Communication system having a transmitter and a receiver that engage in reduced size encrypted data communication

• US 6,829,357 B1
• Filed: 12/14/1999
• Issued: 12/07/2004
• Est. Priority Date: 12/14/1999
• Status: Expired due to Fees

• Current Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Juzswik, David Leonard, Alrabady, Ansaf Ibrahem
• Primary Examiner(s): Meislahn, Douglas
• Application Number:
  US09/460,061
• Time in Patent Office: 1,820 Days
• Field of Search: 380/262, 380/260
• US Class Current: 380/262
• CPC Class Codes: H04L 2209/805 Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
• CPC Class Codes: H04L 2209/84 Vehicles
• CPC Class Codes: H04L 9/0656 Pseudorandom key sequence combined element-for-element with data sequence, e.g. one-time-pad [OTP] or Vernam's cipher

Abstract

A communication system (10) has a portion (28) of a transmitter controller (14) that provides a message package. An encryption portion (36) of the controller (14) encrypts a first fraction of the message package (e.g., a first portion of the message package and a first part of a second portion of the message package) using a second fraction of the message package (e.g., a second part of the second portion of the message package) as an encryption key. Transmitter components (32 and 34) output a signal (18) that conveys the encrypted first fraction of the message package. Receiver components (56 and 58) receive the signal (18). A decryption portion (60) of a receiver/controller unit (16) decrypts the signal using a decryption key, and reassembles the message package using the decryption key as the second fraction of the message package. Preferably, the communication system (10) is a remote convenience system for remotely controlling a convenience function.

Claims

1. A transmitter comprising:

means for providing a message package;

means for encrypting a first fraction of the message package using a second fraction of the message package as an encryption key; and

means for outputting a signal that conveys the encrypted first fraction of the message package,

wherein said means for providing a message package includes means for providing the message package to contain first and second portions, and to have a predefined number of bits, the first fraction of the message package includes the first portion and a first part of the second portion, the first portion and the first part of the second portion containing fewer bits than the predefined number, the second fraction including a second part of the second portion, said means for encrypting includes means for encrypting the first portion and the first part of the second portion using the second part of the second portion as the encryption key, and said means for outputting includes means for outputting the signal to convey the encrypted first portion and the encrypted first part of the second portion,

wherein said means for providing a message package includes means for providing the first portion of the message package to include a command and for providing the second portion of the message package to include a sequence counter, and

wherein the first part of the second portion of the message package includes least significant bits of the sequence counter and the second part of the second portion of the message package includes most significant bits of the sequence counter, said means for encrypting the first portion and the first part of the second portion includes means for using the most significant bits of the sequence counter as the encryption key.

2. A receiver comprising:

means for receiving an encrypted signal;

means for decrypting the signal using a decryption key; and

means for assembling a message package using the decryption key as part of the message package,

wherein said means for receiving includes means for receiving the signal to convey an encrypted first portion of the message package and an encrypted first part of a second portion the message package, the first portion and the first part of the second portion contain a predefined number of bits, said means for assembling includes means for assembling the second portion of the message package using the decryption key as a second part of the second portion of the message package, the assembled message package contains more bits than the predefined number,

wherein the first portion of the message package includes a command and the second portion of the message package includes a sequence counter, said means for decrypting includes means for decrypting using a value representing part of the sequence counter as the decryption key, and

wherein the first part of the second portion of the message package includes least significant bits of the sequence counter and the second part of the second portion includes most significant bits of the sequence counter, said means for decrypting using a value representing part of the sequence counter includes means for using a value representing the most significant bits of the sequence counter as the decryption key.

3. A receiver as set forth in claim 2, including a memory for storing the sequence counter, an updated sequence counter is stored in the memory after each received message package, said means for decrypting includes means for accessing the memory to retrieve the value representing the part of the sequence counter.

4. A communication system comprising:

means for providing a message package;

means for encrypting a first fraction of the message package using a second fraction of the message package as an encryption key;

means for outputting a signal that conveys the encrypted first fraction of the message package;

means for receiving the signal;

means for decrypting the signal using a decryption key; and

means for reassembling the message package using the decryption key as the second fraction of the message package,

wherein said means for providing a message package includes means for providing the message package to contain first and second portions, and to have a predefined number of bits, the first fraction of the message package includes the first portion and a first part of the second portion, the first portion and the first part of the second portion containing fewer bits than the predefined number, the second fraction including a second part of the second portion, said means for encrypting includes means for encrypting the first portion and the first part of the second portion using the second part of the second portion as the encryption key, said means for outputting includes means for outputting the signal to convey the encrypted first portion and the encrypted first part of the second portion, and said means for reassembling includes means for assembling the second portion of the message package using the decryption key as the second part of the second portion of the message package,

wherein said means for providing the message package to contain first and second portions includes means for providing the first portion of the message package to includes a command and for providing the second portion of the message package to include a sequence counter, and

wherein the first part of the second portion includes least significant bits of the sequence counter and the second part of the second portion includes most significant bits of the sequence counter, said means for encrypting the first portion and the first part of the second portion includes means for using the most significant bits of the sequence counter as the encryption key.

5. A communication system comprising:

means for providing a message package;

means for encrypting a first fraction of the message package using a second fraction of the message package as an encryption key;

means for outputting a signal that conveys the encrypted first fraction of the message package;

means for receiving the signal;

means for decrypting the signal using a decryption key; and

means for reassembling the message package using the decryption key as the second fraction of the message package,

wherein said means for providing a message package includes means for providing the message package to contain first and second portions, and to have a predefined number of bits, the first fraction of the message package includes the first portion and a first part of the second portion, the first portion and the first part of the second portion containing fewer bits than the predefined number, the second fraction including a second part of the second portion, said means for encrypting includes means for encrypting the first portion and the first part of the second portion using the second part of the second portion as the encryption key, said means for outputting includes means for outputting the signal to convey the encrypted first portion and the encrypted first part of the second portion, and said means for reassembling includes means for assembling the second portion of the message package using the decryption key as the second part of the second portion of the message package,

wherein said means for providing the message package to contain first and second portions includes means for providing the first portion of the message package to includes a command and for providing the second portion of the message package to include a sequence counter, and

wherein the first part of the second portion includes least significant bits of the sequence counter and the second part of the second portion includes most significant bits of the sequence counter, said means for decrypting using a value representing part of the sequence counter includes means for using a value representing the most significant bits of the sequence counter as the decryption key.

6. A system as set forth in claim 5, including a memory for storing the sequence counter, an updated sequence counter is stored in the memory after each received message package, said means for decrypting includes means for accessing the memory to retrieve the value representing the part of the sequence counter.

7. A system as set forth in claim 5, wherein said means for assembling the second portion of the message package includes means for assembling the sequence counter with the most significant bits and the least significant bits.

8. A remote convenience system for remotely controlling a convenience function, said system comprising:

portable transmitter means for outputting a signal containing remote control message information; and

receiver/controller means for receiving the signal and controlling performance of a function in accordance with a command provided in the remote control message information;

wherein the remote control message information includes first and second fractions, said transmitter means includes encryption means for encrypting the first fraction of the remote control message information using a second fraction of the remote control message information as an encryption key,

wherein the remote control message information includes first and second information portions, the first fraction of the remote control message information includes first information portion and a first part of the second information portion of the remote control message information, the second fraction of the remote control message information includes a second part of the second information portion of the remote control message information, said encryption means including means for encrypting the first information portion and the first part of the second information portion using the second part of the second information portion as the encryption key,

wherein the first information portion of the remote control message information includes command and the second information portion of the message package includes a sequence counter, and

wherein the first part of the second information portion includes least significant bits of the sequence counter and the second part of the second information portion includes most significant bits of the sequence counter, said means for encrypting the first information portion and the first part of the second information portion includes means for using the most significant bits of the sequence counter as the encryption key.

9. A transmitter comprising:

means for providing a message package that includes first and second message portions, the second message portion including least significant bits and most significant bits;

means for forming an encrypted message by using a first one of the least significant bits and the most significant bits of the second message portion as an encryption key for encrypting the first message portion and a second one of the least significant bits and the most significant bits of the second message portion; and

means for transmitting a signal that includes encrypted message.

10. The transmitter of claim 9 wherein the most significant bits of the second message portion are used as the encryption key for encrypting the first message portion and the least significant bits of the second message portion.

11. The transmitter of claim 9 wherein the message package includes a first number of bits and the encrypted message includes a second number of bits that is less than the first number of bits by an amount equal to a number of bits used as the encryption key.

12. The transmitter of claim 9 wherein the first message portion includes an identification code associated with the transmitter.

13. The transmitter of claim 9 wherein the first message portion includes an identification code and a command and wherein the second message portion is a sequence counter, the most significant bits of the sequence counter being used as the encryption key for encrypting the identification code, the command, and the least significant bits of the sequence counter so that the encrypted message is smaller in size than the message package by a number of bits used as the encryption key.

14. The transmitter of claim 9 wherein the means for transmitting the signal that includes encrypted message further includes means for transmitting a radio frequency signal.

15. A receiver comprising:

means for receiving a signal that includes an encrypted message, the encrypted message including a first message portion and a first part of a second message portion, the first part of the second message portion including a first one of least significant bits of the second message portion and most significant bits of the second message portion;

means for decrypting the encrypted message using a decryption key, the decryption key being a second one of the least significant bits of the second message portion and the most significant bits of the second message portion; and

means for assembling a message package that includes first message portion and both the least significant bits and the most significant bits of the second message portion.

16. The receiver of claim 15 wherein the most significant bits of the second message portion are used as the decryption key for decrypting the encrypted message.

17. The receiver of claim 15 wherein the encrypted message includes a first number of bits and the message package that is assembled includes a second number of bits that is greater than the first number of bits by a number of bits used as the decryption key.

18. The receiver of claim 15 wherein the first message portion includes an identification code associated with a transmitter from which the signal originated.

19. The receiver of claim 15 wherein the first message portion includes an identification code and a command and wherein the second message portion is a sequence counter, the most significant bits of the sequence counter being used as the decryption key for decrypting the identification code, the command, and the least significant bits of the sequence counter of the encrypted message so that the message package that is assembled is larger in size than the encrypted message by a number of bits used as the decryption key.

20. The receiver of claim 19 wherein the means for receiving the signal further includes means for transmitting a radio frequency signal.

21. A communication system comprising:

means for providing a message package that includes a first message portion and a second message portion, the second message portion including least significant bits and most significant bits;

means for forming an encrypted message by using a first one of the least significant bits and the most significant bits of the second message portion as an encryption key to encrypt the first message portion and a second one of the least significant bits and the most significant bits of the second message portion;

means for transmitting a signal that includes encrypted message;

means for receiving the signal that includes encrypted message;

means for decrypting the encrypted message using a decryption key, the decryption key also being the first one of the least significant bits and the most significant bits of the second message portion; and

means for assembling the message package that includes first message portion and both the least significant bits and the most significant bits of the second message portion.

22. The system of claim 21 wherein the first one of the least significant bits and the most significant bits of the second message portion is the least significant bits of the second message portion and the second one of the least significant bits and the most significant bits of the second message portion is the most significant bits and wherein the first message portion includes an identification code.

23. The system of claim 21 wherein the first message portion includes an identification code and a command, the second message portion including a sequence counter, the most significant bits of the sequence counter being used as the encryption key for encrypting the identification code, the command, and the least significant bits of the sequence counter.

24. The system of claim 21 wherein the means for transmitting the signal that includes encrypted message further includes means for transmitting a radio frequency signal and wherein the means for receiving the signal further includes means for receiving the radio frequency signal.

25. A remote convenience system for remotely controlling a convenience function, the system comprising:

portable transmitter means for transmitting a signal that includes an encrypted message, the encrypted message including a first message portion and a first part of a second message portion of a message package, a second part of the second message portion of the message package forming an encryption key for encrypting the first message portion and the first part of the second message portion of the message package, the first part of the second message portion including a first one of least significant bits of the second message portion and most significant bits of the second message portion and the second part of the second message portion including a second one of the least significant bits and the most significant bits of the second message portion;

receiver/controller means for receiving the signal that includes the encrypted message and for decrypting the encrypted message using a decryption key, the decryption key also being the second one of the least significant bits and the most significant bits of the second message portion, the receiver/controller means assembling the message package having the first message portion and both the least significant bits and the most significant bits of the second message portion.

26. The system of claim 25 wherein the system is associated with a vehicle and the receiver/controller means including means for controlling performance of a vehicle function in accordance with the message package that is assembled.

27. The system of claim 25 wherein the second one of the least significant bits and the most significant bits of the second message portion is the most significant bits of the second message portion.

28. The system of claim 25 wherein the first message portion includes an identification code and a command, the second message portion including a sequence counter, the most significant bits of the sequence counter being used as the encryption key for encrypting the identification code, the command, and the least significant bits of the sequence counter.