JP2021150706A - Radio communication device and radio communication system - Google Patents

Abstract

To improve confidentiality of data to be transmitted.SOLUTION: An encrypted call key transmitted via a company network line is decrypted using a cipher key transmitted via a private network line. Alternatively, a new call key is generated from the cipher key transmitted via the private network line and the call key transmitted via the company network line. Transmission data is encrypted using the decrypted call key or the new call key and the encrypted transmission data is transmitted via the company network line. Alternatively, encrypted reception data transmitted via the company network line is decrypted using the decrypted call key or the new call key.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to wireless communication devices and wireless communication systems.

Voice data transmitted by a wireless communication system may be eavesdropped by a third party. Therefore, in the wireless communication system, in order to conceal the contents of the transmitted voice data, the transmitted voice data is encrypted using an encryption key, and the transmitted encrypted voice data is an encryption key. Is decrypted using. The encryption key may be transmitted by the same line as the line that transmits voice data. The technique described in Patent Document 1 is an example.

Japanese Unexamined Patent Publication No. 11-234260

If the encryption key for encrypting the transmitted voice data and decrypting the transmitted encrypted voice data is transmitted by the same line as the line that transmits the voice data, the strength of the encryption is reduced. It has the same effect. This problem also occurs when data other than voice data is transmitted.

This disclosure has been made in view of this issue. An object of the present disclosure is to improve the confidentiality of transmitted data.

The present disclosure relates to a wireless communication device and a wireless communication system including the wireless communication device.

In the first aspect of the present disclosure, the wireless communication device includes a self-employed network communication unit, a business network communication unit, a call key decryption unit, and an encryption unit.

The self-employed network communication unit receives the encryption key transmitted via the self-employed network line.

The operator network communication unit receives the encrypted call key transmitted via the operator network line.

The call key decryption unit decrypts the call key encrypted using the encryption key and generates the decrypted call key.

The encryption unit encrypts the transmission data using the decrypted call key to generate the encrypted transmission data.

The business network communication department transmits encrypted transmission data via the business network line.

In the second aspect of the present disclosure, the wireless communication device includes a self-employed network communication unit, a business network communication unit, a call key decryption unit, and a encryption / decryption unit.

The self-employed network communication unit receives the encryption key transmitted via the self-employed network line.

The operator network communication unit receives the encrypted call key and the encrypted received data transmitted via the operator network line.

The call key decryption unit decrypts the call key encrypted using the encryption key and generates the decrypted call key.

The encryption / decryption unit decrypts the encrypted received data using the decrypted call key and generates the decrypted received data.

In the third aspect of the present disclosure, the wireless communication device includes a self-employed network communication unit, a business network communication unit, a call key calculation unit, and an encryption unit.

The self-employed network communication unit receives the encryption key transmitted via the self-employed network line.

The business network communication department receives the call key transmitted via the business network line.

The call key calculation unit calculates a new call key from the encryption key and the call key.

The encryption unit encrypts the transmission data using the new call key to generate the encrypted transmission data.

The business network communication department transmits encrypted transmission data via the business network line.

In the fourth aspect of the present disclosure, the wireless communication device includes a self-employed network communication unit, a business network communication unit, a call key calculation unit, and a encryption / decryption unit.

The self-employed network communication unit receives the encryption key transmitted via the self-employed network line.

The operator network communication unit receives the call key and the encrypted reception data transmitted via the operator network line.

The call key calculation unit calculates a new call key from the encryption key and the call key.

The encryption / decryption unit decrypts the encrypted received data using the new call key and generates the decrypted received data.

According to the present disclosure, an encryption key transmitted by a self-employed network line having high confidentiality is used for encrypting the transmitted data or decrypting the transmitted encrypted data. Therefore, the confidentiality of the transmitted data can be improved.

The purposes, features, aspects and advantages of the present disclosure will be made clearer by the following detailed description and accompanying drawings.

It is a block diagram which schematically illustrates the wireless communication system of Embodiment 1-2. It is a block diagram which shows typically the encryption key management part provided in the wireless communication system of Embodiment 1. FIG. It is a block diagram which shows typically each wireless terminal provided in the wireless communication system of Embodiment 1. FIG. FIG. 5 is a block diagram schematically illustrating a call key encryption unit provided in the wireless communication system of the first embodiment. It is a block diagram which schematically illustrates the call key decoding unit provided in the wireless communication system of Embodiment 1. It is a block diagram which shows typically the encryption key management part provided in the wireless communication system of Embodiment 2. It is a block diagram which shows typically each wireless terminal provided in the wireless communication system of Embodiment 2. It is a block diagram which shows typically the call key calculation part provided in the wireless communication system of Embodiment 2. It is a figure schematically explaining the generation of the new call key in the wireless communication system of Embodiment 2.

1 Embodiment 1
1.1 Wireless Communication System FIG. 1 is a block diagram schematically showing the wireless communication system of the first embodiment.

The wireless communication system 1 illustrated in FIG. 1 is a digital wireless communication system for performing voice communication.

As shown in FIG. 1, the wireless communication system 1 includes an encryption key management unit 101, a call distribution unit 102, a self-employed network base station 103, a business network base station 104, a first wireless terminal 105a, and a second radio. A terminal 105b is provided.

The encryption key management unit 101 and the self-employed network base station 103 are connected to each other so as to be able to communicate with each other via the self-employed network line 111. The encryption key management unit 101 and the business network base station 104 are connected to each other so as to be able to communicate with each other via the business network line 112. The call distribution unit 102 and the operator network base station 104 are connected to each other so as to be able to communicate with each other via the operator network line 112.

The self-employed network base station 103 and each of the wireless terminals 105 of the first wireless terminal 105a and the second wireless terminal 105b are communicably connected to each other via the first wireless line 121. The operator network base station 104 and each wireless terminal 105 are communicably connected to each other via a second wireless line 122.

As a result, the encryption key management unit 101 and each wireless terminal 105 are communicably connected to each other via the self-employed network line 111, the self-employed network base station 103, and the first wireless line 121. The encryption key management unit 101 and each wireless terminal 105 are further connected to each other so as to be able to communicate with each other via the operator network line 112, the operator network base station 104, and the second wireless line 122. The call distribution unit 102 and each wireless terminal 105 are communicably connected to each other via the operator network line 112, the operator network base station 104, and the second wireless line 122.

The self-employed network line 111 and the first wireless line 121 have high confidentiality, but can transmit data only at a low speed. The operator network line 112 and the second wireless line 122 have low confidentiality, but can transmit data at high speed. The operator network line 112 includes the Internet network 131.

The encryption key management unit 101 generates an encryption key and an encrypted call key. In addition, the encryption key management unit 101 manages the encryption key and the encrypted call key. Further, the encryption key management unit 101 transmits an encryption key to each wireless terminal 105 via the self-employed network line 111, the self-employed network base station 103, and the first wireless line 121. Further, the encryption key management unit 101 transmits an encrypted call key to each wireless terminal 105 via the operator network line 112, the operator network base station 104, and the second wireless line 122. The encryption key management unit 101 is configured by causing a computer to execute a program. All or part of the encryption key management unit 101 may be configured by hardware.

The call distribution unit 102 receives encrypted voice data and control data from each wireless terminal 105 via the second wireless line 122, the operator network base station 104, and the operator network line 112. In addition, the call distribution unit 102 transmits encrypted voice data and control data to each wireless terminal 105 via the operator network line 112, the operator network base station 104, and the second wireless line 122. The call distribution unit 102 is configured by causing a computer to execute a program. All or part of the call distribution unit 102 may be configured by hardware.

Each wireless terminal 105 is a wireless terminal for performing voice communication. Each wireless terminal 105 receives an encryption key from the encryption key management unit 101 via the self-employed network line 111, the self-employed network base station 103, and the first wireless line 121. Further, each wireless terminal 105 receives an encrypted call key from the encryption key management unit 101 via the operator network line 112, the operator network base station 104, and the second wireless line 122. In addition, each wireless terminal 105 decrypts the encrypted call key using the encryption key to generate the decrypted call key. In addition, each wireless terminal 105 transmits encrypted voice data and control data to the call distribution unit 102 via the second wireless line 122, the operator network base station 104, and the operator network line 112. In addition, each wireless terminal 105 receives encrypted voice data and control data from the call distribution unit 102 via the operator network line 112, the operator network base station 104, and the second wireless line 122.

When voice communication is performed between the first wireless terminal 105a and the second wireless terminal 105b, the first wireless terminal 105a converts the voice into voice data. In addition, the first wireless terminal 105a encrypts the voice data using the decrypted call key to generate the encrypted voice data. In addition, the first wireless terminal 105a transmits the encrypted voice data. The encrypted voice data is transmitted by the second wireless line 122, the operator network base station 104, and the operator network line 112. The call distribution unit 102 receives the transmitted encrypted voice data. In addition, the call distribution unit 102 transmits the encrypted voice data. The encrypted voice data is transmitted by the operator network line 112, the operator network base station 104, and the second radio line 122. The second wireless terminal 105b receives the transmitted encrypted voice data. In addition, the second wireless terminal 105b decodes the encrypted voice data using the decrypted call key to generate the decrypted voice data.

1.2 Encryption Key Management Unit FIG. 2 is a block diagram schematically illustrating an encryption key management unit provided in the wireless communication system of the first embodiment.

As shown in FIG. 2, the encryption key management unit 101 includes an encryption key generation unit 201, a call key generation unit 202, a call key encryption unit 203, an encryption key distribution unit 204, and a call key distribution unit 205.

The encryption key generation unit 201 generates the encryption key K1. The encryption key K1 is a random number, for example, a short encryption key having a key length of 128 bits. Further, the encryption key generation unit 201 outputs the encryption key K1 to the call key encryption unit 203 and the encryption key distribution unit 204.

The call key generation unit 202 generates the call key K2. The call key K2 is a random number, for example, a long call key having a key length of 12800 bits. Further, the call key generation unit 202 outputs the call key K2 to the call key encryption unit 203.

The call key encryption unit 203 encrypts the call key K2 using the encryption key K1 to generate the encrypted call key K3. Further, the call key encryption unit 203 outputs the encrypted call key K3 to the call key distribution unit 205.

The encryption key distribution unit 204 transmits the encryption key K1 to the self-employed network base station 103 via the self-employed network line 111.

The call key distribution unit 205 transmits the encrypted call key K3 to the operator network base station 104 via the operator network line 112.

1.3 Wireless Terminals FIG. 3 is a block diagram schematically illustrating each wireless terminal provided in the wireless communication system of the first embodiment.

Each wireless terminal 105 illustrated in FIG. 3 is a wireless communication device.

As shown in FIG. 3, each wireless terminal 105 includes a self-employed network communication unit 301, a business network communication unit 302, a call key decryption unit 303, a microphone 304, an analog / digital (A / D) conversion unit 305, and a voice. It includes a compression unit 306, a voice encryption unit 307, a voice encryption / decryption unit 308, a voice decoding unit 309, a digital / analog (D / A) conversion unit 310, and a speaker 311.

The call key decryption unit 303, the voice compression unit 306, the voice encryption unit 307, the voice encryption / decryption unit 308, and the voice decryption unit 309 are configured by causing a computer to execute a program. All or part of the call key decryption unit 303, the voice compression unit 306, the voice encryption unit 307, the voice encryption / decryption unit 308, and the voice decryption unit 309 may be configured by hardware.

First, a configuration for generating a decrypted call key K4 by each wireless terminal 105 will be described.

The self-employed network communication unit 301 receives a radio signal from the self-employed network base station 103 via the first wireless line 121. In addition, the self-employed network communication unit 301 wirelessly converts the wireless signal. In addition, the self-employed network communication unit 301 demodulates the wirelessly converted radio signal. As a result, the self-employed network communication unit 301 receives the encryption key K1 transmitted via the self-employed network line 111. The self-employed network communication unit 301 outputs the encryption key K1 to the call key decryption unit 303.

The operator network communication unit 302 receives a radio signal from the operator network base station 104 via the second radio line 122. In addition, the operator network communication unit 302 wirelessly converts the wireless signal. In addition, the operator network communication unit 302 demodulates the wirelessly converted wireless signal. As a result, the operator network communication unit 302 receives the encrypted call key K3 transmitted via the operator network line 112. The operator network communication unit 302 outputs the encrypted call key K3 to the call key decryption unit 303.

The call key decryption unit 303 decrypts the above-mentioned encrypted call key K3 using the above-mentioned encryption key K1 to generate the decrypted call key K4. Further, the call key decryption unit 303 outputs the decrypted call key K4 to the voice encryption unit 307 and the voice encryption / decryption unit 308.

Subsequently, a configuration for each wireless terminal 105 to transmit voice data will be described.

The microphone 304 converts the voice emitted by the speaker into a voice signal. The microphone 304 outputs an audio signal to the A / D conversion unit 305.

The A / D conversion unit 305 converts an audio signal, which is an analog signal, into audio data, which is a digital signal. The A / D conversion unit 305 outputs audio data to the audio compression unit 306.

The audio compression unit 306 compresses the audio data to generate transmission data. At that time, the voice compression unit 306 compresses the voice data by voice coding, for example, every 20 milliseconds. Further, the voice compression unit 306 outputs the transmission data to the voice encryption unit 307. The transmitted data is voice data.

The voice encryption unit 307 encrypts the transmission data using the decrypted call key K4 to generate the encrypted transmission data. The voice encryption unit 307 outputs the encrypted transmission data to the business network communication unit 302. The encrypted transmission data is voice data.

The operator network communication unit 302 modulates the carrier wave with the encrypted transmission data to generate a radio signal. In addition, the operator network communication unit 302 wirelessly converts the wireless signal. Further, the operator network communication unit 302 transmits a wirelessly converted wireless signal to the operator network base station 104 via the second wireless line 122. As a result, the business network communication unit 302 transmits the encrypted transmission data via the business network line 112.

Subsequently, a configuration for each wireless terminal 105 to receive voice data will be described.

The operator network communication unit 302 receives a radio signal from the operator network base station 104 via the second wireless line 122. In addition, the operator network communication unit 302 wirelessly converts the wireless signal. In addition, the operator network communication unit 302 demodulates the wirelessly converted wireless signal. As a result, the business network communication unit 302 receives the encrypted reception data transmitted via the business network line 112. The operator network communication unit 302 outputs the encrypted received data to the voice encryption / decryption unit 308. The encrypted received data is voice data.

The voice encryption / decryption unit 308 decrypts the above-mentioned encrypted reception data using the above-mentioned decrypted call key K4 to generate the decrypted reception data. Further, the voice encryption / decryption unit 308 outputs the decrypted received data to the voice decoding / decoding unit 309. The decoded received data is voice data.

The voice decoding unit 309 voice-decodes the decoded received data to obtain voice data. At that time, the voice decoding unit 309 voice-decodes the received data decoded every 20 milliseconds, for example. Further, the voice decoding unit 309 outputs the voice data to the D / A conversion unit 310.

The D / A conversion unit 310 converts audio data, which is a digital signal, into an audio signal, which is an analog signal. The D / A conversion unit 310 outputs an audio signal to the speaker 311.

The speaker 311 converts the voice signal into voice.

1.4 Call Key Encryption Unit FIG. 4 is a block diagram schematically illustrating a call key encryption unit provided in the wireless communication system of the first embodiment.

The call key encryption unit 203 includes an encryption unit 401 as shown in FIG.

When the call key K2 is updated, the encryption unit 401 encrypts the call key K2 using the encryption key K1 to generate the encrypted call key K3. Further, the encryption unit 401 outputs the encrypted call key K3 to the call key distribution unit 205. Encryption is performed by a common key encryption method such as DES (Data Encryption Standard), AES (Advanced Encryption Standard), or Camellia.

1.5 Call key decryption unit, voice encryption unit, and voice encryption / decryption unit FIG. 5 is a block diagram schematically showing a call key decryption unit provided in the wireless communication system of the first embodiment.

As shown in FIG. 5, the call key decoding unit 303 includes a decoding unit 501, a call key storage unit 502, and a division unit 503.

When the call key K2 is updated and the encrypted call key K3 is updated, the decryption unit 501 decrypts and decrypts the above-mentioned encrypted call key K3 using the above-mentioned encryption key K1. Generate key K4. Decryption is performed by a cryptographic algorithm of a common key cryptosystem such as DES, AES, or Camellia. The decoding unit 501 stores the decrypted call key K4 in the call key storage unit 502.

When a voice call is made, the division unit 503 reads out the decrypted call key K4 stored in the call key storage unit 502. Further, the division unit 503 divides the decrypted call key K4 into a plurality of call keys K5. The division unit 503 divides the decrypted call key K4 into, for example, 128 bits. The division unit 503 outputs a plurality of call keys K5 to the voice encryption unit 307 and the voice encryption / decryption unit 308.

The voice encryption unit 307 encrypts the transmission data using the call keys included in the plurality of call keys K5. When the decrypted call key K4 is divided into 128-bit units, the voice encryption unit 307 encrypts the transmission data using one call key having a key length of 128 bits. The voice encryption unit 307 changes the call key used in the set cycle. The set period is, for example, 20 milliseconds. When the decrypted call key K4 has a key length of 12800 bits and is divided into 100, and the set cycle is 20 milliseconds, the voice encryption unit 307 uses 20 call keys for encrypting the transmitted data. It is changed every millisecond, and every time the decrypted call key K4 is generated, the call key for encrypting the transmission data is changed 100 times.

The voice encryption / decryption unit 308 decrypts the received data encrypted by using the call keys included in the plurality of call keys K5. When the decrypted call key K4 is divided into 128-bit units, the voice encryption / decryption unit 308 decrypts the encrypted received data using one call key having a key length of 128 bits. The voice encryption / decryption unit 308 changes the call key used in the set cycle. The set period is, for example, 20 milliseconds. When the decrypted call key K4 has a key length of 12800 bits and is divided into 100 and the set cycle is 20 milliseconds, the voice encryption / decryption unit 308 makes a call for decrypting the encrypted received data. The key is changed every 20 milliseconds, and every time the decrypted call key K4 is generated, the call key for decrypting the encrypted received data is changed 100 times.

As a result, in each wireless terminal 105, the encrypted call key K3 is decrypted using the encryption key K1 transmitted by the self-employed network line 111 having high confidentiality. Further, the transmitted data is encrypted using the decrypted call key K4, and the encrypted received data is decrypted. Therefore, the high confidentiality of the self-employed network line 111 ensures the confidentiality of the transmitted data and the received data. Therefore, according to the first embodiment, the confidentiality of the transmitted data and the received data to be transmitted can be improved.

Further, in each wireless terminal 105, the long decrypted call key K4 is divided, and the call key for encrypting the transmission data and the call key for decrypting the encrypted received data are set at a set cycle. Be changed. Thereby, the confidentiality of the transmitted data and the received data to be transmitted can be further improved. Since the long decrypted call key K4 is transmitted by the operator network line 112 capable of transmitting data at high speed, a long decrypted call key K4 does not bring about a significant increase in transmission time.

1.6 Modification Example In the first embodiment, each wireless terminal 105 has a transmission function for transmitting encrypted transmission data and a reception function for receiving encrypted reception data. However, each wireless terminal 105 may have only one of a transmission function and a reception function.

Further, in the first embodiment, the wireless communication system 1 is a wireless communication system for performing voice communication. Therefore, the transmitted data is voice data. However, the wireless communication system 1 may be a wireless communication system for performing communication other than voice communication. Therefore, the data to be transmitted may be data other than voice data. When the data to be transmitted is data other than voice data, the voice encryption unit 307, which is an encryption unit that encrypts the voice data, is replaced with an encryption unit that encrypts the data other than the voice data. Further, the voice encryption / decryption unit 308, which is an encryption / decryption unit that decrypts the encrypted voice data, is replaced with the encryption / decryption unit that decrypts the encrypted data other than the voice data.

2 Embodiment 2
2.1 Wireless communication system FIG. 1 is also a block diagram schematically illustrating the wireless communication system of the second embodiment.

The wireless communication system 2 of the second embodiment illustrated in FIG. 1 differs from the wireless communication system 1 of the first embodiment mainly in the following points. Regarding points not described below, the same configuration as that adopted in the wireless communication system 1 of the first embodiment is also adopted in the wireless communication system 2 of the second embodiment.

2.2 Encryption key management unit FIG. 6 is a block diagram schematically showing an encryption key management unit provided in the wireless communication system of the second embodiment.

As shown in FIG. 6, the encryption key management unit 101 includes an encryption key generation unit 201, a call key generation unit 202, a fixed key storage unit 601, a call key encryption unit 203, an encryption key delivery unit 204, and a call key delivery unit. A unit 205 is provided.

The encryption key generation unit 201, the call key generation unit 202, the call key encryption unit 203, the encryption key distribution unit 204, and the call key distribution unit 205 provided in the wireless communication system 2 of the second embodiment are the radios of the first embodiment. It corresponds to the encryption key generation unit 201, the call key generation unit 202, the call key encryption unit 203, the encryption key distribution unit 204, and the call key distribution unit 205 provided in the communication system 1, respectively.

The encryption key generation unit 201 outputs the encryption key K1 to the encryption key distribution unit 204.

The fixed key storage unit 601 stores the fixed key K6. The fixed key K6 is a random number, for example, a short fixed key having a key length of 128 bits. The fixed key K6 is fixed. The fixed key storage unit 601 outputs the fixed key K6 to the call key encryption unit 203.

The call key encryption unit 203 encrypts the call key K2 using the fixed key K6 to generate the encrypted call key K3.

2.3 Wireless Terminals FIG. 7 is a block diagram schematically illustrating each wireless terminal provided in the wireless communication system of the second embodiment.

As shown in FIG. 7, each wireless terminal 105 has a self-employed network communication unit 301, a business network communication unit 302, a call key calculation unit 701, a fixed key storage unit 702, a microphone 304, and an A / D conversion unit 305. It includes a voice compression unit 306, a voice encryption unit 307, a voice encryption / decryption unit 308, a voice decoding unit 309, a D / A conversion unit 310, and a speaker 311.

Self-employed network communication unit 301, operator network communication unit 302, microphone 304, A / D conversion unit 305, voice compression unit 306, voice encryption unit 307, voice encryption / decryption unit provided in the wireless communication system 2 of the second embodiment. The 308, the voice decoding unit 309, the D / A conversion unit 310, and the speaker 311 are the self-employed network communication unit 301, the operator network communication unit 302, the microphone 304, and the A / D conversion provided in the wireless communication system 1 of the first embodiment. It corresponds to the unit 305, the voice compression unit 306, the voice encryption unit 307, the voice encryption / decryption unit 308, the voice decryption unit 309, the D / A conversion unit 310, and the speaker 311 respectively.

The fixed key storage unit 702 stores the fixed key K6 in the same manner as the fixed key storage unit 601. The fixed key K6 is a random number, for example, a short fixed key having a key length of 128 bits. The fixed key K6 is fixed. The fixed key storage unit 702 outputs the fixed key K6 to the call key calculation unit 701.

The operator network communication unit 302 receives the call key K3.

The call key calculation unit 701 calculates a new call key K7 from the encryption key K1 and the call key K3. The call key K3 is an encrypted call key. The call key calculation unit 701 decrypts the above-mentioned encrypted call key K3 using the above-mentioned fixed key K6 to generate the decrypted call key. Further, the call key calculation unit 701 calculates a new call key K7 from the encryption key K1 and the decrypted call key. Further, the call key calculation unit 701 outputs a new call key K7 to the voice encryption unit 307 and the voice encryption / decryption unit 308.

The voice encryption unit 307 encrypts the transmission data using the new call key K7 to generate the encrypted transmission data.

The voice encryption / decryption unit 308 decrypts the encrypted reception data using the new call key K7 and generates the decrypted reception data.

2.4 Call key decryption unit FIG. 8 is a block diagram schematically showing a call key calculation unit provided in the wireless communication system of the second embodiment.

As shown in FIG. 8, the call key calculation unit 701 includes a decoding unit 501, a call key storage unit 502, a key derivation unit 801 and a key binding unit 802.

When the call key K2 is updated and the encrypted call key K3 is updated, the decryption unit 501 decrypts and decrypts the above-mentioned encrypted call key K3 using the above-mentioned fixed key K6. Generate key K8. The decoding unit 501 stores the decrypted call key K8 in the call key storage unit 502.

The key derivation unit 801 derives the derivation key K9 from the encryption key K1 by using a key derivation function (KDF). The derived key K9 has, for example, a key length of 12800 bits. Further, the key derivation unit 801 outputs the derivation key K9 to the key combination unit 805.

When a voice call is made, the key binding unit 802 reads out the decrypted call key K8 stored in the call key storage unit 502. Further, the key binding unit 802 combines the decrypted call key K8 and the derived key K9 to generate a new call key K7. Further, the key binding unit 802 outputs a new call key K7 to the voice encryption unit 307 and the voice encryption / decryption unit 308.

2.5 Combining a Call Key and a Derivation Key FIG. 9 is a diagram schematically illustrating the generation of a new call key in the wireless communication system of the second embodiment.

When the decrypted call key K8 and the derived key K9 are combined, the key binding unit 802 combines the decrypted call keys K8 with the plurality of call keys K8a, K8b, K8c, K8d and as shown in FIG. Divide into K8e. At that time, the key binding unit 802 divides, for example, the decrypted call key K8 into 128-bit units.

Further, when the key binding unit 802 combines the decrypted call key K8 and the derived key K9, the derived key K9 is combined with the plurality of derived keys K9a, K9b, K9c, K9d and K9e as shown in FIG. Divide into. At that time, the key binding unit 802 divides the derived key K9 into, for example, 128 bits.

Further, as shown in FIG. 9, the key binding unit 802 is an exclusive OR of the plurality of call keys K8a, K8b, K8c, K8d and K8e and the plurality of derived keys K9a, K9b, K9c, K9d and K9e. The calculation is performed to generate a plurality of call keys K7a, K7b, K7c, K7d and K7e, respectively. The plurality of call keys K7a, K7b, K7c, K7d and K7e constitute a new call key K7. Further, the key binding unit 802 outputs a plurality of call keys K7a, K7b, K7c, K7d and K7e to the voice encryption unit 307 and the voice encryption / decryption unit 308. The plurality of call keys K7a, K7b, K7c, K7d and K7e are sequentially output, for example, every 20 milliseconds.

The voice encryption unit 307 encrypts the transmission data using the call keys included in the plurality of call keys K7a, K7b, K7c, K7d and K7e. Each of the plurality of call keys K7a, K7b, K7c, K7d and K7e has a key length of, for example, 128 bits. The voice encryption unit 307 changes the call key used in the set cycle. The set period is, for example, 20 milliseconds. When the set cycle is 20 milliseconds, the voice encryption unit 307 changes the call key for encrypting the transmission data every 20 milliseconds.

The voice encryption / decryption unit 308 decrypts the received data encrypted by using the call keys included in the plurality of call keys K7a, K7b, K7c, K7d and K7e. Each of the plurality of call keys K7a, K7b, K7c, K7d and K7e has a key length of, for example, 128 bits. The voice encryption / decryption unit 308 changes the call key used in the set cycle. The set period is, for example, 20 milliseconds. When the set cycle is 20 milliseconds, the voice encryption / decryption unit 308 changes the call key for decrypting the encrypted received data every 20 milliseconds.

As a result, in each wireless terminal 105, a new call key K7 is generated from the encryption key K1 transmitted by the self-employed network line 111 having high confidentiality. Further, the transmitted data is encrypted and the encrypted received data is decrypted by using the new call key K7. Therefore, the high confidentiality of the self-employed network line 111 ensures the confidentiality of the transmitted data and the received data. Therefore, according to the second embodiment, the confidentiality of the transmitted data and the received data to be transmitted can be improved.

Further, in each wireless terminal 105, a plurality of call keys K7a, K7b, K7c, K7d and K7e are generated, and a call key for encrypting the transmission data and a call key for decrypting the encrypted reception data. Is changed at the set cycle. Thereby, the confidentiality of the transmitted data and the received data to be transmitted can be further improved.

In addition, each embodiment can be freely combined, and each embodiment can be appropriately modified or omitted.

Although the present disclosure has been described in detail, the above description is exemplary and not limiting in all respects. A myriad of variants not illustrated are understood to be conceivable.

1, 2, wireless communication system, 101 encryption key management unit, 102 call distribution unit, 105 wireless terminal, 111 self-employed network line, 112 operator network line, 201 encryption key generation unit, 202 call key generation unit, 203 call key encryption Department, 204 Encryption Key Delivery Department, 205 Call Key Delivery Department, 301 Self-employed Network Communication Department, 302 Business Network Communication Department, 303 Call Key Decryption Department, 306 Voice Compression Department, 307 Voice Encryption Department, 308 Voice Encryption Decryption Department, 309 voice decryption unit, 701 call key calculation unit, 702 fixed key storage unit.

Claims (18)

The self-employed network communication department that receives the encryption key transmitted via the self-employed network line,
The operator network communication department that receives the encrypted call key transmitted via the operator network line,
A call key decryption unit that decrypts the encrypted call key using the encryption key and generates a decrypted call key, and a call key decryption unit.
An encryption unit that encrypts transmission data using the decrypted call key to generate encrypted transmission data, and
With
The operator network communication unit is a wireless communication device that transmits the encrypted transmission data via the operator network line. The call key decryption unit divides the decrypted call key into a plurality of call keys, and divides the decrypted call key into a plurality of call keys.
The wireless communication device according to claim 1, wherein the encryption unit encrypts the transmission data using the call keys included in the plurality of call keys, and changes the call key used in a set cycle. The wireless communication device according to claim 1 or 2, wherein the transmission data and the encrypted transmission data are voice data. The self-employed network communication department that receives the encryption key transmitted via the self-employed network line,
The operator network communication department that receives the encrypted call key and encrypted received data transmitted via the operator network line,
A call key decryption unit that decrypts the encrypted call key using the encryption key and generates a decrypted call key, and a call key decryption unit.
An encryption / decryption unit that decrypts the encrypted received data using the decrypted call key and generates the decrypted received data.
A wireless communication device equipped with. The call key decryption unit divides the decrypted call key into a plurality of call keys, and divides the decrypted call key into a plurality of call keys.
The wireless communication device according to claim 4, wherein the encryption / decryption unit decrypts the encrypted received data using the call keys included in the plurality of call keys, and changes the call key used in a set cycle. The wireless communication device according to claim 4 or 5, wherein the encrypted received data and the decrypted received data are voice data. It is provided with an encryption unit that encrypts transmission data using the decrypted call key and generates encrypted transmission data.
The wireless communication device according to any one of claims 4 to 6, wherein the business network communication unit transmits the encrypted transmission data via the business network line. The self-employed network communication department that receives the encryption key transmitted via the self-employed network line,
The business network communication department that receives the call key sent via the business network line,
A call key calculation unit that calculates a new call key from the encryption key and the call key,
An encryption unit that encrypts transmission data using the new call key to generate encrypted transmission data, and
With
The operator network communication unit is a wireless communication device that transmits the encrypted transmission data via the operator network line. The new call key is composed of a plurality of call keys.
The wireless communication device according to claim 8, wherein the encryption unit encrypts the transmission data using the call keys included in the plurality of call keys, and changes the call key used in a set cycle. The wireless communication device according to claim 8 or 9, wherein the transmission data and the encrypted transmission data are voice data. The self-employed network communication department that receives the encryption key transmitted via the self-employed network line,
The business network communication department that receives the call key and encrypted received data transmitted via the business network line,
A call key calculation unit that calculates a new call key from the encryption key and the call key,
An encryption / decryption unit that decrypts the encrypted received data using the new call key and generates the decrypted received data.
A wireless communication device equipped with. The new call key is composed of a plurality of call keys.
The wireless communication device according to claim 11, wherein the encryption / decryption unit decrypts the encrypted received data by using the call keys included in the plurality of call keys, and changes the call key used in a set cycle. The wireless communication device according to claim 11 or 12, wherein the received data and the encrypted received data are voice data. It is provided with an encryption unit that encrypts transmission data using the new call key and generates encrypted transmission data.
The wireless communication device according to any one of claims 11 to 13, wherein the business network communication unit transmits the encrypted transmission data via the business network line. Equipped with a fixed key storage unit that stores fixed keys
The call key is an encrypted call key, and the call key is an encrypted call key.
The call key calculation unit decrypts the encrypted call key using the fixed key to generate a decrypted call key, and obtains the new call key from the encryption key and the decrypted call key. The wireless communication device according to any one of claims 8 to 14 to be calculated. The radio of claim 15 that the call key calculation unit derives a derivation key from the encryption key using a key derivation function, and combines the decrypted call key and the derivation key to generate the new call key. Communication device. With any of the wireless communication devices of claims 1 to 7,
An encryption key management unit that transmits the encryption key to the wireless communication device via the self-employed network line and transmits the encrypted call key to the wireless communication device via the business operator network line.
A wireless communication system including. With any of the wireless communication devices of claims 8 to 16.
An encryption key management unit that transmits the encryption key to the wireless communication device via the self-employed network line and transmits the call key to the wireless communication device via the business operator network line.
A wireless communication system including.

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