Battery authentication system

• US 20050188206A1
• Filed: 06/24/2004
• Published: 08/25/2005
• Est. Priority Date: 02/24/2004
• Status: Active Grant

• Current Assignee: Intersil Americas LLC (Renesas Electronics Corporation)
• Original Assignee: Intersil Americas LLC (Renesas Electronics Corporation)
• Inventors: Kwok, Chung Y.
• Granted Patent: US 7,596,699 B2
• Time in Patent Office: Days
• US Class Current: 713/176
• CPC Class Codes: H04L 9/3271 using challenge-response

Abstract

An authentication process for authenticating a battery to a cellular telephone includes the step of receiving a challenge from the cellular telephone at the battery over a single wire conductor. In response to the challenge, the seed values are retrieved from the memory and a response is generated based upon the challenge and the seed values. The response is transmitted back to the cellular telephone from the battery over the single conductor so that a comparison with a similar response generated by the cellular telephone may be made.

Claims

1. An authentication process for authenticating a battery to a cellular telephone, comprising:

receiving a challenge from the cellular telephone at the battery over a single conductor;

retrieving seed values by the battery from a memory;

generating a response based on the challenge and the seed values; and

transmitting the response from the battery to the cellular telephone over the single conductor.

2. The authentication process of claim 1 further comprising:

retrieving second seed values by the cellular telephone from a second memory;

generating a second response based on the challenge and the second seed values;

comparing the response to the second response; and

authenticating the battery based upon the comparison.

3. The authentication process of claim 1, wherein said step of generating a response comprises performing a hash function on the challenge to generate a hash code.

4. The authentication process of claim 3, wherein said hash function is a cyclic redundancy code function.

5. The authentication process of claim 1, wherein said step of generating a response comprises performing a plurality of hash calculations.

6. The authentication process of claim 5 further comprising the step of selectively inputting bits to the hash calculations.

7. The authentication process of claim 6, wherein said step of selectively inputting bits comprises selectively inputting challenge bits and serial output bits to the hash calculations.

8. The authentication process of claim 5, wherein said plurality of hash calculations are a plurality of cyclic redundancy code calculations.

9. The authentication process of claim 5, wherein said plurality of hash calculations generate a plurality of output hash codes.

10. The authentication process of claim 7, wherein the step of generating a response comprises combining the generated plurality of output hash codes.

11. The authentication process of claim 1, wherein said step of generating a response comprises generating a plurality of output cyclic redundancy codes.

12. The authentication process of claim 11, wherein said step of generating a response comprises the step of combining the generated plurality of output cyclic redundancy codes.

13. The authentication process of claim 1, wherein said seed values include a polynomial code.

14. The authentication process of claim 1, wherein said seed values include initial register values.

15. The authentication process of claim 1, wherein said seed values include multiplexer address values.

16. The authentication process of claim 1, where in the step of transmitting further comprises the steps of:

maintaining the conductor at a first voltage level when data is not being transmitted from the battery to the cellular telephone;

during a data transfer operation of a bit of information;

driving the voltage on the conductor from the first voltage level to a second voltage level,

maintaining the voltage on the conductor at substantially the second voltage level for a predetermined duration of time, which predetermined duration of time has a length that is determined by the logic state of the data bit, and

at the end of the predetermined duration of time, driving the voltage level on the conductor to substantially the first voltage level.

17. The authentication process of claim 16, wherein the data bit has two logic states, a first logic state and a second logic state.

18. The authentication process of claim 17, wherein the predetermined duration of time has a first duration associated with the first logic state and a second duration associated with the second logic state.

19. The authentication process of claim 18, wherein the first duration of time has a minimum value and a maximum value and wherein the first logic state is valid only after the minimum value of the first duration of time.

20. The authentication process of claim 19, wherein the second duration has a minimum value that is equal to or greater than the maximum value of the first duration of time, and a maximum value, and wherein the second logic state is valid only after the minimum value of the second duration of time.

21. The authentication process of claim 16, wherein the step of maintaining the conductor at a first voltage level when data is not being transmitted from the transmitter to the receiver comprises the step of weakly pulling the conductor to the first voltage level.

22. The authentication process of claim 21, wherein the step of weakly pulling the conductor to the first voltage level comprises disposing a passive load between a voltage source disposed at the first voltage level and the conductor.

23. The authentication process of claim 22, wherein the step maintaining the voltage on the conductor at substantially the second voltage level for a predetermined duration of time comprises driving the conductor with an active device disposed between the conductor and a voltage source disposed at the second voltage level.

24. The authentication process of claim 1, wherein the step of receiving further comprises the steps of:

detecting a first transition of a voltage level on the single conductor from a first voltage level to a second voltage level indicating the initiation of the operation of a data transfer operation of a bit of the challenge from the cellular telephone;

detecting a second transition of the voltage level on the single conductor from the second voltage level to the first voltage level indicating the end of the operation of the data transfer operation of a bit of information from the cellular telephone;

determining the duration of time between the first and second data transitions;

wherein the data bit transferred has a plurality of logic states, each associated with a different value of the duration of time between the first and second transitions; and

determining from the length of the determined duration of time the logic state of transmitted data bit.

25. The authentication process of claim 24, wherein the data bit has two logic states, a first logic state and a second logic state.

26. The authentication process of claim 25, wherein the duration of time between the first and second transitions has a first duration of time associated with the first logic state and a second duration of time associated with the second logic state.

27. The authentication process of claim 26, wherein the first duration of time has a minimum value and a maximum value and wherein the step of determining the logic state of the transmitted data bit determines that the logic state of the transmitted data corresponds to the first logic state if the second transition occurs at or after the minimum value and at or before the maximum of the first duration of time.

28. The authentication process of claim 22, wherein the second duration has a minimum value that is equal to or greater than the maximum value of the first duration of time, and a maximum value, and wherein the step of determining the logic state of the transmitted data determines that the logic state of the transmitted data corresponds to the second logic state if the second transition occurs at or after the minimum value and at or before the maximum value of the second duration of time.

29. The authentication process of claim 25, wherein the duration of time between the first and second transitions comprises a pulse width, and the first logic state corresponds to a pulse width of a first width and the second logic state corresponds to a pulse width of a second width greater than the first pulse width.

30. The authentication process of claim 29, wherein the first width has a minimum value and a maximum value and wherein the step of determining determines that the logic state of the transmitted data corresponds to the first logic state if the second transition occurs at or after the minimum value and at or before the maximum value of the first pulse width.

31. The authentication process of claim 30, wherein the second pulse width has a minimum value that is equal to or greater than the maximum value of the first pulse width and a maximum value, and wherein the step of determining determines that the logic state corresponds to the second logic state if the second transition occurs at or after the minimum value and at or before the maximum value of the second pulse width.

32. A method for authenticating a battery in a cellular telephone, comprising the steps of:

detecting insertion of the battery into the cellular telephone;

transmitting a challenge to the battery from the cellular telephone over a single wire conductor;

calculating authorization codes from the battery and the cellular telephone responsive to the challenge;

transmitting the battery authorization code to the cellular telephone over the single wire conductor;

comparing the battery authorization code with the cellular telephone authorization code; and

determining authorization of the battery based upon the comparison.

33. The method of claim 32, wherein said step of calculating authorization codes comprises performing a hash function on the challenge to generate a hash code.

34. The method of claim 33, where in the steps of transmitting further comprises the steps of:

maintaining the conductor at a first voltage level when data is not being transmitted from the battery to the cellular telephone;

during a data transfer operation of a bit of information;

driving the voltage on the conductor from the first voltage level to a second voltage level,

maintaining the voltage on the conductor at substantially the second voltage level for a predetermined duration of time, which predetermined duration of time has a length that is determined by the logic state of the data bit, and

at the end of the predetermined duration of time, driving the voltage level on the conductor to substantially the first voltage level.

35. The method of claim 33, wherein said hash function is a cyclic redundancy code function.

36. The method of claim 32, wherein said step of calculating authorization codes comprises performing a plurality of hash calculations.

37. The method of claim 36 further comprising the step of selectively inputting bits to the hash calculations.

38. The method of claim 37, wherein said step of selectively inputting bits comprises selectively inputting challenge bits and serial output bits to the hash calculations.

39. The method of claim 32, wherein the step of generating further comprises the step of retrieving seed value from a memory.

40. The authentication process of claim 39, wherein said seed values include a polynomial code.

41. The authentication process of claim 40, wherein said seed values include initial register values.

42. The authentication process of claim 39, wherein said seed values include multiplexer address values.