Secure self learning system

• US 5,686,904 A
• Filed: 09/30/1994
• Issued: 11/11/1997
• Est. Priority Date: 05/29/1991
• 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:
  US08/313,613
• Time in Patent Office: 1,138 Days
• Field of Search: 340/825.3, 340/825.31, 340/825.34, 340/825.56, 340/825.69, 340/825.72, 235/382.5, 307/10.2, 307/10.5, 361/172, 70/256, 380/23, 380/45, 380/30
• US Class Current: 340/5.23
• CPC Class Codes: G07C 2009/0023 with encription of the transmittted data signal
• CPC Class Codes: G07C 2009/00412 the transmitted data signal being encrypted
• CPC Class Codes: G07C 2009/00769 with data transmission performed by wireless means
• CPC Class Codes: G07C 2009/00928 for garage doors
• CPC Class Codes: G07C 2209/06 Involving synchronization or resynchronization between transmitter and receiver; reordering of codes
• CPC Class Codes: G07C 9/00182 operated with unidirectional data transmission between data carrier and locks
• CPC Class Codes: G07C 9/00817 where the code of the lock can be programmed
• CPC Class Codes: H04L 2209/34 Encoding or coding, e.g. Huffman coding or error correction
• CPC Class Codes: H04L 2209/80 Wireless
• CPC Class Codes: H04L 2209/84 Vehicles
• CPC Class Codes: H04L 9/0838 Key agreement, i.e. key establishment technique in which a shared key is derived by parties as a function of information contributed by, or associated with, each of these network architectures or network communication protocols for key exchange in a packet data network H04L63/061
• CPC Class Codes: H04L 9/0869 involving random numbers or seeds

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, second information, and a key generation routine;

storing the second information in the first station;

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

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

receiving the second information by the second station during learning; and

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, and the key generation routine.

2. 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.

3. A method according to claim 2, wherein:

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

4. A method according to claim 1, wherein:

the step of storing the second information comprises storing the second information which is a serial number, and

the step of transmitting the second information comprising transmitting the second information which is the serial number.

5. A method according to claim 1, wherein:

the step of storing the second information comprises storing the second information which is a seed, and

the step of transmitting the second information comprising transmitting the second information which is the seed.

6. A method according to claim 1, wherein:

the step of storing the second information comprises storing the second information which is a randomly generated seed, and

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

7. A method according to claim 1, wherein:

the step of storing the second information comprises storing the second information which is information derived from applying the key and an algorithm to an input value, and

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

8. 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.

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

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

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.

10. A method according to claim 9, 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;

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

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

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;

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

executing a function which corresponds to the encoded information which has been decoded, only when the step of 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.

11. A method according to claim 10, 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.

12. 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.

13. 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, second information, and a key generation routine;

a memory which stores the second information in the first station;

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; and

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, and the key generation routine.

14. A system according to claim 13, wherein:

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

15. A system according to claim 14, wherein:

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

16. A system according to claim 13, wherein:

the memory which stores the second information stores 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.

17. A system according to claim 13, wherein:

the memory which stores the second information stores 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.

18. A system according to claim 13, wherein:

the memory which stores the second information stores 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.

19. A system according to claim 13, wherein:

the memory which stores the second information stores 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.

20. A system according to claim 13, 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.

21. A system according to claim 13, 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.

22. A system according to claim 20, 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.

23. A system according to claim 20, 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.

24. A system according to claim 13, 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.