Rechargeable battery pack and operating system

• US 7,941,865 B2
• Filed: 11/20/2006
• Issued: 05/10/2011
• Est. Priority Date: 11/01/2005
• Status: Active Grant

• Current Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Inventors: Brotto, Daniele C., Seman, Andrew E. Jr., Qin, Fugen, Trinh, Danh T.
• Primary Examiner(s): Pich; Ponnoreay
• Assistant Examiner(s): BEHESHTI SHIRAZI, SAYED ARESH
• Application Number:
  US11/554,937
• Publication Number:
  US 20080037779A1
• Time in Patent Office: 1,632 Days
• Field of Search: 380/47, 380 44- 46, 380277-278, 713168-170, 726/34, 726/36, 705/50, 705 60- 61
• US Class Current: 726/34
• CPC Class Codes: H02J 7/00036 Charger exchanging data with battery
• CPC Class Codes: H02J 7/00047 with provisions for charging different types of batteries
• CPC Class Codes: H04L 9/065 Encryption by serially and continuously modifying data stream elements, e.g. stream cipher systems, RC4, SEAL or A5/3
• CPC Class Codes: H04L 9/3271 using challenge-response
• CPC Class Codes: Y04S 40/20 Information technology specific aspects, e.g. CAD, simulation, modelling, system security

Abstract

A method and system for authenticating a smart battery having a smart battery and an electronic device. Both the device and the smart battery generate encrypted random strings using key material based by A/D noise bits as a seed value. A pseudo random number is generated from the A/D noise that is transmitted to both the electronic device and the smart battery. The pseudo random number is used by both devices as a key index to select one of a plurality of keys stored in separate key libraries. The keys, or key material, is used to execute an encryption algorithm. The two encryption data streams are then compared to authenticate the smart battery.

Claims

1. A method for charging a smart battery, the method comprising:

generating an encrypted random string using key material determined by a timed asynchronous random event as a seed value, wherein the encrypted random string includes a random string in an encrypted form, wherein the generating step includes selecting key material from one or more arbitrary keys stored in a key library based on A/D noise bits as a seed value; and

transferring the random string to a device and decrypting the encrypted random string to recover the random string for authenticating the smart battery for operation, the device being electrically coupled to the smart battery.

2. The method of claim 1, wherein the generating step includes calculating a pseudo random number based on A/D noise bits as a seed value.

3. The method of claim 2, wherein the selecting key material step includes determining a key index from the pseudo random number.

4. The method of claim 2, wherein the pseudo random number is at least 8 bits.

5. The method of claim 2, wherein the pseudo random number is at least 64 bits.

6. The method of claim 2, wherein the pseudo random number is at least 128 bits.

7. The method of claim 3, wherein calculating a pseudo random number is fixed after reading A/D noise bits at a predetermined time.

8. The method of claim 3, wherein calculating a pseudo random number is variable after reading A/D noise bits at different time intervals.

9. The method of claim 1, wherein generating and transferring steps occur upon connection of the battery with the electronic device.

10. The method of claim 1, further comprising:

generating a second encrypted random string by said device using key material determined by A/D noise bits as a seed value wherein the second encrypted random string includes a random string in an encrypted form; and

comparing the first and the second encrypted random string to a device for authenticating the smart battery.

11. The method of claim 10, wherein the electronic device is a charger.

12. The method of claim 10, wherein the electronic device is a power tool.

13. A smart battery authentication system comprising:

a smart battery, wherein the smart battery includes;

a smart electronics device operable to generate a first encrypted random string using key material from one or more arbitrary key stored in a key library selected based on A/D noise bits as a seed value, wherein the encrypted random string includes a random string in an encrypted form; and

an electronic device having a controller operable to generate a second encrypted random string based on A/D noise bits as a seed value and to receive the first encrypted random string to authenticate the smart battery;

a communications bus for electrically coupling the smart electronics to the controller; and

the controller operable to authenticate the smart battery by comparing the first and second encrypted random strings.

14. The system of claim 13, wherein the smart battery calculates a pseudo random number based on A/D noise bits as a seed value.

15. The system of claim 14, wherein the smart battery selects key material by determining a key index from the pseudo random number.

16. The system of claim 15, wherein the smart battery calculates a pseudo random number after reading A/D noise bits at a fixed predetermined time.

17. The system of claim 15, wherein the smart battery calculates a pseudo random number after reading A/D noise bits at variable time intervals.

18. The system of claim 13, wherein the smart battery generates the first encrypted random string upon connection of the smart battery with the electronic device.