# US 9,521,546 B2 · Secure RF communication method, terminal and system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,521,546 B2 - Document ID: US9521546B2 - Status: Granted - Kind: B2 - Application number: 14/235,046 - Filed: 2012-08-28 - Published: 2014-11-27 - Granted: 2016-12-13 - Earliest claimed: 2011-08-29 - Assignees: Nationz Technologies Inc. - Applicants: Meixiang Li - Inventors: Meixiang Li - Web page: https://patentgrep.com/patent/US9521546B2 ## CPC - H04W 12/04: Key management, e.g. using generic bootstrapping architecture [GBA] - H04B 5/24: Inductive coupling - H04K 1/00: Secret communication - H04K 1/003: {by varying carrier frequency at or within predetermined or random intervals (H04K1/04 takes precedence)} - H04L 9/0827: {involving distinctive intermediate devices or communication paths (network architectures or network communication protocols using different networks H04L63/18)} - H04L 9/3215: {using a plurality of channels (network architectures or network communication protocols using different networks H04L63/18)} - H04L 63/18: {using different networks or channels, e.g. using out of band channels (cryptographic mechanisms or cryptographic arrangements for key distribution involving distinctive intermediate devices or communication paths H04L9/0827; cryptographic mechanisms or cryptographic arrangements for authentication using a plurality of channels H04L9/3215)} - H04W 12/02: Protecting privacy or anonymity, e.g. protecting personally identifiable information [PII] - H04L 2209/80: Wireless - H04W 12/12: Detection or prevention of fraud - H04W 12/47: using near field communication [NFC] or radio frequency identification [RFID] modules - H04W 12/79: Radio fingerprint - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04B: TRANSMISSION - H04K: SECRET COMMUNICATION; JAMMING OF COMMUNICATION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A method, terminal and secure RF communication system are provided. The method for radio frequency secure communication of the invention comprises: generating magnetic channel data, and transmitting the magnetic channel data via a magnetic channel; establishing a radio frequency link with a peer device which feeds back a response information of the magnetic channel data; generating first radio frequency data, encrypting the first radio frequency data using the magnetic channel data, and transmitting the encrypted first radio frequency data to the peer device via the radio frequency link; and/or receiving encrypted second radio frequency data transmitted by the peer device via the radio frequency link, and decrypting the encrypted second radio frequency data using the magnetic channel data. By the above technical solution, the invention avoids the risk that a preset key is intercepted or decrypted, and enhances the security of the radio frequency link data exchanging process. ## Claims ### Claim 1 A method for radio frequency secure communication, comprising: generating magnetic channel data, and transmitting the magnetic channel data to a peer device via a magnetic channel; establishing a radio frequency link with the peer device which feeds back response information of the magnetic channel data; generating first radio frequency data, and transmitting encrypted first radio frequency data to the peer device via the radio frequency link, wherein the first radio frequency data is encrypted using the magnetic channel data; and receiving encrypted second radio frequency data transmitted by the peer device via the radio frequency link and decrypting the encrypted second radio frequency data using the magnetic channel data; wherein establishing a radio frequency link with a peer device which feeds back response information of the magnetic channel data includes: based on the magnetic channel data, calculating parameters of the radio frequency channel; and based on the parameters of the radio frequency channel, receiving the response information of the magnetic channel data fed back from the peer device on a corresponding radio frequency channel; and wherein the parameters of the radio frequency channel include an RF frequency point and a radio frequency address. ### Claim 2 (depends on 1) The method according to claim 1, wherein: the first radio frequency data is application data; and the second radio frequency data is response data of the application data. ### Claim 3 (depends on 1) The method according to claim 1, wherein: the magnetic channel data is generated randomly. ### Claim 4 A method for radio frequency secure communication, comprising: receiving magnetic channel data via a magnetic channel; establishing a radio frequency link with a peer device which sends the magnetic channel data; generating third radio frequency data, encrypting the third radio frequency data using the magnetic channel data, and transmitting the encrypted third radio frequency data to the peer device via the radio frequency link; and receiving encrypted fourth radio frequency data transmitted by the peer device via the radio frequency link, and decrypting the encrypted fourth radio frequency data using the magnetic channel data; wherein establishing a radio frequency link with a peer device which transmits the magnetic channel data includes: based on the received magnetic channel data, calculating parameters of the radio frequency channel; and based on the parameters of the radio frequency channel, sending the response information of the magnetic channel data to the peer device on a corresponding radio frequency channel; and wherein the parameters of the radio frequency channel include an RF frequency point and a radio frequency address. ### Claim 5 (depends on 4) The method according to claim 4, before calculating parameters of the radio frequency channel based on the magnetic channel data, further including: detecting magnetic signal strength of the magnetic channel data; determining whether the detected magnetic signal strength is greater than a preset value; and if the detected magnetic signal strength is greater than the preset value, based on the received magnetic channel data, calculating parameters of the radio frequency channel. ### Claim 6 (depends on 4) The method according to claim 4, wherein: the fourth radio frequency data is application data; and the third radio frequency data is response data of the application data. ### Claim 7 A terminal, comprising: a magnetic signal generator configured to generate magnetic channel data and to transmit the magnetic channel data via a magnetic channel; a radio frequency transceiver configured to establish a radio frequency link with a peer device which feeds back response information of the magnetic channel data, to transmit encrypted first radio frequency data to the peer device via the radio frequency link, and to receive encrypted second radio frequency data transmitted by the peer device via the radio frequency link; and a controller configured to generate the first radio frequency data, to encrypt the first radio frequency data using the magnetic channel data, to transmit the encrypted first radio frequency data to the radio frequency transceiver, and to decrypt the encrypted second radio frequency data using the magnetic channel data; wherein establishing a radio frequency link with a peer device which transmits the magnetic channel data includes: based on the received magnetic channel data, calculating parameters of the radio frequency channel; and based on the parameters of the radio frequency channel, sending the response information of the magnetic channel data to the peer device on a corresponding radio frequency channel; and wherein the parameters of the radio frequency channel include an RF frequency point and a radio frequency address. ### Claim 8 (depends on 7) The terminal according to claim 7, wherein: the magnetic signal generator includes a magnetic channel data generator and a magnetic signal generator; the magnetic channel data generator is configured to generate the magnetic channel data; and the magnetic signal generator is configured to transmit the magnetic channel data via the magnetic channel. ### Claim 9 (depends on 7) The terminal according to claim 7, wherein: controller the application is further configured to: generate the first radio frequency data, transmit the first radio frequency data, and to perform a corresponding applied process to the decrypted second radio frequency data; and the encryption and decryption encrypt the first radio frequency data using the magnetic channel data, to transmit the encrypted first radio frequency data to the radio frequency transceiver, to decrypt the encrypted second radio frequency data transmitted by the peer device using the magnetic channel data, and to transmit the decrypted second radio frequency data. ### Claim 10 A terminal, comprising: a magnetic inductor configured to receive magnetic channel data sent from outside via a magnetic channel; a radio frequency transceiver configured to establish a radio frequency link with a peer device which transmits the magnetic channel data, to transmit the encrypted third radio frequency data to the peer device via the radio frequency link, and receive the encrypted fourth radio frequency data transmitted by the peer device via the radio frequency link; and a controller configured to generate the third radio frequency data, to encrypt the third radio frequency data using the magnetic channel data, to transmit the encrypted third radio frequency data to the radio frequency transceiver, and to decrypt the encrypted fourth radio frequency data using the magnetic channel data; wherein establishing a radio frequency link with a peer device which transmits the magnetic channel data includes: based on the received magnetic channel data, calculating parameters of the radio frequency channel; and based on the parameters of the radio frequency channel, sending the response information of the magnetic channel data to the peer device on a corresponding radio frequency channel; and wherein the parameters of the radio frequency channel include an RF frequency point and a radio frequency address. ### Claim 11 (depends on 10) The terminal according to claim 10, wherein: the controller is further configured to: detect magnetic signal strength of the magnetic channel data; the determine whether the detected magnetic signal strength is greater than a preset value; and the transformation based on the magnetic channel data, calculate the parameters of the radio frequency channel when it is determined that the magnetic signal strength is greater than the preset value. ### Claim 12 (depends on 10) The terminal according to claim 10, wherein: controller the application is further configured to: generate the third radio frequency data, to transmit the third radio frequency data, and to perform a corresponding applied process to decrypted fourth radio frequency data; and the encryption and decryption after encrypting the third radio frequency data using the magnetic channel data, transmit the encrypted third radio frequency data to the radio frequency transceiver, to decrypt the encrypted fourth radio frequency data transmitted by the peer device using the magnetic channel data, and to transmit the decrypted data. ### Claim 13 (depends on 7, 10) A secure RF communication system, comprising: at least one first terminal according to claim 7; and at least one second terminal according to claim 10, wherein the first terminal and the second terminal transmit magnetic channel data via a magnetic channel, and decrypt and encrypt the radio frequency data transmitted on the radio frequency link between the first terminal and the second terminal using the magnetic channel data. ### Claim 14 (depends on 13) The system according to claim 13, wherein: the first terminal is a card reader, and the second terminal is a terminal with a built-in radio frequency card; the RF card is one of a radio frequency SIM card or a radio frequency SD card.