation seed, produces a decoding key based upon the decoded key generation seed. The decoding key is stored in the decoder memory allowing valid recognition of the new encoder in a secure manner.

Claims

1. A method of determining a key to be used for encrypting and decrypting information transmitted between two stations, comprising the steps of:

storing a key in a first station during manufacturing, the key being generated using first information not used by said first station, second information, and a key generation routine;

storing the key generation routine and the first information in a second station during manufacturing;

transmitting the second information from the first station to the second station during learning;

receiving the second information by the second station during learning;

calculating, during learning, a key in the second station using the second information which has been received, the first information which has been stored in said second station during manufacturing, and the key generation routine; and

selectively stopping transmitting the second information.

2. A method as recited in claim 1, wherein the step of selectively stopping comprises:

permanently stopping transmitting the second information.

3. A method as recited in claim 1, wherein the step of selectively stopping comprises:

stopping transmitting the second information after the second information is transmitted a predetermined number of times.

4. A method as recited in claim 3, wherein the step of selectively stopping comprises:

permanently stopping transmitting the second information.

5. A method as recited in claim 1, wherein:

said second station is a remote encoder device; and

the step of selectively stopping comprises activating a command to stop the transmitting of the second information.

6. A method as recited in claim 5, comprising:

activating the command to permanently stop the transmitting of the second information.

7. A method according to claim 1, wherein:

the first station is a transmitter and operates during the learning without performing a step of receiving information from the second station.

8. A method according to claim 7, wherein:

the second station is a receiver and operates during the learning without performing a step of transmitting to the first station.

9. A method according to claim 1, comprising:

storing in said first station the second information which is a serial number, wherein the step of transmitting the second information comprises transmitting the second information which is the serial number.

10. A method according to claim 1, comprising:

storing in said first station the second information which is a seed, and wherein the step of transmitting the second information comprises transmitting the second information which is the seed.

11. A method according to claim 1, comprising:

storing in said first station the second information which is a randomly generated seed, and

wherein the step of transmitting the second information comprises transmitting the second information which is the randomly generated seed.

12. A method according to claim 1, comprising:

storing in said first station the second information which is information derived from applying the key and an algorithm to an input value, and

wherein the step of transmitting the second information comprises transmitting the second information which is the information derived from applying the key and the algorithm to an input value.

13. A method according to claim 1, wherein:

the step of storing the first information in the second station during manufacturing comprises storing the first information which is a manufacturer'"'"'s master key; and

the step of calculating the key in the second station uses the first information which is the manufacturer'"'"'s master key.

14. A method according to claim 1, further comprising the step of:

storing the second information during manufacturing;

storing third information, in the first station, which is different from the second information,

wherein the step of transmitting the second information further comprises transmitting the third information from the first station to the second station during learning, and wherein the step of receiving the second information comprises receiving and storing the third information during learning.

15. A method according to claim 14, further comprising, performed after the step of calculating the key in the second station, the steps of:

encoding information by the first station using the key stored therein;

the first station is a transmitter and operates during the learning without receiving information from the second station.

16. A method according to claim 14, further comprising the steps of:

comparing the third information which has been received with management information; and

verifying a validity of the third information when the comparing step determines that the information which has been received corresponds to the management information.

17. A method according to claim 1, further comprising the step of:

transmitting counter information from the first station to the second station, after the step of transmitting the second information;

receiving the counter information by the second station;

comparing the counter information which has been received with counter information which has been previously stored in the second station; and

prohibiting the execution of a command by the second station when the counter information which has been received is not successive to the counter information which has been previously stored.

18. A system for determining a key to be used for encrypting and decrypting information transmitted between two stations, comprising:

a memory which stores a key in a first station during manufacturing, the key being generated using first information not used by said first station, second information, and a key generation routine;

a memory which stores a key generation routine and the first information in a second station during manufacturing;

means for transmitting the second information from first station to the second station during learning;

means for receiving the second information by the second station during learning;

means for calculating, during learning, a key in the second station using the second information which has been received, the first information which has been stored during manufacturing in said second station, and the key generation routine; and

means for selectively stopping transmission of the second information after a successful learning operation.

19. A system according to claim 18, wherein:

the first station is a transmitter and operates during the learning without receiving information from the second station.

20. A system according to claim 19, wherein:

the second station is a receiver and operates during the learning without transmitting to the first station.

21. A system according to claim 18, comprising:

a memory storing the second information which is a serial number, and the means for transmitting the second information comprises means for transmitting the second information which is the serial number.

22. A system according to claim 18, comprising:

a memory storing the second information which is a seed, and

the means for transmitting the second information comprises means for transmitting the second information which is the seed.

23. A system according to claim 18, comprising:

a memory storing the second information which is a randomly generated seed, and

the means for transmitting the second information comprises means for transmitting the second information which is the randomly generated seed.

24. A system according to claim 18, comprising:

a memory storing the second information which is information derived from applying the key and an algorithm to an input value, and

the means for transmitting the second information comprises transmitting the second information which is the information derived from applying the key and an algorithm to an input value.

25. A system according to claim 18, wherein:

the memory which stores the first information in the second station during manufacturing stores the first information which is a manufacturer'"'"'s master key; and

the means for calculating the key in the second station uses the first information which is the manufacturer'"'"'s master key.

26. A system according to claim 18, further comprising:

a memory, in the first station, which stores third information which is different from the second information stored during manufacturing,

wherein the means for transmitting the second information further comprises means for transmitting the third information from the first station to the second station during learning, and

wherein the means for receiving the second information comprises means for receiving and a memory which stores the third information during learning.

27. A system according to claim 26, further comprising:

means for encoding information by the first station using the key stored therein;

means for transmitting the third information and the information encoded by the first station;

means for receiving, by the second station, the third information and the information encoded by the first station;

means for comparing, by the second station, the third information which was transmitted with the information encoded by the first station with the third information stored during learning;

means for decoding, by the second station, the encoded information; and

means for executing a function which corresponds to the encoded information which has been decoded, only when the means for comparing determines that the third information which was transmitted with the information encoded by the first station corresponds to the third information stored during learning.

28. A system according to claim 26, further comprising:

means for comparing the third information which has been received with management information; and

means for verifying a validity of the third information when the means for comparing determines that the information which has been received corresponds to the management information.

29. A system according to claim 18, further comprising:

means for transmitting counter information from the first station to the second station, after transmitting the second information;

means for receiving the counter information by the second station;

means for comparing the counter information which has been received with counter information which has been previously stored in the second station; and

means for prohibiting the execution of a command by the second station when the counter information which has been received is not successive to the counter information which has been previously stored.

30. A system as recited in claim 18, wherein the means for selectively stopping comprises:

means for permanently stopping transmitting the second information.

31. A system as recited in claim 30, wherein the means for selectively stopping comprises one of:

a switch,

a switch and a counter, and

a controller, counter and switch.

32. A system as recited in claim 18, wherein the means for selective stopping comprises:

means for stopping transmitting the second information after the second information is transmitted a predetermined number of times.

33. A system as recited in claim 32, wherein the means for selectively stopping comprises:

means for permanently stopping transmitting the second information.

34. A method as recited in claim 18, wherein:

said second station is a remote encoder device; and

the means for selectively stopping comprises means for activating a command to stop the transmitting of the second information.

35. A system as recited in claim 34, comprising:

means for activating the command to permanently stop the transmitting of the second information.

36. A system as recited in claim 35, wherein the means for selectively

stopping comprises one of:

a switch,

a switch and a counter, and

a controller, counter and switch.