System and method for encrypted communications between electronic devices

• US 6,957,333 B2
• Filed: 09/12/2002
• Issued: 10/18/2005
• Est. Priority Date: 09/12/2002
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: He, Duanfeng
• Primary Examiner(s): Sheikh, Ayaz
• Assistant Examiner(s): Sherkat, Arezoo
• Application Number:
  US10/242,401
• Publication Number:
  US 20040054900A1
• Time in Patent Office: 1,132 Days
• Field of Search: 713/168, 713/183, 705/65, 340/5.61, 340/572.1, 340/573.1, 119/863
• US Class Current: 713/168
• CPC Class Codes: H04L 2209/08 Randomization, e.g. dummy operations or using noise
• CPC Class Codes: H04L 2209/805 Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
• CPC Class Codes: H04L 9/0822 using key encryption key
• CPC Class Codes: H04L 9/14 using a plurality of keys or algorithms

Abstract

Described is a system and method for encrypted communications. The system may include first and second transponders. The first transponder has a first memory arrangement that stores a first key. The second transponder includes a second memory arrangement and has an access to a second key. The first transponder generates a first message for delivery to the second transponder, and encrypts the first message using a randomization key to generate a second message. Then, the first transponder encrypts (a) the second message and (b) one of the a randomization key corresponding index using the first key to generate a third message. The second key may decrypt the third message.

Claims

1. A system for encrypted communications, comprising:

a first transponder including a first memory arrangement which stores a first key;

a second transponder including a second memory arrangement and having an access to a second key,

wherein the first transponder generates a first message to the second transponder, the first transponder encrypting the message using a randomization key to generate a second message, the first transponder encrypting (a) the second message and (b) one of the randomization key and an index to the randomization key using the first key to generate a third message,

wherein the second key is capable of decrypting the third message, wherein the third message includes the index to the randomization key, wherein a plurality of randomization keys and corresponding indexes are stored in each of the first and second memory arrangements.

2. The system according to claim 1, wherein the first and second transponders are RFID transponders.

3. The system according to claim 1, wherein one of the first and second transponders is embedded into merchandise and another transponder is a portable transponder.

4. The system according to claim 3, wherein the first memory arrangement includes data relating to the merchandise.

6. The system according to claim 1, wherein the first key is public key and the second key is a corresponding private key.

7. The system according to claim 1, wherein the first and second keys are replaceable with a corresponding pair of further first and further second keys.

8. The system according to claim 1, wherein the first transponder generates the first message in response to a request submitted by the second transponder.

9. The system according to claim 8, wherein the first message is not generated if the first key is absent from the first memory arrangement.

10. The system according to claim 1, wherein the third message includes the randomization key, the second transponder receives and decrypts the third message using the second key to generate the second message and the randomization key, the second transponder decrypting the second message using the randomization key to generate the first message.

11. The system according to claim 1, wherein the second transponder receiving and decrypting the third message using the second key to generate the second message and the index, the second transponder decrypting the second message using the randomization key which corresponds to the index to generate the first message.

12. The system according to claim 1, wherein each of the first and second memory arrangements includes a first portion which is a read-only memory and a second portion which is a rewritable memory, the first portion storing a plurality of randomization keys.

13. The system according to claim 12, wherein the second portion temporarily stores the randomization key.

14. The system according to claim 12, wherein the second portion stores the first key.

15. The system according to claim 12, wherein the second portion stores the second key.

16. The system according to claim 1, wherein the first memory arrangement stores a plurality of randomization keys and wherein the randomization key is randomly selected from the plurality of the randomization keys.

17. The system according to claim 1, wherein the randomized key is generated by the first transponder based on a preexisting randomization algorithm.

18. The system according to claim 1, wherein the second key is stored in the second memory arrangement.

19. The system according to claim 1, wherein the second key is stored in a remote computer which is connected to a digital communication network, the second transponder having the access to the second key via the digital communication network.

20. The system according to claim 1, wherein one of the first and second transponders is embedded into merchandise and another transponder includes a portable transponder and a computer, the portable transponder coupled to the computer, the computer including the second memory arrangement, the portable transponder transmitting the third message between the computer and the transponder embedded into the merchandise.

5. The system according to clam 4, wherein the data includes at least one of a serial number of the merchandise, a part number and a description of the merchandise.

21. A method for encrypted communications, comprising the steps of:

generating a first message by a first transponder for delivery to the second transponder, the first transponder including a first memory arrangement which stores a first key, the second transponder including a second memory arrangement and having an access to a second key;

encrypting the first message using a randomization key to generate a second message by the first transponder; and

encrypting (a) the second message and (b) one of the randomization key and a corresponding index using the first key to generate a third message by the first transponder,

wherein the second key is capable of decrypting the third message, wherein the third message includes the index to the randomization key, wherein a plurality of randomization keys and corresponding indexes are stored in each of the first and second memory arrangements.

22. The method according to claim 21, wherein the first and second transponders are RFID transponders.

23. The method according to claim 21, further comprising the step of:

embedding one of the transponders into merchandise,

wherein the other one of the transponders is a portable transponder.

24. The method according to claim 23, wherein the first memory arrangement includes data relating to the merchandise.

26. The method according to claim 21, wherein the first key is public key and the second key is a corresponding private key.

27. The method according to claim 21, further comprising the steps of:

removing the first and second keys; and

installing a corresponding pair of further first and further second keys in place of the first and second keys.

28. The method according to claim 21, further comprising the step of:

before the generating step, submitting a request by the second transponder to the first transponder,

wherein the first transponder generates the first message in response to the request.

29. The method according to claim 28, further comprising the step of:

refusing to generate the first message by the first transponder when the first key is absent from the first memory arrangement.

30. The method according to claim 21, wherein the third message includes the randomization key, the method further comprising the steps of:

receiving by the second transponder the third message;

decrypting the third message using the second key to generate the second message and the randomization key; and

decrypting the second message using the randomization key to generate the first message.

31. The method according to claim 21, wherein the third message includes the index to randomization key, wherein a plurality of randomization keys and corresponding indexes are stored in each of the first and second memory arrangements, the method further comprising the steps of:

receiving by the second transponder the third message;

decrypting the third message using the second key to generate the second message and the index; and

decrypting the second message using the randomization key code which corresponds to the index to generate the first message.

32. The method according to claim 21, wherein each of the memory arrangements include a first portion which a read-only memory and a second portion which is a rewritable memory, the first portion storing the plurality of randomization keys.

33. The method according to claim 32, further comprising the step of:

temporarily storing the randomization key in the second portion.

34. The method according to claim 32, further comprising the step of:

storing the first key in the second portion.

35. The method according to claim 30, further comparing the step of:

storing the second key in the second portion.

36. The method according to claim 21, wherein the first memory arrangement storing a plurality of randomization keys, the method further comprising the step of:

randomly selecting the randomization key from the plurality from the plurality of randomization keys.

37. The method according to claim 21, further comprising the step of:

generating the randomization key by the first transponder based on a preexisting randomization algorithm.

38. The method according to claim 21, wherein the second key is stored in the second memory arrangement.

39. The method according to claim 21, wherein the second key is stored in a remote computer which is connected to a digital communication network, the method further comprising the step of:

accessing the second key by the second transponder via the digital communication network.

40. The method according to claim 21, wherein one of the first and second transponders is embedded into merchandise and another transponder includes a portable transponder and a computer, the portable transponder coupled to the computer, the computer including the second memory arrangement, the method further comprising the step of:

with the portable transponder, transmitting the third message between the computer and the transponder embedded into the merchandise.

25. The method according to clam 24, wherein the data includes at least one of a serial number of the merchandise, a part number and a description of the merchandise.