JP6896355B2 - Wireless transmitter, wireless receiver, wireless transmitter and wireless receiver - Google Patents

Description

The present invention relates to a radio transmission device, a radio reception device, a radio transmission method and a radio reception method.

Digital wireless communication systems encrypt voice data in order to conceal communication. In the conventional digital wireless communication system, a plurality of common keys for encryption are held, and the confidentiality is improved by switching the common keys. In the shared key cryptosystem, in order to use the same common key on the transmitting side and the receiving side, it is necessary to send the common key information from the transmitting side to the receiving side, and it is added to the voice data and the error correction code data. There was something. (See, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2008-172630

In the conventional digital wireless communication system, the voice-coded data and the error detection-encrypted data are encrypted by the same encryption method and the same common key as in Patent Document 1. Therefore, since the correctness of the common key can be discriminated from the decrypted voice-coded data and the error detection coded data, there is a problem that 100% search of the common key becomes easy.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a wireless transmission device, a wireless reception device, a wireless transmission method, and a wireless reception method that perform more secure encryption or decryption. To do.

The wireless transmission device according to the present invention is a common key holding unit that holds a first common key and a second common key that is different from the first common key and is paired with the first common key. An error detection from the voice data acquisition unit that acquires voice data, the voice encryption unit that encrypts the voice data using the first common key and generates voice encryption data, and the voice encryption data. An error detection code calculation unit that calculates the code, an error detection code conversion unit that converts the error detection code using the second common key to generate error detection code conversion data, and voice-encrypted data and error detection. A transmission unit that wirelessly transmits data including code conversion data is provided, and the second common key is the key number of the first common key, and the first common key is from the second common key. Not directly generated, the error detection code conversion unit includes an exclusive logical sum calculation unit, and the exclusive logical sum calculation unit calculates the exclusive logical sum of the error detection code and the key number of the first common key. Then, it becomes the error detection code conversion data.

The wireless receiving device according to the present invention is a common key holding unit that holds a third common key and a fourth common key that is different from the third common key and is paired with the third common key. A voice encryption / decryption unit that wirelessly receives data including voice encryption data and error detection code conversion data from a wireless transmission device, and voice encryption / decryption that decrypts voice data from voice encryption data using a third common key. The error detection code decoding unit that decodes the error detection code from the error detection code conversion data using the fourth common key, and the error detection code calculation unit that calculates the error detection code from the received voice encryption data. , And the fourth common key is the key number of the third common key, the third common key is not directly generated from the fourth common key, and the error detection code decoding unit is exclusive. The logical sum calculation unit is provided, and the exclusive logical sum calculation unit calculates the exclusive logical sum of the error detection code conversion data and the key number of the third common key to decode the error detection code.

The wireless transmission method according to the present invention includes a step of holding a first common key and a second common key that is different from the first common key and is paired with the first common key, and voice. A step of acquiring data, a step of encrypting voice data using the first common key to generate voice encrypted data, a step of calculating an error detection code from the voice encrypted data, and a second step. A second step is to generate error detection code conversion data by converting the error detection code using a common key, and to wirelessly transmit data including voice encryption data and error detection code conversion data. The common key is the key number of the first common key, the first common key is not directly generated from the second common key, and the step of generating the error detection code conversion data is the error detection code. This is a step of generating error detection code conversion data by calculating an exclusive logical sum with the key number of the first common key.

The wireless reception method according to the present invention includes a step of holding a third common key, a fourth common key that is different from the third common key and is paired with the third common key, and voice. A step of wirelessly receiving data including encrypted data and error detection code conversion data, a step of decrypting voice data from voice encrypted data using a third common key, and a step of using a fourth common key. The fourth common key is the key number of the third common key, which includes a step of decoding the error detection code from the error detection code conversion data and a step of calculating the error detection code from the received voice encryption data. Yes, the third common key is not directly generated from the fourth common key, and the step of decoding the error detection code is exclusive between the error detection code conversion data and the key number of the third common key. This is the process of calculating the logical sum and decoding the error detection code.

In the wireless transmission device and wireless transmission method according to the present invention, an error detection code is calculated for the voice encrypted data obtained by encrypting the voice data, and the error detection code is used as a common key for encrypting the voice data. Convert using a common key different from. Therefore, as compared with the case where the voice data and the error detection code are encrypted with the same common key, the risk of decryption by searching all the common keys is reduced, and the security of wireless communication is improved.

In the wireless receiving device and the wireless receiving method according to the present invention, the error detection code conversion data in which the error detection code is converted is decrypted with a common key different from the common key used for decrypting the voice encrypted data. Therefore, compared to the case where the voice encrypted data and the error detection code conversion data are decrypted with the same common key, the risk of decryption by searching all the common keys is reduced, so that the security of wireless communication is improved. improves. Further, the common key used by the wireless receiver for decoding is correct by determining whether the error detection code decoded from the error detection code conversion data and the error detection code calculated from the voice encrypted data match. It is possible to determine.

Objectives, features, aspects, and advantages of the present invention will be more apparent with the following detailed description and accompanying drawings.

It is a figure which shows the structure of the wireless communication system which concerns on Embodiment 1. FIG. It is a block diagram of the wireless transmission device which concerns on Embodiment 1. FIG. It is a block diagram of the error detection code conversion part of the wireless transmission device which concerns on Embodiment 1. FIG. It is a figure which shows the information held by the common key holding part of the wireless transmission device which concerns on Embodiment 1. FIG. It is a block diagram of the voice encryption part of the wireless transmission device which concerns on Embodiment 1. FIG. It is a hardware block diagram of the wireless transmission device which concerns on Embodiment 1. FIG. It is a hardware block diagram of the wireless transmission device which concerns on Embodiment 1. FIG. It is a flowchart which shows the operation of the wireless transmission apparatus which concerns on Embodiment 1. FIG. It is a block diagram of the wireless reception device which concerns on Embodiment 1. FIG. FIG. 5 is a block diagram of an error detection code decoding unit of the wireless receiver according to the first embodiment. It is a hardware block diagram of the wireless receiver device which concerns on Embodiment 1. FIG. It is a hardware block diagram of the wireless receiver device which concerns on Embodiment 1. FIG. It is a flowchart which shows the operation of the wireless receiver device which concerns on Embodiment 1. FIG. It is a figure which shows the encryption key list held by the common key holding part of the wireless receiving apparatus which concerns on Embodiment 1. FIG. It is a block diagram of the wireless receiver device which concerns on the modification of Embodiment 1. FIG. It is a block diagram of the wireless transmission device which concerns on Embodiment 2. FIG. It is a figure which shows the information which the common key holding part of the wireless transmission device which concerns on Embodiment 2 holds. It is a block diagram of the wireless receiver device which concerns on Embodiment 2. FIG. It is a figure which shows the encryption key list held by the common key holding part of the wireless receiving device which concerns on Embodiment 2. FIG. It is a block diagram of the wireless receiver device which concerns on 1st modification of Embodiment 2. It is a block diagram of the wireless transmission device which concerns on the 2nd modification of Embodiment 2. It is a block diagram of the wireless receiver device which concerns on the 2nd modification of Embodiment 2.

<Embodiment 1>
<Configuration of wireless transmitter>
FIG. 1 is a configuration diagram of a wireless communication system according to the first embodiment of the invention. The base station 6A and the base station 7B are connected by a wired line. Each of the base station 6A and the base station 7B is connected to the wireless device by a wireless line to transmit and receive a control signal and an audio signal. Area 9A indicates a communicable area of base station 6A, and area 9B indicates a communicable area of base station 7B.

The wireless device 1A is a terminal that performs voice communication, and the voice signal transmitted by the wireless device 1A is transmitted to the base station 6A, the wireless device 2B, and the like. Further, the audio signal transmitted to the base station 6A is transmitted to another wireless device 3C or the like. Further, the audio signal transmitted to the base station 6A is transmitted to the base station 7B via the wired line, and is transmitted to the wireless device 8B. The wireless device 3C or the like receives the audio signal transmitted by the wireless device 1A and reproduces the audio.

There are three types of wireless devices: devices that transmit and receive wirelessly, devices that only transmit wirelessly, and devices that only receive wirelessly. For example, the wireless device 3C is equipped with both a wireless transmitting device 10 and a wireless receiving device 20, and can transmit and receive voice. The wireless device 4D is equipped with only the wireless transmission device 10, and can transmit voice but cannot receive voice. The wireless device 5E is equipped with only the wireless receiving device 20, and can receive audio but cannot transmit audio.

FIG. 2 is a block diagram of the wireless transmission device 10 of the first embodiment. Further, FIG. 3 is a block diagram of an error detection code conversion unit 15 provided in the wireless transmission device 10. As shown in FIG. 2, the wireless transmission device 10 includes a common key holding unit 11, a voice data acquisition unit 12, a voice encryption unit 13, an error detection code calculation unit 14, an error detection code conversion unit 15, and a transmission unit 16. ..

The common key holding unit 11 holds the first common key K11 and the second common key K12. The first and second common keys K11 and K12 are a set. In the first embodiment, the second common key K12 is the key number of the first common key K11. In the first embodiment, the second common key K12 is also described as the key number K12 of the first common key K11. The first common key K11 is a common key used for encryption by a shared key encryption method such as DES (Data Encryption Standard), AES (Advanced Encryption Standard), and Camellia. The first common key K11 is a block cipher key having a block length of 64 bits or more.

FIG. 4 is a diagram showing information held by the common key holding unit 11. As shown in FIG. 4, the common key holding unit 11 holds an encryption key "WWWWWWWW" having a key number of "12" and an encryption method of "method A". In the first embodiment, the encryption key "WWWWWWWW" is the first common key K11, and the key number "12" is the second common key K12. Note that "WWWWWWWW" is a notation that schematically indicates an encryption key, and does not indicate an actual encryption key.

The audio data acquisition unit 12 includes a microphone 121, an A / D (Analog to digital) conversion unit 122, and an audio compression unit 123. The A / D conversion unit 122 converts the analog voice acquired from the microphone into digital data. The voice compression unit 123 compresses the digitally converted voice by voice coding to generate the voice data 301.

The voice encryption unit 13 generates the voice encryption data 303 by encrypting the voice data 301 output from the voice data acquisition unit 12 using the first common key K11. Here, the voice encryption unit 13 includes a selector 131 as shown in FIG. The voice encryption unit 13 refers to the common key holding unit 11 and selects the encryption method associated with the first common key K11 from the plurality of encryption methods A, B, and C by the selector 131. To do. The error detection code calculation unit 14 calculates the error detection code 304 from the voice encrypted data 303. The error detection code 304 is, for example, CRC (Cyclic Redundancy Check) or the like.

The error detection code conversion unit 15 converts the error detection code 304 using the second common key K12 (that is, the key number K12 of the first common key K11) to generate the error detection code conversion data 306. As shown in FIG. 3, in the first embodiment, the error detection code conversion unit 15 includes an exclusive OR calculation unit 151. The exclusive OR calculation unit 151 calculates the exclusive OR of the error detection code 304 and the second common key K12 (that is, the key number K12 of the first common key K11) to calculate the error detection code 304. Is converted to generate error detection code conversion data 306.

The transmission unit 16 wirelessly transmits data including voice encryption data 303 and error detection code conversion data 306. The transmission unit 16 includes a modulation unit 161, an RF (radio frequency) unit 162, and an antenna 163. The modulation unit 161 modulates the voice encryption data 303 and the error detection code conversion data 306. The RF unit 162 wirelessly converts the modulation data output from the modulation unit 161 and outputs it as a radio wave from the antenna 163.

FIG. 6 is a hardware configuration diagram of the wireless transmission device 10. Each function of the common key holding unit 11, the voice data acquisition unit 12, the voice encryption unit 13, the error detection code calculation unit 14, the error detection code conversion unit 15, and the transmission unit 16 in the wireless transmission device 10 is realized by the processing circuit HW11. Will be done. Some functions of the voice data acquisition unit 12 are realized by the microphone 121. Some functions of the transmitter 16 are realized by the antenna 163. Some functions of the common key holding unit 11 are realized by the storage device HW12. The wireless transmission device 10 holds the first common key K11 and the second common key K12 paired with the first common key K11, acquires voice data 301, and uses the first common key K11. The voice data 301 is encrypted using the voice data 301 to generate the voice encrypted data 303, the error detection code 304 is calculated from the voice encrypted data 303, and the error detection code 304 is converted using the second common key K12. A processing device for generating the error detection code conversion data 306 and transmitting the data including the voice encryption data 303 and the error detection code conversion data 306 is provided. The processing circuit HW11 is a CPU (Central Processing Unit, central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor, DSP (Digital)) that executes a program stored in a memory even if it is dedicated hardware. It may also be called a Signal Processor).

When the processing circuit HW11 is dedicated hardware, the processing circuit HW11 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), or an FPGA (Field-Programmable). Gate Array), or a combination of these. The functions of the common key holding unit 11, the voice data acquisition unit 12, the voice encryption unit 13, the error detection code calculation unit 14, the error detection code conversion unit 15, and the transmission unit 16 may be realized by the processing circuit. , The functions of each part may be integrated into one processing circuit.

When the processing circuit HW11 is the processor HW13, the functions of the common key holding unit 11, the voice data acquisition unit 12, the voice encryption unit 13, the error detection code calculation unit 14, the error detection code conversion unit 15, and the transmission unit 16 are , Software, etc. (software, firmware or software and firmware). The software or the like is described as a program and stored in the memory HW14. As shown in FIG. 7, the processor HW13 applied to the processing circuit HW11 realizes the functions of each part by reading and executing the program stored in the memory HW14. That is, when the wireless transmission device 10 is executed by the processing circuit HW11, the step of holding the first common key K11 and the second common key K12 paired with the first common key K11, voice. A step of acquiring the data 301, a step of encrypting the voice data 301 using the first common key K11 to generate the voice encrypted data 303, and a step of calculating the error detection code 304 from the voice encrypted data 303. The step of converting the error detection code 304 using the second common key K12 to generate the error detection code conversion data 306, and the step of transmitting the data including the voice encryption data 303 and the error detection code conversion data 306 are A memory HW14 for storing a program to be executed as a result is provided. Further, these programs execute the procedures and methods of the common key holding unit 11, the voice data acquisition unit 12, the voice encryption unit 13, the error detection code calculation unit 14, the error detection code conversion unit 15, and the transmission unit 16 on the computer. It can be said that it is something that makes you. The memory HW14 and the storage device HW12 include, for example, RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), and the like. It may be a non-volatile or volatile semiconductor memory, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD (Digital Versatile Disc), or any storage medium that will be used in the future.

Note that some of the functions of the common key holding unit 11, the voice data acquisition unit 12, the voice encryption unit 13, the error detection code calculation unit 14, the error detection code conversion unit 15, and the transmission unit 16 are provided with dedicated hardware. It may be realized and partly realized by software or firmware. As described above, the processing circuit HW11 can realize each of the above-mentioned functions by hardware, software, firmware, or a combination thereof.

<Operation of wireless transmitter>
FIG. 8 is a flowchart showing the operation of the wireless transmission device 10. In the wireless transmission device 10, the common key holding unit 11 holds the first common key K11 and the second common key K12 paired with the first common key K11 (step S101). Next, the voice data acquisition unit 12 acquires the voice data 301 (step S102). Then, the voice encryption unit 13 encrypts the voice data 301 using the first common key K11 to generate the voice encrypted data 303 (step S103). A shared key cryptographic algorithm such as DES, AES, or Camellia is used to encrypt the voice data 301.

Next, the error detection code calculation unit 14 calculates the error detection code 304 from the voice encrypted data 303 (step S104). Next, the error detection code conversion unit 15 converts the error detection code 304 using the second common key K12 (that is, the key number K12 of the first common key K11), and the error detection code conversion data 306. Is generated (step S105). Then, the transmission unit 16 wirelessly transmits data including the voice encrypted data 303 and the error detection code conversion data 306 (step S106).

<Configuration of wireless receiver>
FIG. 9 is a block diagram of the wireless receiver 20 according to the first embodiment. Further, FIG. 10 is a block diagram of an error detection code decoding unit 24 provided in the wireless receiving device 20. As shown in FIG. 9, the wireless receiving device 20 includes a common key holding unit 21, a receiving unit 22, a voice encryption decoding unit 23, an error detection code decoding unit 24, an error detection code calculation unit 25, and an error detection code matching determination unit 26. To be equipped.

In the wireless receiving device 20, the common key holding unit 21 holds a third common key K13 and a fourth common key K14. The third and fourth common keys K13 and K14 are a set. In the first embodiment, the fourth common key K14 is the key number of the third common key K13. In the first embodiment, the fourth common key K14 is also described as the key number K14 of the third common key K13. The third common key K13 is a common key used for encryption by a shared key cryptosystem such as DES, AES, or Camellia. The third common key K13 is a block cipher key having a block length of 64 bits or more. In the first embodiment, it is assumed that the common key holding unit 21 holds the same information as the information held by the common key holding unit 11 (FIG. 4).

The receiving unit 22 includes an antenna 221 and an RF unit 222 and a demodulation unit 223. The RF unit 222 converts the radio wave received by the antenna 221 to obtain the modulated data. The demodulation unit 223 demodulates the modulation data to obtain the voice encryption data 402 and the error detection code conversion data 401 wirelessly transmitted from the wireless transmission device 10.

The voice encryption / decryption unit 23 decrypts the voice data 41 from the voice encryption data 402 by using the third common key K13. Further, the error detection code calculation unit 25 calculates the error detection code 405 from the voice encryption data 402.

When the third common key K13 used in the voice encryption / decryption unit 23 is the same key (that is, the same key) as the first common key K11 used in the wireless transmission device 10, the wireless reception device 20 Can correctly decrypt the voice encrypted data 402 received from the wireless transmission device 10.

The error detection code decoding unit 24 decodes the error detection code 404 from the error detection code conversion data 401 by using the fourth common key K14 (that is, the key number K14 of the third common key K13). As shown in FIG. 8, in the first embodiment, the error detection code decoding unit 24 includes an exclusive OR calculation unit 241. The exclusive OR calculation unit 241 calculates the exclusive OR of the error detection code conversion data 401 and the fourth common key K14 (that is, the key number K14 of the third common key K13) to detect an error. Generate reference numeral 404.

The error detection code matching determination unit 26 determines whether or not the error detection code 404 decoded from the error detection code conversion data 401 and the error detection code 405 calculated from the voice encryption data 402 match. If they do not match, the error detection code matching determination unit 26 determines that the fourth common key K14 is the common key used when converting the error detection code in the wireless transmitter 10 (that is, the second common key K12). Is determined to be different from the above, and a determination result signal 408 indicating a match or a mismatch is output.

Further, the decoded audio data 41 is output to the output unit 27. The output unit 27 includes an audio restoration unit 271, a D / A (Digital to analogue) conversion unit 272, and a speaker 273. The audio restoration unit 271 restores the compression of the audio data 41. Then, the D / A conversion unit 272 converts the digital data into analog voice and outputs it to the speaker 273.

FIG. 11 is a hardware configuration diagram of the wireless receiver 20. The functions of the common key holding unit 21, the receiving unit 22, the voice encryption / decoding unit 23, the error detection code decoding unit 24, the error detection code calculation unit 25, and the error detection code matching determination unit 26 in the wireless receiver 20 are the processing circuit HW21. Is realized by. Some functions of the receiving unit 22 are realized by the antenna 221. Some functions of the common key holding unit 21 are realized by the storage device HW22. The wireless receiving device 20 holds a third common key K13 and a fourth common key K14 paired with the third common key K13, and includes voice encryption data 402 and error detection code conversion data 401. Data is wirelessly received, the voice data 41 is decrypted from the voice encrypted data 402 using the third common key K13, and the error detection code 404 from the error detection code conversion data 401 using the fourth common key K14. The error detection code 405 calculated from the received voice encryption data 402 is obtained, and the error detection code 404 decrypted from the error detection code conversion data 401 and the error detection code 405 calculated from the voice encryption data 402 are A processing device for determining whether or not they match is provided. The processing circuit HW21 is a CPU (Central Processing Unit, central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor, DSP (Digital)) that executes a program stored in a memory even if it is dedicated hardware. It may also be called a Signal Processor).

When the processing circuit HW21 is dedicated hardware, the processing circuit HW21 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), or an FPGA (Field-Programmable). Gate Array), or a combination of these. Even if the functions of the common key holding unit 21, the receiving unit 22, the voice encryption / decoding unit 23, the error detection code decoding unit 24, the error detection code calculation unit 25, and the error detection code match determination unit 26 are realized by the processing circuit. Alternatively, the functions of each part may be integrated into one processing circuit.

When the processing circuit HW21 is the processor HW23, each part of the common key holding unit 21, the receiving unit 22, the voice encryption decoding unit 23, the error detection code decoding unit 24, the error detection code calculation unit 25, and the error detection code matching determination unit 26. The function is realized by a combination of software and the like (software, firmware or software and firmware). The software or the like is described as a program and stored in the memory HW24. As shown in FIG. 12, the processor HW23 applied to the processing circuit HW21 realizes the functions of each part by reading and executing the program stored in the memory HW24. That is, when the wireless receiving device 20 is executed by the processing circuit HW21, the step of holding the third common key K13 and the fourth common key K14 combined with the third common key K13, voice. A step of wirelessly receiving data including encrypted data 402 and error detection code conversion data 401, a step of decrypting voice data 41 from voice encrypted data 402 using a third common key K13, a fourth common key K14. The step of decoding the error detection code 404 from the error detection code conversion data 401 using the error detection code conversion data 401, the step of calculating the error detection code 405 from the received voice encryption data 402, and the error detection code 404 decoded from the error detection code conversion data 401. And the memory HW24 for storing the program for which the step of determining whether or not the error detection code 405 calculated from the voice encrypted data 402 matches is executed as a result is provided. In addition, these programs computerize the procedures and methods of the common key holding unit 21, the receiving unit 22, the voice encryption / decoding unit 23, the error detection code decoding unit 24, the error detection code calculation unit 25, and the error detection code matching determination unit 26. It can be said that it is to be executed by. The memory HW24 and the storage device HW22 include, for example, RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), and the like. It may be a non-volatile or volatile semiconductor memory, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD (Digital Versatile Disc), or any storage medium that will be used in the future.

Note that some of the functions of the common key holding unit 21, the receiving unit 22, the voice encryption / decoding unit 23, the error detection code decoding unit 24, the error detection code calculation unit 25, and the error detection code matching determination unit 26 are dedicated hardware. It may be realized by hardware and partly by software or firmware. As described above, the processing circuit HW21 can realize each of the above-mentioned functions by hardware, software, firmware, or a combination thereof.

<Operation of wireless receiver>
FIG. 13 is a flowchart showing the operation of the wireless receiving device 20. In the wireless receiving device 20, the common key holding unit 21 holds a third common key K13 and a fourth common key K14 paired with the third common key K13 (step S201). Next, the receiving unit 22 wirelessly receives the data including the voice encrypted data 402 and the error detection code conversion data 401 (step S202). Then, the voice encryption / decryption unit 23 decrypts the voice data 41 from the voice encryption data 402 using the third common key K13 (step S203). A cryptographic algorithm of a shared key cryptosystem such as DES, AES, or Camellia is used to decrypt the voice data 41.

Next, the error detection code decoding unit 24 decodes the error detection code 404 from the error detection code conversion data 401 using the fourth common key K14 (that is, the key number K14 of the third common key K13) (that is, the error detection code decoding unit 24 decodes the error detection code 404 from the error detection code conversion data 401. Step S204). Next, the error detection code calculation unit 25 calculates the error detection code 405 from the received voice encryption data 402 (step S205). Then, the error detection code matching determination unit 26 determines whether the error detection code 404 decoded from the error detection code conversion data 401 and the error detection code 405 calculated from the voice encryption data 402 match (step S206). ..

In the first embodiment, the information held in the common key holding unit 11 of the wireless transmitting device 10 (that is, the first and second common keys K11 and K13) and the common key holding of the wireless receiving device 20 The case where the information held in the unit 21 (that is, the third and fourth common keys K13 and K14) is the same has been described. Here, for example, as shown in FIG. 14, a plurality of combinations of the third common key K13 and the fourth common key K14 are described in the encryption key list held in the common key holding unit 21 of the wireless receiving device 20. Consider the case where it is done.

As shown in FIG. 14, when there are a plurality of combinations of the third common key K13 and the fourth common key K14, the error detection code decoding unit 24 uses each of the plurality of fourth common keys K14 to make an error. A plurality of error detection codes 404 are decoded from the detection code conversion data 401.

Next, the error detection code matching determination unit 26 determines whether each of the plurality of error detection codes 404 decoded from the error detection code conversion data 401 matches the error detection code 405 calculated from the voice encryption data 402. judge. Then, the error detection code matching determination unit 26 identifies the fourth common key K14 used for decoding the error detection code 404 that matches the error detection code 405 calculated from the voice encryption data 402. Then, the voice encryption / decryption unit 23 decrypts the voice data 41 from the voice encryption data 402 by using the third common key K13 which is paired with the specified fourth common key K14.

As described above, when the wireless receiving device 20 holds a plurality of combinations of the third common key K13 and the fourth common key K14, and it is unknown which common key set is used in the wireless transmitting device 10. It is also possible to identify the correct common key by trying all the fourth common keys K14 existing in the cryptographic key list in the wireless receiver 20.

<Effect>
The wireless transmission device 10 according to the first embodiment has a common key holding unit 11 that holds a first common key K11 and a second common key K12 that is paired with the first common key K11, and voice data. From the voice data acquisition unit 12 that acquires the 301, the voice encryption unit 13 that encrypts the voice data 301 using the first common key K11 and generates the voice encryption data 303, and the voice encryption data 303. An error detection code calculation unit 14 that calculates the error detection code 304, and an error detection code conversion unit 15 that converts the error detection code 304 using the second common key K12 to generate error detection code conversion data 306. , A transmission unit 16 that wirelessly transmits data including voice encrypted data 303 and error detection code conversion data 306.

In the wireless transmission device 10 and the wireless transmission method according to the first embodiment, an error detection code 304 is calculated for the voice encrypted data 303 that encrypts the voice data 301, and the error detection code 304 is used as the voice data 301. Convert using a common key that is different from the common key used for encryption. Therefore, compared to the case where the voice data 301 and the error detection code 304 are encrypted with the same common key, the risk of decryption by searching all the common keys is reduced, and the security of wireless communication is improved. To do.

Further, in the wireless transmission device 10 according to the first embodiment, the second common key K12 is the key number of the first common key K11, and the error detection code conversion unit 15 uses the exclusive OR calculation unit 151. The exclusive OR calculation unit 151 converts the error detection code 304 by calculating the exclusive OR of the error detection code 304 and the key number of the first common key K11, and performs error detection code conversion. Generate data 306. Therefore, since the processing time of the exclusive OR operation is short, it is possible to reduce the power consumption and include the information of the key number of the first common key K11 in the error detection code 304.

Further, the wireless receiving device 20 according to the first embodiment includes a common key holding unit 21 that holds a third common key K13 and a fourth common key K14 that is paired with the third common key K13. The voice data 41 is transmitted from the voice encryption data 402 by using the receiving unit 22 that wirelessly receives the data including the voice encryption data 402 and the error detection code conversion data 401 from the wireless transmission device 10 and the third common key K13. An error is detected from the voice encryption decoding unit 23 for decoding, the error detection code decoding unit 24 for decoding the error detection code 404 from the error detection code conversion data 401 using the fourth common key K14, and the received voice encryption data 402. An error detection code calculation unit 25 for calculating the detection code 405 is provided.

In the wireless receiving device 20 and the wireless receiving method according to the first embodiment, the error detection code conversion data 401 in which the error detection code is converted is used with a common key different from the common key used for decrypting the voice encrypted data 402. Decrypt. Therefore, as compared with the case where the voice encrypted data 402 and the error detection code conversion data 401 are decrypted with the same common key, the risk of decryption by searching all the common keys is reduced, so that the wireless communication is safe. Improves sex. Further, by determining whether the error detection code 404 decoded from the error detection code conversion data 401 and the error detection code 405 calculated from the voice encryption data 402 match, the wireless receiving device 20 uses the error detection code 20 for decoding. It is possible to determine whether the common key is correct.

Further, the wireless receiving device 20 according to the first embodiment determines whether the error detection code 404 decoded from the error detection code conversion data 401 and the error detection code 405 calculated from the voice encryption data 402 match. A detection code matching determination unit 26 is further provided, and the error detection code matching determination unit 26 when decoding the error detection code 404 from the error detection code conversion data 401 when the two error detection codes 404 and 405 do not match. It is determined that the fourth common key K14 used in the above is different from the common key (that is, the second common key K12) used when converting the error detection code in the wireless transmission device 10.

Therefore, by providing the error detection code matching determination unit 26, it is possible to determine whether the common key used by the wireless receiving device 20 for decoding is correct. If it is determined that the common key used by the wireless receiving device 20 for decoding is incorrect, the received signal is decoded by updating the common key held by the wireless receiving device 20 or trying a different common key. Can be continued.

Further, in the wireless receiving device 20 according to the first embodiment, the common key holding unit 21 may hold a plurality of combinations of the third common key K13 and the fourth common key K14. The error detection code decoding unit 24 decodes a plurality of error detection codes 404 from the error detection code conversion data 401 by using each of the plurality of fourth common keys K14, and the error detection code matching determination unit 26 decodes the error detection code matching determination unit 26. It is determined whether each of the plurality of error detection codes 404 decoded from the detection code conversion data 401 and the error detection code 405 calculated from the voice encryption data 402 match, and the error detection code match determination unit 26 determines whether the error detection code match determination unit 26 matches the voice. The fourth common key K14 used for decrypting the error detection code 404 that matches the error detection code 405 calculated from the encrypted data 402 is specified, and the voice encryption / decryption unit 23 identifies the specified fourth common. The voice data 41 is decrypted from the voice encrypted data 402 by using the third common key K13 which is paired with the key K14.

Therefore, even if the wireless receiving device 20 holds a plurality of combinations of the third common key K13 and the fourth common key K14 and it is unknown which common key set is used in the wireless transmitting device 10. The correct common key can be identified by trying all the fourth common keys K14 existing in the cryptographic key list in the wireless receiver 20.

Further, in the wireless receiving device 20 according to the first embodiment, the fourth common key K14 is the key number of the third common key K13, and the error detection code decoding unit 24 uses the exclusive OR calculation unit 241. The exclusive OR calculation unit 241 calculates the exclusive OR of the error detection code conversion data 401 and the key number of the third common key K13, and decodes the error detection code 404.

Therefore, since the processing time of the exclusive OR operation is short, it is possible to reduce the power consumption and decode the error detection code 404 from the error detection code conversion data 401. Even when trying to decode the error detection code 404 using a plurality of fourth common keys K14 (that is, the key number of the third common key K13), the exclusive OR operation has a short processing time. It is possible to suppress an increase in processing time and reduce power consumption.

<Modified Example of Embodiment 1>
FIG. 15 is a block diagram of the wireless receiver 20A according to the modified example of the first embodiment. The wireless receiving device 20A further includes a reception quality determination unit 28 and a common key updating unit 29 with respect to the wireless receiving device 20.

The reception quality determination unit 28 determines whether or not the reception quality exceeds a predetermined standard based on the radio wave intensity received by the RF unit 222 of the reception unit 22. When it is determined that the reception quality exceeds a predetermined standard and the error detection code matching determination unit 26 determines that the two error detection codes 404 and 405 do not match, the error detection code matching determination unit 26 26 determines that the fourth common key K14 is different from the common key (that is, the second common key K12) used when converting the error detection code 304 in the wireless transmission device 10. In this case, the error detection code match determination unit 26 outputs a determination result signal 408 indicating a mismatch to the common key update unit 29.

When it is determined that the fourth common key K14 is different from the second common key K12, that is, when the determination result signal 408 indicating a mismatch is received, the common key update unit 29 is the common key held by the common key holding unit 21. (That is, the third and fourth common keys K13 and K14) are updated.

The common key update unit 29 requests the wireless transmission device 10 to update the third and fourth common keys K13 and K14. Further, the common key update unit 29 may request the base station to update the third and fourth common keys K13 and K14 by wire or wirelessly.

The third and fourth common keys K13 and K14 may be manually updated by the user who has been notified or the like, in addition to being automatically updated via the wireless line or the wired line. When the user manually updates, there is a method using a storage medium such as a USB memory, and a method of obtaining a common key value via e-mail, telephone, or fax and inputting the value into the device. is there.

When the third and fourth common keys K13 and K14 are manually updated by the user, leakage of the common key can be prevented. That is, when the common key is transmitted via a wireless line or a wired line, the signal of the line may be intercepted and the common key may be leaked. There is no fear.

Further, the common key update unit 29 may display on a display or the like so that the user can select whether or not to update the common key before updating the common key. When the user chooses to update, the common key update unit 29 updates the common key.

<Effect>
The wireless receiver 20A in the modified example of the first embodiment further includes a reception quality determination unit 28 that determines the reception quality from the radio wave strength in the reception unit 22, and the reception quality in the reception unit 22 exceeds a predetermined standard. When it is determined that the error detection code matches, and the error detection code matching determination unit 26 determines that the two error detection codes 404 and 405 do not match, the fourth common key K14 sets the error detection code in the wireless transmission device 10. It is determined that the key is different from the common key used at the time of conversion (that is, the second common key K12).

Therefore, by considering the reception quality in the receiving unit 22, the fourth common key K14 and the common key used when converting the error detection code in the wireless transmission device 10 (that is, the second common key K12) It is possible to more accurately determine whether or not they are different.

Further, the wireless receiving device 20A in the modified example of the first embodiment further includes a common key updating unit 29, and the error detection code matching determination unit 26 has an error detection code matching determination unit 26, and the fourth common key K14 has an error detection code in the wireless transmitting device 10. When it is determined that the key is different from the common key used when converting (that is, the second common key K12), the common key update unit 29 updates the third common key K13 and the fourth common key K14. .. Therefore, if it is determined that the common key used by the wireless receiving device 20 for decoding is incorrect, the decoding process of the received signal can be continued by updating the common key held by the wireless receiving device 20. It will be possible.

In a system in which the common key is updated, problems such as a difference in update timing between the transmitting side and the receiving side are assumed. However, by providing the error detection code matching determination unit 26, the common key on the transmitting side and the receiving side is provided. It is possible to determine the match and the mismatch of. This makes it possible to facilitate system construction.

Further, in the wireless receiving device 20A in the modified example of the first embodiment, the common key updating unit 29 requests the wireless transmitting device 10 to update the third common key K13 and the fourth common key K14. Therefore, by making an update request to the wireless transmitting device 10 holding the correct common key, the wireless receiving device 20A can acquire the correct third common key K13 and the fourth common key K14. Is.

Further, in the wireless receiving device 20A in the modified example of the first embodiment, the common key updating unit 29 updates the third common key K13 and the fourth common key K14 based on the operation of the user. Therefore, it is possible to update the common key based on the judgment of the user.

<Embodiment 2>
<Configuration of wireless transmitter>
FIG. 16 is a block diagram of the wireless transmission device 30 according to the second embodiment. The error detection code conversion unit 15 of the wireless transmission device 10 (FIG. 2) in the first embodiment has an exclusive OR calculation unit 151 (FIG. 3), and is configured to perform an exclusive OR operation. On the other hand, the error detection code conversion unit 35 of the wireless transmission device 30 in the second embodiment uses the second common key K22, which will be described later, to make an error by a cryptographic algorithm of a shared key cryptosystem such as DES, AES, or Camellia. The detection code 304 is encrypted. That is, the error detection code conversion unit 35 of the wireless transmission device 30 in the second embodiment converts the error detection code 304 by encrypting the error detection code 304 to generate the error detection code conversion data 306.

In the wireless transmission device 30, the common key holding unit 11 holds the first common key K21 and the second common key K22. The first and second common keys K21 and K22 are a set. In the second embodiment, each of the first common key K21 and the second common key K22 is a block cipher key having a block length of 64 bits or more. Each of the first common key K21 and the second common key K22 is a common key used for encryption by a shared key cryptosystem such as DES, AES, or Camellia.

FIG. 17 is a diagram showing information held by the common key holding unit 11. As shown in FIG. 17, the common key holding unit 11 has the first common key K21 “WWWWWWWW” whose encryption method is “method A” and the encryption method “WWWWWWWW” as the group number 1 (No. 1). Method X ”The second common key K22“ KKKKKKKK ”is held. Note that "WWWWWWWW" and "KKKKKKKK" are notations that schematically indicate an encryption key, and do not indicate an actual encryption key.

Since the wireless transmission device 30 in the second embodiment includes the same configuration as the wireless transmission device 10 (FIG. 1), the same configuration is designated by the same reference numeral and has a common description. Is omitted.

<Operation of wireless transmitter>
In the wireless transmission device 30, the voice encryption unit 13 uses the first common key K21 to encrypt the voice data 302 output from the voice data acquisition unit 12 by a shared key encryption method such as DES, AES, or Camellia. Voice encrypted data 303 is generated by encrypting with an algorithm.

In the wireless transmission device 30, the error detection code conversion unit 35 uses the second common key K22 to encrypt the error detection code 304 by a cryptographic algorithm of a shared key cryptosystem such as DES, AES, or Camellia. Since the other operations of the wireless transmission device 30 are the same as those of the wireless transmission device 10 in the first embodiment, the description thereof will be omitted.

<Configuration of wireless receiver>
FIG. 18 is a block diagram of the wireless receiver 40 according to the second embodiment. The error detection code decoding unit 24 of the wireless receiver 20 (FIG. 9) according to the first embodiment has an exclusive OR calculation unit 241 (FIG. 10), and is configured to perform an exclusive OR operation. On the other hand, the error detection code decoding unit 44 of the wireless receiver 40 according to the second embodiment uses the fourth common key K24 described later, and makes an error by a cryptographic algorithm of a shared key cryptosystem such as DES, AES, or Camellia. The detection code 304 is encrypted.

In the wireless receiving device 40, the common key holding unit 21 holds a third common key K23 and a fourth common key K24. The first and second common keys K23 and K24 are a set. In the second embodiment, each of the third common key K23 and the fourth common key K24 is a block cipher key having a block length of 64 bits or more. Each of the third common key K23 and the fourth common key K24 is a common key used for encryption by a shared key cryptosystem such as DES, AES, or Camellia.

As shown in FIG. 17, the common key holding unit 21 in the wireless receiving device 40 holds the same information as the information held by the common key holding unit 11 in the wireless transmitting device 30. That is, the common key holding unit 21 has a third common key K23 "WWWWWWWW" whose encryption method is "method A" and a fourth common key K23 "WWWWWWWW" whose encryption method is "method X" as group number 1 (No. 1). The common key K24 "KKKKKKKK" is held. If the common key and the encryption method are different between the encryption in the wireless transmission device 30 and the decryption in the wireless reception device 40, the decryption cannot be performed correctly.

Since the wireless receiving device 40 in the second embodiment includes the same configuration as the wireless receiving device 20 (FIG. 9), the same reference numerals are given to the same configurations, and a common description is given. Is omitted.

<Operation of wireless receiver>
In the wireless receiving device 40, the voice encryption / decryption unit 23 decrypts the voice data 41 from the voice encryption data 402 by the encryption algorithm of the shared key encryption method such as DES, AES, Camellia, etc. using the third common key K23. To do.

In the wireless receiving device 40, the error detection code decoding unit 44 uses the fourth common key K24 to use the error detection code 404 from the error detection code conversion data 401 by a cryptographic algorithm of a shared key cryptosystem such as DES, AES, or Camellia. To decrypt. Since the other operations of the wireless receiving device 40 are the same as those of the wireless receiving device 20 in the first embodiment, the description thereof will be omitted.

In the second embodiment, the information held in the common key holding unit 11 of the wireless transmitting device 30 (that is, the first and second common keys K21 and K23) and the common key holding of the wireless receiving device 40 The case where the information held in the unit 21 (that is, the third and fourth common keys K23 and K24) is the same has been described. Here, for example, as shown in FIG. 19, a plurality of combinations of the third common key K23 and the fourth common key K24 are described in the encryption key list held in the common key holding unit 21 of the wireless receiving device 20. Consider the case where it is done.

As shown in FIG. 19, when there are a plurality of combinations of the third common key K23 and the fourth common key K24, the error detection code decoding unit 24 uses each of the plurality of fourth common keys K24 to make an error. A plurality of error detection codes 404 are decoded from the detection code conversion data 401.

Next, the error detection code matching determination unit 26 determines whether each of the plurality of error detection codes 404 decoded from the error detection code conversion data 401 matches the error detection code 405 calculated from the voice encryption data 402. judge. Then, the error detection code matching determination unit 26 identifies the fourth common key K24 used for decoding the error detection code 404 that matches the error detection code 405 calculated from the voice encryption data 402. Then, the voice encryption / decryption unit 23 decrypts the voice data 41 from the voice encryption data 402 by using the third common key K23 which is paired with the specified fourth common key K24.

As described above, when the wireless receiving device 40 holds a plurality of combinations of the third common key K23 and the fourth common key K24, and it is unknown which common key set is used in the wireless transmitting device 30. It is also possible to identify the correct common key by trying all the fourth common keys K24 existing in the cryptographic key list in the wireless receiving device 40.

<Effect>
In the wireless transmission device 30 according to the second embodiment, each of the first common key K21 and the second common key K22 is a block cipher key having a block length of 64 bits or more. In the wireless transmission device 30 according to the second embodiment, the voice data 301 is encrypted by a block cipher having a block length of 64 bits or more to obtain the voice encrypted data 303. Then, the error detection code 304 is calculated for the voice encrypted data 303, and the error detection code 304 is used as a common key different from the common key used for encrypting the voice data 301, and the block length is 64 bits. Encrypt with the above block cipher. Therefore, compared to the case where the voice data 301 and the error detection code 304 are encrypted with the same common key, the risk of decryption by searching all the common keys is reduced, and the security of wireless communication is improved. To do. Further, since the error detection code is encrypted by the fourth common key K24, it becomes impossible to decipher the first common key K21 from the error detection code, which has the effect of increasing the confidentiality of the third common key K23. Is obtained.

Further, in the wireless receiving device 40 according to the second embodiment, each of the third common key K23 and the fourth common key K24 is a block cipher key having a block length of 64 bits or more. In the wireless receiving device 40 according to the second embodiment, the error detection code conversion data 401 in which the error detection code is encrypted is used with a common key different from the common key used for decrypting the voice encrypted data 402. , Decrypt by block cipher with a block length of 64 bits or more. Therefore, as compared with the case where the voice encrypted data 402 and the error detection code conversion data 401 are decrypted with the same common key, the risk of decryption by searching all the common keys is reduced, so that the wireless communication is safe. Improves sex. Further, by determining whether the error detection code 404 decoded from the error detection code conversion data 401 and the error detection code 405 calculated from the voice encryption data 402 match, the wireless receiving device 40 uses it for decoding. It is possible to determine whether the common key is correct.

<First modification of the second embodiment>
FIG. 20 is a block diagram of the wireless receiver 40A according to the first modification of the second embodiment. The wireless reception device 40A further includes a reception quality determination unit 28 and a common key update unit 29 with respect to the wireless reception device 40. Since the operations of the reception quality determination unit 28 and the common key update unit 29 are the same as those of the wireless reception device 20A (FIG. 15), the description thereof will be omitted.

By considering the reception quality in the reception unit 22 in the reception quality determination unit 28, the fourth common key K24 is the common key (that is, the second common key) used in encrypting the error detection code in the wireless transmission device 30. It is possible to more accurately determine whether or not the key is different from the common key K22).

If it is determined that the common key used by the wireless receiving device 20 for decoding is incorrect, the common key updating unit 29 updates the common key held by the wireless receiving device 40 to obtain the received signal. The decryption process can be continued.

<Second variant of Embodiment 2>
FIG. 21 is a block diagram of the wireless transmission device 30B according to the second modification of the second embodiment. As shown in FIG. 21, the common key holding unit 11 includes a key expanding unit 111. The key extension unit 111 generates a first common key K21 and a second common key K22 from one common key by using a hash function such as SHA-2, a block cipher such as DES, or AES. ..

Since the wireless transmission device 30B in the second modification of the second embodiment includes the same configuration as the wireless transmission device 30 (FIG. 16), the same reference numerals are given to the same configurations. , Common description is omitted.

FIG. 22 is a block diagram of the wireless receiver 40B according to the second modification of the second embodiment. As shown in FIG. 22, the common key holding unit 21 includes a key expanding unit 211. The key extension unit 211 generates a third common key K23 and a fourth common key K24 from one common key by using a hash function such as SHA-2, a block cipher such as DES, or AES. ..

Since the wireless receiving device 40B in the second modification of the second embodiment includes the same configuration as the wireless receiving device 40A (FIG. 20), the same reference numerals are given to the same configurations. , Common description is omitted.

<Effect>
The wireless transmission device 30B in the second modification of the second embodiment further includes a key expansion unit 111 that generates each of the first common key K21 and the second common key K22 from one common key. Further, the wireless receiving device 40B in the second modification of the second embodiment further includes a key expansion unit 211 that generates each of the third common key K23 and the fourth common key K24 from one common key. ..

Therefore, in the wireless receiving device 40B, when the common key updating unit 29 updates the common key, only one common key needs to be updated, so that the data length to be updated can be reduced. Further, by generating the first and second common keys K21 and K22 from one common key, it is possible to enhance the confidentiality of the first and second common keys K21 and K22. Similarly, by generating the third and fourth common keys K23 and K24 from one common key, it is possible to enhance the confidentiality of the third and fourth common keys K23 and K24.

In the present invention, each embodiment can be freely combined, and each embodiment can be appropriately modified or omitted within the scope of the invention. Although the present invention has been described in detail, the above description is exemplary in all aspects and the invention is not limited thereto. It is understood that innumerable variations not illustrated can be assumed without departing from the scope of the present invention.

1A, 2B, 3C, 4D, 5E, 8B wireless device, 6A, 7B base station, 9A, 9B area, 10, 30, 30B wireless transmitter, 11,21 common key holder, 12 voice data acquisition unit, 13 voice Encryption unit, 14,25 error detection code calculation unit, 15,35 error detection code conversion unit, 16 transmitter unit, 20, 20A, 40, 40A, 40B wireless receiver, 22 receiver, 23 voice encryption / decryption unit, 24 , 44 Error detection code decoding unit, 26 Error detection code match determination unit, 27 Output unit, 28 Reception quality determination unit, 29 Common key update unit, 41,301 _, 302 Voice data, 111,211 Key expansion unit, 121 Mike, 122 A / D conversion unit, 123 audio compression unit, 131 selector, 151,241 exclusive OR calculation unit, 161 modulation unit, 162, 222 RF unit, 163,221 antenna, 223 demodulation unit, 271 audio restoration unit, 272 D / A converter, 273 speakers, 303,402 voice encryption data, 304,404,405 error detection code, 306,401 error detection code conversion data, 408 judgment result signal.

Claims (14)

A common key holding unit that holds the first common key and the second common key that is different from the first common key and is paired with the first common key.
The voice data acquisition unit that acquires voice data, and
A voice encryption unit that encrypts the voice data using the first common key to generate voice encrypted data, and a voice encryption unit.
An error detection code calculation unit that calculates an error detection code from the voice encrypted data,
An error detection code conversion unit that converts the error detection code using the second common key to generate error detection code conversion data, and an error detection code conversion unit.
A transmitter that wirelessly transmits data including the voice encrypted data and the error detection code conversion data, and
With
The second common key is the key number of the first common key.
The first common key is not directly generated from the second common key,
The error detection code conversion unit includes an exclusive OR operation unit.
The exclusive OR calculation unit calculates the exclusive OR of the error detection code and the key number of the first common key to obtain the error detection code conversion data.
Wireless transmitter. Each of the first common key and the second common key is a block cipher key having a block length of 64 bits or more.
The wireless transmission device according to claim 1. A key extension unit for generating each of the first common key and the second common key from one common key by using a hash function is further provided.
The wireless transmission device according to claim 2. A common key holding unit that holds a third common key and a fourth common key that is different from the third common key and is paired with the third common key.
A receiving unit that wirelessly receives data including voice encrypted data in which voice data is encrypted and error detection code conversion data in which an error detection code is converted from the voice encrypted data from a wireless transmission device.
A voice encryption / decryption unit that decrypts the voice data from the voice encryption data using the third common key, and a voice encryption / decryption unit.
An error detection code decoding unit that decodes the error detection code from the error detection code conversion data using the fourth common key, and an error detection code decoding unit.
An error detection code calculation unit that calculates an error detection code from the received voice-encrypted data,
With
The fourth common key is the key number of the third common key.
The third common key is not directly generated from the fourth common key,
The error detection code decoding unit includes an exclusive OR operation unit.
The exclusive OR calculation unit calculates the exclusive OR of the error detection code conversion data and the key number of the third common key, and decodes the error detection code.
Wireless receiver. An error detection code matching determination unit for determining whether or not the error detection code decoded from the error detection code conversion data and the error detection code calculated from the voice encryption data match is further provided.
In the error detection code matching determination unit, when the two error detection codes do not match, the fourth common key used when decoding the error detection code from the error detection code conversion data is the said. It is determined that the key is different from the common key used when converting the error detection code in the wireless transmitter.
The wireless receiver according to claim 4. Each of the third common key and the fourth common key is a block cipher key having a block length of 64 bits or more.
The wireless receiver according to claim 4 or 5. A key extension unit for generating each of the third common key and the fourth common key from one common key by using a hash function is further provided.
The wireless receiver according to claim 6. A reception quality determination unit that determines reception quality from the radio wave strength in the reception unit is further provided.
When it is determined that the reception quality in the receiving unit exceeds a predetermined standard and the error detection code matching determination unit determines that the two error detection codes do not match, the error detection code The match determination unit determines that the fourth common key is different from the common key used when converting the error detection code in the wireless transmission device.
The wireless receiver according to claim 5. The common key holding unit holds a plurality of combinations of the third common key and the fourth common key.
The error detection code decoding unit decodes a plurality of types of the error detection code from the error detection code conversion data by using each of the plurality of the fourth common keys.
The error detection code matching determination unit determines whether each of the plurality of error detection codes decoded from the error detection code conversion data matches the error detection code calculated from the voice encryption data.
The error detection code matching determination unit identifies the fourth common key used for decoding the error detection code that matches the error detection code calculated from the voice encryption data.
The voice encryption / decryption unit decrypts the voice data from the voice encryption data by using the third common key that is paired with the specified fourth common key.
The wireless receiver according to claim 5. With a common key update section
The fourth common key used by the error detection code matching determination unit when decoding the error detection code from the error detection code conversion data is used when converting the error detection code in the wireless transmission device. When it is determined that the common key is different from the common key, the common key update unit updates the third common key and the fourth common key.
The wireless receiver according to claim 5. The common key update unit requests the wireless transmitter to update the third common key and the fourth common key.
The wireless receiver according to claim 10. The common key update unit updates the third common key and the fourth common key based on the operation of the user.
The wireless receiver according to claim 10 or 11. A step of holding a first common key and a second common key that is different from the first common key and is paired with the first common key.
The process of acquiring voice data and
A step of encrypting the voice data using the first common key to generate voice encrypted data, and
The process of calculating the error detection code from the voice encrypted data and
A step of converting the error detection code using the second common key to generate error detection code conversion data, and
A step of wirelessly transmitting data including the voice encrypted data and the error detection code conversion data, and
With
The second common key is the key number of the first common key.
The first common key is not directly generated from the second common key,
The step of generating the error detection code conversion data is a step of calculating the exclusive OR of the error detection code and the key number of the first common key to generate the error detection code conversion data. ,
Wireless transmission method. A step of holding a third common key and a fourth common key that is different from the third common key and is paired with the third common key.
A process of wirelessly receiving data including voice encrypted data in which voice data is encrypted and error detection code conversion data in which an error detection code is converted from the voice encrypted data.
A step of decrypting the voice data from the voice encrypted data using the third common key, and
A step of decoding the error detection code from the error detection code conversion data using the fourth common key, and
The process of calculating the error detection code from the received voice encrypted data, and
With
The fourth common key is the key number of the third common key.
The third common key is not directly generated from the fourth common key,
The step of decoding the error detection code is a step of calculating the exclusive OR of the error detection code conversion data and the key number of the third common key to decode the error detection code.
Wireless reception method.

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