Wireless power charging with authentication

Patent metadata

Field	Value
Publication number	US-12034320-B2
Application number	US-202117321312-A
Country	US
Kind code	B2
Filing date	May 14, 2021
Priority date	Jun 8, 2020
Publication date	Jul 9, 2024
Grant date	Jul 9, 2024

Abstract

An authentication method for authenticating a wireless power transmitter to a wireless power receiver includes receiving a SSP value, an ID, and a random number RND from a wireless power receiver; determining an index based on the RND; choosing a base code from a set of base codes according to the index; determining a secure code from the base code, the index, the RND, the SSP value, and the ID; and transmitting the secure code to the wireless power receiver. A further method includes receiving a secure code from the wireless power transmitter; retrieving an index from the secure code; determining a base code from a set of base codes according to the index; calculating a second secure code; and authenticating the wireless power transmitter by comparing the secure code and the second secure code.

First claim

What is claimed is:

1. A method of authentication, comprising:
receiving a signal strength packet (SSP) value, an ID, and a random number RND from a wireless power receiver;
determining an index based on the RND;
choosing a base code from a set of base codes according to the index;
determining a secure code from the base code, the index, the RND, the SSP value, and the ID; and
transmitting the secure code to the wireless power receiver,
wherein determining the index includes
determining at least one transmit random number TX RND; RND, and
convoluting the RND with the at least one TX RND to yield the index, wherein the index is in a range that spans the set of base codes.

2. The method of claim 1 , wherein the at least one TX RND includes a TX RND 1 and a TX RND 2 and the index is given by
Index=(RND) XOR ( TX RND 1) XOR ( TX RND 2) MOD 16.

3. The method of claim 1 , wherein the set of base codes includes sixteen 5-byte codes.

4. A method of authentication, comprising:
receiving a signal strength packet (SSP) value, an ID, and a random number RND from a wireless power receiver;
determining an index based on the RND;
choosing a base code from a set of base codes according to the index;
determining a secure code from the base code, the index, the RND, the SSP value, and the ID; and
transmitting the secure code to the wireless power receiver,
wherein determining the secure code includes
convoluting the base code with the ID, SSP, and the RND to form a pre-secure code, and
assembling the secure code from the pre-secure code and the index.

5. The method of claim 4 , wherein the convoluting to form the pre-secure code includes:
selecting a plurality of bytes from the ID;
assembling a code of length equal to that of the base code from the plurality of bytes from the ID, the SSP, and the RND; and
convoluting the base code with the code.

6. The method of claim 5 , wherein the ID includes bytes ID B4, ID B5, and ID B6, and wherein the code is given by (ID B4, SSP, RND, ID B6, ID B5) and convoluting the base code with the code yields the pre-secure code as
(base code) XOR (ID B 4, SSP, RND, ID B 6, ID B 5).

7. The method of claim 4 , wherein assembling the secure code from the pre-secure code includes
selecting a plurality of half-bytes from the pre-secure code; and
arranging the plurality of half-bytes and the index into the secure code.

8. The method of claim 7 , wherein selecting a plurality of half-bytes form the pre-secure code includes selecting at least one half-byte from each byte of the pre-secure code.

9. A method of authentication, comprising:
receiving a signal strength packet (SSP) value, an ID, and a random number RND from a wireless power receiver;
determining an index based on the RND;
choosing a base code from a set of base codes according to the index;
determining a secure code from the base code, the index, the RND, the SSP value, and the ID; and
transmitting the secure code to the wireless power receiver,
wherein determining the secure code includes
determining a hash input from the ID, the SSP value, the random number, and the base code;
performing a hashing function on the hash input to determine a hash code; and
assembling the secure code from the hash code and the index.

10. The method of claim 9 , wherein assembling the secure code includes
selecting a plurality of half-bytes from the hash code; and
arranging the plurality of half-bytes with the index into the secure code.

11. A method of authentication, comprising:
transmitting a single strength packet (SSP) value, an ID, and a random number to a wireless power transmitter;
receiving a secure code from the wireless power transmitter;
retrieving an index from the secure code;
determining a base code from a set of base codes according to the index;
calculating a second secure code from the SSP, the ID, the random number, and the base code; and
authenticating the wireless power transmitter by comparing the secure code and the second secure code,
wherein calculating the second secure code includes
convoluting the base code with the ID, SSP, and random number to form a pre-secure code; and
assembling the second secure code from the pre-secure code and the index.

12. The method of claim 11 , wherein the convoluting to form the pre-secure code includes:
selecting a plurality of bytes from the ID;
assembling a code of length equal to that of the base code from the plurality of bytes from the ID, the SSP, and the RND; and
convoluting the base code with the code.

13. A method of authentication, comprising:
transmitting a single strength packet (SSP) value, an ID, and a random number to a wireless power transmitter;
receiving a secure code from the wireless power transmitter;
retrieving an index from the secure code;
determining a base code from a set of base codes according to the index;
calculating a second secure code from the SSP, the ID, the random number, and the base code; and
authenticating the wireless power transmitter by comparing the secure code and the second secure code,
wherein calculating the second secure code includes
determining a hash input from the ID, the SSP value, the random number, and the base code;
performing a hashing function on the hash input to determine a hash code; and
assembling the secure code from the hash code and the index.

14. A wireless power transmitter, comprising:
an inverter coupled to drive a transmission coil;
a FSK modulator coupled to the inverter to transmit data to a wireless power receiver;
an ASK demodulator coupled to the inverter to receive data from the wireless power receiver; and
a processor coupled to the inverter, the FSK modulator, and the ASK demodulator, the processor executing instructions to
receive a SSP value, an ID, and a random number RND from a wireless power receiver;
determine an index based on the RND;
choose a base code from a set of base codes according to the index;
determine a secure code from the base code, the index, the RND, the signal strength packet (SSP) value, and the ID; and

transmit the secure code to the wireless power receiver,
wherein the instructions to determine the index includes instructions to
determine at least one transmit random number TX RND;
convolute the RND with the at least one TX RND to yield the index, wherein the index is in a range that that spans the set of base codes.

15. A wireless power transmitter, comprising:
an inverter coupled to drive a transmission coil;
a FSK modulator coupled to the inverter to transmit data to a wireless power receiver;
an ASK demodulator coupled to the inverter to receive data from the wireless power receiver; and
a processor coupled to the inverter, the FSK modulator, and the ASK demodulator, the processor executing instructions to
receive a SSP value, an ID, and a random number RND from a wireless power receiver;
determine an index based on the RND;
choose a base code from a set of base codes according to the index;
determine a secure code from the base code, the index, the RND, the signal strength packet (SSP) value, and the ID; and

transmit the secure code to the wireless power receiver,
wherein instructions to determine the secure code includes instructions to
convolute the base code with the ID, SSP, and the RND to form a pre-secure code; and
assemble the secure code from the pre-secure code and the index.

16. The wireless power transmitter of claim 15 , wherein instructions to assemble the secure code from the pre-secure code includes instructions to

Assignees

• Renesas Electronics America Inc

Inventors

• Kim Changjae
• Acar Damla
• Dzebic Adnan
• Agrawal Pooja
• Yi Sophia

Classifications

• H02J7/47 Primary

  Arrangements for checking compatibility or authentication between one component, e.g. a battery or a battery charger, and another component, e.g. a power source · CPC title

• H02J7/40

  characterised by the exchange of charge or discharge related data · CPC title

• H04L9/3239

  involving non-keyed hash functions, e.g. modification detection codes [MDCs], MD5, SHA or RIPEMD · CPC title

• H04L9/0869

  involving random numbers or seeds · CPC title

• H04L9/3236 Primary

  using cryptographic hash functions · CPC title