# US 2013/0156181 A1 · Apparatus and method for generating secret key using change in wireless channel on wireless communication network > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0156181 A1 - Document ID: US20130156181A1 - Status: Published application - Kind: A1 - Application number: 13/602,225 - Filed: 2012-09-03 - Published: 2013-06-20 - Earliest claimed: 2011-12-14 - Assignees: Electronics and Telecommunications Research Institute - Inventors: Seon-Yeob BAEK; Sang-Kyung YOO; Seok RYU; Sang-Han LEE; Jang-Hong YOON - Web page: https://patentgrep.com/patent/US20130156181A1 ## CPC - H04L 9/0875: {based on channel impulse response [CIR]} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A secret key generation apparatus and method are provided. The secret key generation apparatus includes at least one antenna, amplification/phase controllers, a transceiver, and a random sign& controller. The antenna receives a wireless signal from a counterpart terminal that performs wireless communication. The amplification/phase controllers control the amplification gain and phase of the wireless signal that is received via at least one antenna. The transceiver measures the status of a wireless channel using the wireless signal having the controlled amplification gain and phase, determines parameters based on results of the measurement, and generates a secret key based on results of the determination. The random signal controller controls the amplification/phase controllers so that the amplification gain and phase are adjusted whenever the transceiver generates a secret key. ## Claims ### Claim 1 A secret key generation apparatus comprising: an at least one antenna configured to receive a wireless signal from a counterpart terminal that performs wireless communication; amplification/phase controllers configured to control amplification gain and phase of the wireless signal that is received via at least one antenna; a transceiver configured to measure status of a wireless channel using the wireless signal having the controlled amplification gain and phase, to determine parameters based on results of the measurement, and generate a secret key based on results of the determination; and a random signal controller configured to control the amplification/phase controllers so that the amplification gain and phase are adjusted whenever the transceiver generates a secret key. ### Claim 2 (depends on 1) The secret key generation apparatus as set forth in claim 1, wherein the transceiver comprises: transmission/reception controller configured to perform control so that the secret key generation apparatus operates in transmitter mode or receiver mode; and a key generation controller configured to control the parameters that are used to generate the secret key. ### Claim 3 (depends on 2) The secret key generation apparatus as set forth in claim 2, wherein the transceiver further comprises a receiver configured to generate the secret key using the wireless signal having the controlled amplification gain and phase when receiver mode is set by a switch that is controlled by the transmission/reception controller. ### Claim 4 (depends on 3) The secret key generation apparatus as set forth in claim 3, wherein the receiver comprises: a wireless channel information collection unit configured to receive the wireless signal having the controlled amplification gain and phase via the switch; a sample collection unit configured to extract information about the wireless channel including the amplification gain and phase by applying the wireless signal having the controlled amplification gain and phase to a predetermined sampling rate, and to generate quantization information by performing a quantization process; a wireless channel estimation unit configured to estimate a change in the wireless channel using the information about the wireless channel; and a key generation unit configured to generate the secret key using the quantization information. ### Claim 5 (depends on 2) The secret key generation apparatus as set forth in claim 2, wherein the transceiver further comprises a transmitter configured to send the wireless signal via the at least one antenna when the transmitter mode is set by a switch that is controlled by the transmission/reception controller. ### Claim 6 (depends on 2) The secret key generation apparatus as set forth in claim 2, wherein the key generation controller determines whether to perform key pairing that determines whether the secret key or a hash value derived from the secret key s identical with a secret key or a hash value generated by the counterpart terminal, and controls the parameters based on results of the key pairing. ### Claim 7 (depends on 6) The secret key generation apparatus as set forth in claim 6, wherein the transceiver further comprises a key exchange information collection unit configured to collect and store the results of the key pairing when the key generation controller performs the key pairing. ### Claim 8 A secret key generation method comprising: performing frame synchronization with a counterpart terminal that performs wireless communication; receiving a wireless signal from the counterpart terminal, and measuring long-period wireless channel status from the wireless signal; determining parameters to be used to generate a secret key while taking into consideration the long-period wireless channel status; changing a wireless channel response by controlling amplification gain and phase of the wireless signal, and measuring short-period wireless channel status based on the changed wireless channel response; and generating the secret key using the parameters in the short-period wireless channel status. ### Claim 9 (depends on 8) The secret key generation method as set forth in claim 8, further comprising determining whether to perform key pairing that determines whether the secret key or a hash value derived from the secret key is identical with a secret key or a hash value generated by the counterpart terminal. ### Claim 10 (depends on 9) The secret key generation method as set forth in claim 9, wherein the determining whether to perform the key pairing comprises: receiving the secret key or the hash value generated by the counterpart terminal; it as a result of the determination, it is determined that the secret key or the hash value derived from the secret key is identical with the secret key or the hash value generated by the counterpart terminal, generating key determination intimation to provide notification that the secret key has been determined; and transferring the key determination information to the counterpart terminal. ### Claim 11 (depends on 9) The secret key generation method as set forth in claim 9, wherein the determining whether to perform the key pairing comprises: if, as a result of the determination, it is determined that the secret key or the hash value derived from the secret key is not identical with the secret key or the hash value generated by the counterpart terminal, generating key mismatch information to provide notification that the secret key or the hash value derived from the secret key is not identical with the secret key or the hash value generated by the counterpart terminal; and transferring the key mismatch information to the counterpart terminal. ### Claim 12 (depends on 11) The secret key generation method as set forth in claim 11, wherein the transferring the key mismatch information to the counterpart terminal comprises generating a secret key again by controlling the parameters using a predetermined error processing method. ### Claim 13 (depends on 8) The secret key generation method as set forth in claim 8, wherein the generating the secret key comprises controlling, the amplification gain and phase in a key generation cycle, with synchronization of the amplification gain and phase being fixed whenever a secret key is generated.