# US 12,113,790 B2 · Mutual authentication and re-authentication method between wireless power transmitting device and wireless power receiving device, and wireless power transmitting device and wireless power receiving device using same

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- Number: US 12,113,790 B2
- Document ID: US12113790B2
- Status: Granted
- Kind: B2
- Application number: 17/626,282
- Filed: 2020-07-13
- Published: 2022-08-18
- Granted: 2024-10-08
- Earliest claimed: 2019-07-12
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Jaehyu Kim; Jingu Choi; Minsoo Lee; Jinkwon Lim
- Web page: https://patentgrep.com/patent/US12113790B2

## CPC

- H04L 63/0869: {for achieving mutual authentication (cryptographic mechanisms or cryptographic arrangements for mutual authentication H04L9/3273)}
- H02J 7/47: 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
- H02J 50/10: using inductive coupling
- H02J 50/40: using two or more transmitting or receiving devices (H02J50/50 takes precedence)
- H02J 50/80: involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
- H04B 5/79: for data transfer in combination with power transfer
- H04L 9/3239: {involving non-keyed hash functions, e.g. modification detection codes [MDCs], MD5, SHA or RIPEMD}
- H04L 9/3247: {involving digital signatures}
- H04L 9/3265: {using certificate chains, trees or paths; Hierarchical trust model}
- H04L 9/3273: {for mutual authentication (network architectures or network communication protocols for achieving mutual authentication in a packet data network H04L63/0869)}
- H04L 9/3297: {involving time stamps, e.g. generation of time stamps}
- H04L 63/0823: {using certificates (cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263)}
- H04L 63/102: {Entity profiles}
- H04L 63/123: {received data contents, e.g. message integrity}
- H04W 12/06: Authentication
- H04W 12/069: using certificates or pre-shared keys
- H02J 7/02: for charging batteries from AC mains by converters
- H04L 2209/80: Wireless
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H04B: TRANSMISSION
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

According to one embodiment of the present specification, a method for performing authentication between an authentication initiator and an authentication responder in a wireless power transmission system comprises the steps in which: the authentication initiator transmits an initiator certificate chain and an initiator signature to the authentication responder; the authentication initiator receives a responder certificate chain and a responder signature from the authentication responder who has authenticated the authentication initiator by verifying the initiator signature information; and the authentication initiator verifies the responder signature to authenticate the authentication responder.

## Claims

### Claim 1

A method for performing re-authentication between an authentication initiator and an authentication responder each holding an encryption key through an existing authentication procedure in a wireless power transfer system, the method comprising:
transmitting, by the authentication initiator, an authentication request message including an initiator digest encrypted using the encryption key to the authentication responder;
receiving, by the authentication initiator, an authentication response message including a responder digest encrypted using the encryption key from the authentication responder which authenticates the authentication initiator by decrypting the encrypted initiator digest with the encryption key; and
authenticating, by the authentication initiator, the authentication responder by decrypting the encrypted responder digest with the encryption key,
wherein the authentication request message further includes an initiator timestamp encrypted with the encryption key,
wherein the authentication response message further includes a responder timestamp encrypted with the encryption key,
wherein the authentication initiator authenticates the authentication responder by decrypting the encrypted responder type stamp together with the encrypted responder digest with the encryption key, and
wherein a value of the responder timestamp is a value of the initiator timestamp plus one.

### Claim 2

A method for performing re-authentication between an authentication initiator and an authentication responder each holding an encryption key through the existing authentication procedure in a wireless power transfer system, the method comprising:
receiving, by the authentication responder, an authentication request message including an initiator digest encrypted using the encryption key to the authentication initiator;
authenticating, by the authentication responder, the authentication initiator by decrypting the encrypted responder digest with the encryption key; and
transmitting, by the authentication responder, an authentication response message including a responder digest encrypted using the encryption key to the authentication initiator,
wherein the authentication request message further includes an initiator timestamp encrypted with the encryption key,
wherein the authentication response message further includes a responder timestamp encrypted with the encryption key,
wherein the authentication responder authenticates the authentication initiator by decrypting the initiator timestamp together with the encrypted initiator digest, and
wherein a value of the responder timestamp is a value of the initiator timestamp plus one.