JP2010239352A - Network terminal and communication method - Google Patents

Abstract

There is provided a network terminal and a communication method capable of safely passing a key to a partner network terminal by a simple operation with a very low possibility of leakage of an encryption key.
A communication method of a network terminal 1a that communicates with a counterpart network terminal 1b, wherein at least one of keys for encryption and decryption managed by the network terminal 1a is assigned to the network terminal 1b. The first data is encrypted using a key managed by the network terminal 1a so that it can be decrypted using the key transmitted by infrared, and And transmitting the first data to the counterpart network terminal 1b via the network (S105).
[Selection] Figure 2

Description

  The present invention relates to a network terminal that communicates with another network terminal via a network, and a communication method therefor.

  In recent years, an increasing number of wireless network terminals have a function of connecting to a wireless network such as a wireless LAN. In addition, the use of a wireless network for a home network or the like to exchange data such as contents between devices is expected to increase in the future. Unlike a wired network, a wireless network is relatively easy for a third party to intercept due to its characteristics. For this reason, when plaintext data is transmitted / received via a wireless network, there is a possibility that the contents of communication may be leaked to a third party. In order to prevent this, it is common in wireless networks to encrypt data for communication.

  In encrypted communication, a receiving terminal needs to know a key for decrypting data transmitted by a transmitting terminal. Using a common key method that uses the same key as an encryption method and a decryption key as an encryption method, and a different key as an encryption key and a decryption key, A public key method in which a key for encryption is made public, the terminal on the transmission side encrypts and transmits the data with the key, and the data encrypted with the key secreted by the terminal on the reception side is decrypted There is. Regardless of which method is used, it is necessary to exchange keys because the keys used for encrypted communication must be known to each other. However, in the case of a wireless LAN, since it is relatively easy for a third party to intercept, if the encryption key is exchanged directly by wireless communication, there is a risk that the key leaks. In order to reduce such a risk, there is a method of exchanging an encryption key after narrowing a range in which radio waves reach by performing an operation of reducing a wireless transmission output (see, for example, Patent Document 1). Further, there is a method for exchanging authentication data between a terminal and a base station using an authentication card having a storage unit as a medium (see, for example, Patent Document 2).

JP 2004-215232 A (page 7-11, FIG. 3) JP 2001-189722 A (page 6-10, FIG. 1)

  However, in the method described in Patent Document 1, the wireless transmission output is lowered, but the encryption key is transmitted wirelessly, and the encryption key itself is not encrypted and is in plain text. Since the data is transmitted, there is a problem that the encryption key may be leaked by intercepting the key data by a third party. Further, in the method described in Patent Document 1, encryption is performed on a terminal that first sends subscription instruction data to an access point from the time of performing an operation of lowering a wireless transmission output (an operation of pressing a registration button). Since the key is sent, there is a problem that the encryption key may be sent to a terminal different from the terminal intended for connection.

  Further, in the method described in Patent Document 2, an operation for inserting the authentication card into the authentication card writing unit of the wireless terminal, an operation of inserting the authentication card into the reading unit of the wireless base station, and the like are required, which takes time. There was a problem. In addition, when the user removes the authentication card from the device and carries it, the authentication card may be lost.

  Therefore, the present invention has been made to solve the above-described problems of the prior art, and the purpose of the present invention is to reduce the risk of leakage of a key for encryption and decryption, and to secure the key safely with a simple operation. Is to provide a network terminal and a communication method.

  A network terminal according to the present invention is a network terminal that communicates with a counterpart network terminal, and manages key for encryption and decryption, and at least of keys managed by the key management means Infrared transmitting means for transmitting one key to the counterpart network terminal by infrared, and first data can be decrypted using the key transmitted by the infrared using the key managed by the key managing means. And a data encryption means for encrypting and a network transmission means for transmitting the encrypted first data to the counterpart network terminal via a network.

  Further, another network terminal according to the present invention is a network terminal that communicates with a counterpart network terminal, and at least one key of encryption and decryption keys managed by the counterpart network terminal is obtained, Using infrared receiving means that receives infrared rays from the counterpart network terminal and a key managed by the counterpart network terminal, the first data that is encrypted and transmitted using the key received by the infrared rays is decrypted, It comprises network receiving means for receiving from the other party network terminal via a network, and data decrypting means for decrypting the received first data using the key received by the infrared ray. .

  Furthermore, another network terminal according to the present invention is a network terminal that communicates with a counterpart network terminal, and that manages key for encryption and decryption, and a key managed by the key management means. Infrared transmitting means for transmitting the first key included in the key to the counterpart network terminal by infrared and a key managed by the key managing means for the second key included in the key managed by the key managing means The first data can be decrypted using the second key, and the first data can be decrypted using the key managed by the key management means. Data encryption means for performing encryption processing, processing for transmitting the encrypted second key to the counterpart network terminal via the network, and the encrypted first data for the network Sutra In is characterized by having a network transmission unit that performs a process of transmitting to the counterpart network terminal.

  Furthermore, another network terminal according to the present invention is a network terminal that communicates with a counterpart network terminal, and includes a first key included in a key for encryption and decryption managed by the counterpart network terminal. Using the infrared receiving means for receiving from the other party network terminal by infrared and the key managed by the other party network terminal, the second key encrypted so as to be decryptable by using the first key, Using the process received from the network terminal via the network and the key managed by the counterpart network terminal, the first data transmitted after being encrypted and transmitted using the second key is decrypted. A network receiving means for performing processing for receiving from a terminal via a network, and the encrypted second key; Data decrypting means for performing processing for decrypting using the first key received in step 1 and processing for decrypting the received first data using the decrypted second key It is characterized by having.

  According to the present invention, since the exchange of keys for encryption and decryption between network terminals is performed by infrared rays, the risk of key leakage is low and the keys can be exchanged safely with simple operation. There is an effect that can be.

It is a block diagram which shows roughly the structure of the network terminal which concerns on Embodiment 1 of this invention. It is a sequence diagram which shows operation | movement (namely, communication method which concerns on Embodiment 1) of the network terminal which concerns on Embodiment 1 of this invention. 5 is an example of a screen used by a user when starting encrypted communication in the network terminals according to Embodiments 1 and 2 of the present invention. 5 is an example of a screen used by a user when confirming the start of encrypted communication in the network terminals according to Embodiments 1 and 2 of the present invention. It is a block diagram which shows roughly the structure of the network terminal which concerns on Embodiment 2 of this invention. It is a sequence diagram which shows the operation | movement (namely, communication method which concerns on Embodiment 1) of the network terminal which concerns on Embodiment 2 of this invention. It is a block diagram which shows roughly the structure of the modification of the network terminal which concerns on Embodiment 1 and 2 of this invention. It is a block diagram which shows roughly the structure of the other modification of the network terminal which concerns on Embodiment 1 and 2 of this invention.

Embodiment 1 FIG.
FIG. 1 is a block diagram schematically showing configurations of network terminals 1a and 1b according to Embodiment 1 of the present invention (that is, network terminals that can implement the communication method according to Embodiment 1). The network terminal (A) 1a and the network terminal (B) 1b are terminals having a wireless network connection function, for example. As shown in FIG. 1, the network terminal 1a includes, as main components, a display device 2a, a display circuit 3a, and a key having a function as key management means for managing keys for encryption and decryption. Management unit 4a, data encryption / decryption unit 5a having a function as a data encryption unit and data decryption unit, and wireless transmission / reception unit having a function as a network transmission unit and a network reception unit that communicate via a network 6a, an infrared transmission / reception unit 7a having functions as an infrared transmission means and an infrared reception means for performing infrared communication, a key input circuit 8a, an input key 9a, and a data storage device 10a. The network terminal 1b includes, as main components, a display device 2b, a display circuit 3b, a key management unit 4b having a function as key management means for managing keys for encryption and decryption, data A data encryption / decryption unit 5b having functions as an encryption unit and a data decryption unit, a network transmission unit communicating via a network, a wireless transmission / reception unit 6b having a function as a network reception unit, and infrared communication It has an infrared transmission / reception unit 7b having a function as an infrared transmission means and an infrared reception means, a key input circuit 8b, an input key 9b, and a data storage device 10b.

  The display circuit 3a is a part that controls display for presenting a GUI to a user, and drives the display device 2a to display characters, graphics, image data, and the like. The display device 2a is, for example, a liquid crystal display, but may be another type of display device. The key management unit 4a generates and stores keys (encryption key and decryption key) necessary for encryption and decryption. The data encryption / decryption unit 5a uses the key received from the key management unit 4a to encrypt data to be transmitted when performing wireless communication, and also decrypts the received encrypted data. The wireless transmission / reception unit 6a performs wireless communication, that is, data transmission and reception. For example, a wireless LAN is used as the communication method, but a wireless communication system of another method may be used. The infrared transmitting / receiving unit 7a performs infrared communication, that is, transmission and / or reception of data using infrared rays. The key input circuit 8a inputs a command for the user to operate the network terminal using the input key 9a. The input key 9a is an input device that is actually operated by the user. For example, the input key 9a is a pointing device such as a keyboard or a mouse, a touch panel that directly inputs the user by touching the display device 2a, and the like. May be. The data storage device 10a is a storage device that stores data to be transmitted and received by the network terminal, and is, for example, a memory card such as a flash memory, an on-board memory device, or an auxiliary storage device such as an HDD. The data stored in the data storage device 10a is, for example, contents such as photographs and moving images, but may be other data. In addition, you may provide the audio | voice output circuit and audio | voice output apparatus (not shown) for outputting the network terminal 1a audio | voice. Each configuration of the network terminal 1b has the same function as that of the network terminal 1a. However, each configuration of the network terminal 1a and the network terminal 1b may have different functions.

  Next, an operation in which the network terminal 1a transmits data to the counterpart network terminal 1b and receives data from the network terminal 1b will be described. First, the infrared transmission / reception unit 7a of the network terminal 1a transmits at least one of the keys for encryption and decryption managed by the key management unit 4a to the infrared transmission / reception unit 7b of the network terminal 1b by infrared. . Next, the data encryption / decryption unit 5a of the network terminal 1a encrypts, for example, the first data stored in the data storage device 10a using a key managed by the key management unit 4a. The encryption at this time is encryption that can be decrypted using a key transmitted to the network terminal 1b by infrared rays. Next, the wireless transmission / reception unit 6a of the network terminal 1a transmits the encrypted first data to the network terminal 1b via the network.

  When the network terminal 1a receives data from the network terminal 1b, the wireless transmission / reception unit 6a of the network terminal 1a encrypts the transmitted second data using the key transmitted by the network terminal 1b with infrared rays. And received from the network terminal 1b via the network. Next, the data encryption / decryption unit 5a of the network terminal 1a decrypts the received second data using a key managed by the key management unit 4a of the network terminal 1a. Note that the key used for encryption by the data encryption / decryption unit 5a (5b) and the key used for decryption by the data encryption / decryption unit 5b (5a) are different from each other. There are certain methods, and the present invention can be applied to any method.

  Next, an operation in which the network terminal 1b receives data from the counterpart network terminal 1a and transmits data to the network terminal 1a will be described. First, the infrared transmission / reception unit 7b of the network terminal 1b receives at least one key among the keys for encryption and decryption managed by the partner network terminal 1a from the network terminal 1a by infrared. Next, the wireless transmission / reception unit 6b of the network terminal 1b receives the first data from the other network terminal 1a via the network. The first data at this time is data encrypted by the network terminal 1a so that it can be decrypted by using a key received by infrared rays, using a key managed by the key management unit 4a. Next, the data encryption / decryption unit 5b of the network terminal 1b decrypts the received first data using the key received by infrared rays.

  When the network terminal 1b transmits data to the network terminal 1a, the data encryption / decryption unit 5b of the network terminal 1b, for example, uses the infrared data to store the second data stored in the data storage device 10b. Encrypt using the received key. It should be noted that the key used for encryption by the data encryption / decryption unit 5b (5a) and the key used for decryption by the data encryption / decryption unit 5a (5b) are different from each other. There are certain methods, and the present invention can be applied to any method. Next, the wireless transmission / reception unit 6b of the network terminal 1b transmits the encrypted second data to the counterpart network terminal 1a via the network.

  Next, the operation of the first embodiment will be described more specifically. FIG. 2 is a sequence diagram showing operations of network terminals 1a and 1b according to Embodiment 1 (that is, a communication method according to Embodiment 1). 3 is a screen example of the display device 2a used by the user when starting encrypted communication in the network terminal 1a, and FIG. 4 is a view for checking the start of encrypted communication in the network terminal 1b. 6 is a screen example of the display device 2b used by the user.

  In the description of FIG. 2, a case where the common key method is used as the encryption method will be described. First, the user performs an encryption key exchange start operation by operating the infrared port of the infrared transmission / reception unit 7a of the wireless communication terminal 1a toward the infrared port of the infrared transmission / reception unit 7b of the network terminal 1b (step S100). The operation in this case is, for example, an operation of pressing the input key 9a in accordance with the GUI displayed on the display device 2a. The encryption key exchange start operation is completed by selecting and confirming the “Yes” button using the input key 9a on the GUI screen shown in FIG. As a result of the operation, the network terminal 1a transmits the key (encryption key in the example of FIG. 2) read from the key management unit 4a to the network terminal 1b via the infrared transmission / reception unit 7a by infrared communication (step) S101). After receiving the encryption key via the infrared transmission / reception unit 7b, the network terminal 1b displays a confirmation screen as shown in FIG. 4 on the display device 2b by the display circuit 3b (step S102). Next, on the GUI screen for confirmation shown in FIG. 4, the user selects a “Yes” button using the input key 9b and performs a confirmation operation (step S103). In response to this confirmation operation, the network terminal 1b stores the received encryption key in the key management unit 4b, and then transmits an encryption key receipt response message to the network terminal 1a via the wireless transmission / reception unit 6b. (Step S104). When the network terminal 1a receives the encryption key receipt response via the wireless transmission / reception unit 6a, a common encryption key is determined between the network terminal 1a and the network terminal 1b. The encrypted communication using the encryption key can be performed (step S105 and subsequent steps).

  When data is transmitted from the network terminal 1a to the network terminal 1b, the data read from the data storage device 10a is encrypted by the data encryption / decryption unit 5a using the encryption key by the network terminal 1a, and then wirelessly transmitted. The encrypted data is transmitted from the transmission unit 6a to the network terminal 1b. The network terminal 1b uses the data encryption / decryption unit 5b to decrypt the encrypted data received via the wireless transmission unit 6b using the encryption key. When data is transmitted from the network terminal 1b to the network terminal 1a, the data read from the data storage device 10b is conversely encrypted by the data encryption / decryption unit 5b by the network terminal 1b using the encryption key. The encrypted data is transmitted from the wireless transmission unit 6b to the network terminal 1a. The network terminal 1a uses the data encryption / decryption unit 5a to decrypt the encrypted data received via the wireless transmission unit 6a using the encryption key.

  As described above, according to the network terminals 1a and 1b according to the first embodiment (or the communication method according to the first embodiment), there is a low and simple possibility that a key is leaked between the network terminals 1a and 1b. Key exchange can be performed safely by operation. Also, by using infrared communication for key transfer, encrypted communication can be performed without the need for the user to replace an authentication card or the like.

  In this embodiment, the example in which the encrypted communication is performed using wireless is described, but a wired network such as a LAN may be used instead of the wireless communication.

Embodiment 2. FIG.
FIG. 5 is a block diagram schematically showing configurations of network terminals 21a and 21b according to Embodiment 2 of the present invention (that is, network terminals that can implement the communication method according to Embodiment 1). The network terminal (A) 21a and the network terminal (B) 21b are terminals having a wireless network connection function, for example. In FIG. 5, the same or corresponding components as those in FIG. In the second embodiment, the key managers 24a and 24b use a first key (for example, a one-time key) and a second key (regular key) as at least one key for encryption and decryption. Manage.

  First, an operation in which the network terminal 21a transmits data to the network terminal 21b and receives data from the network terminal 21b will be described. The infrared transmission / reception unit 7a of the network terminal 21a transmits the first key included in the encryption / decryption key managed by the key management unit 24a to the infrared transmission / reception unit 7b of the counterpart network terminal 21b by infrared. . Next, the data encryption / decryption unit 5a of the network terminal 21a encrypts the second key included in the key managed by the key management unit 24a using the key managed by the key management unit 24a. The encryption at this time is encryption of a method that can be decrypted using the first key. Next, the wireless transmission / reception unit 6a of the network terminal 21a transmits the encrypted second key to the partner network terminal 21b via the network. Next, the data encryption / decryption unit 5a of the network terminal 21a uses, for example, the first key stored in the data storage device 10a using the key managed by the key management unit 24a. Is encrypted so that it can be decrypted. Next, the wireless transmission / reception unit 6a of the network terminal 21a transmits the encrypted first data to the counterpart network terminal 21b via the network.

  When the network terminal 21a receives data from the network terminal 21b, the wireless transmission / reception unit 6a of the network terminal 21a encrypts and transmits the second transmitted by the counterpart network terminal 21b using the transmitted second key. Is received from the other party's network terminal 21 via the network. Next, the data encryption / decryption unit 5a of the network terminal 21a decrypts the received second data using the key managed by the key management unit 24a.

  Next, an operation in which the network terminal 21b receives data from the counterpart network terminal 21a and transmits data to the network terminal 21a will be described. The infrared transmission / reception unit 7b of the network terminal 21b receives the first key included in the encryption / decryption key managed by the partner network terminal 21a from the partner network terminal 21a by infrared. Next, the wireless transmission / reception unit 6b of the network terminal 21b receives the encrypted second key from the wireless transmission / reception unit 6a of the counterpart network terminal 21a via the network using the key managed by the counterpart network terminal 21a. To do. The encryption at this time is encryption of a method that can be decrypted using the first key. Next, the data encryption / decryption unit 5b of the network terminal 21b decrypts the encrypted second key using the first key received by infrared rays. Next, the wireless transmission / reception unit 6b of the network terminal 21b uses the key managed by the other party's network terminal 1a to encrypt and transmit the first data transmitted to the other party using the second key. Received from the network terminal 21a via the network. Next, the data encryption / decryption unit 5b of the network terminal 21b performs a process of decrypting the received first data using the decrypted second key.

  When the network terminal 21b transmits data to the network terminal 21a, the data encryption / decryption unit 5b of the network terminal 21b decrypts, for example, the second data stored in the data storage device 10b. The encrypted second key is used for encryption. Next, the wireless transmission / reception unit 6b of the network terminal 21b transmits the encrypted second data to the partner network terminal 21a via the network.

  Next, the operation of the second embodiment will be described more specifically. FIG. 6 is a sequence diagram showing operations of the network terminals 21a and 21b according to the second embodiment of the present invention (that is, the communication method according to the second embodiment). In the second embodiment, the encryption key (first key) transmitted by infrared communication is not used for data encryption, but is used only when exchanging a regular key (second key). Will be described. In the description of FIG. 6, a case where a common key method is used as an encryption method will be described.

  The operations in steps S101 to S104 in FIG. 6 are the same as the operations in steps S101 to S104 in FIG. 2 except that the key transmitted by infrared is a one-time key.

  The network terminal 21a reads the regular encryption key (second key) used for data communication from the key management unit 24a and transmits it to the network terminal 21b via the wireless transmission / reception unit 6a (step S205). The network terminal 21b stores the normal encryption key received via the wireless transmission / reception unit 6b in the key management unit 24b, and then sends a normal encryption key receipt response message to the network terminal 21a via the wireless transmission / reception unit 6b. Is transmitted (step S206). When the network terminal 21a receives the normal encryption key receipt response via the wireless transmission / reception unit 6a, a common normal encryption key is determined between the network terminal 21a and the network terminal 21b. Encrypted communication using the regular encryption key (second key) can be performed between the two (step S207 and subsequent steps).

  When transmitting data from the network terminal 21a to the network terminal 21b, after the network terminal 21a encrypts the data read from the data storage device 10a with the data encryption / decryption unit 5a using the regular encryption key, The encrypted data is transmitted from the wireless transmission unit 6a to the network terminal 1b. The network terminal 21b uses the data encryption / decryption unit 5b to decrypt the encrypted data received via the wireless transmission unit 6b using the regular encryption key. When data is transmitted from the network terminal 21b to the network terminal 21a, the data read from the data storage device 10b is conversely encrypted by the data encryption / decryption unit 5b using the regular encryption key. Thereafter, the encrypted data is transmitted from the wireless transmission unit 6b to the network terminal 21a. The network terminal 21a uses the data encryption / decryption unit 5a to decrypt the encrypted data received via the wireless transmission unit 6a using the regular encryption key.

  As described above, according to the network terminals 21a and 21b (or the communication method) according to the second embodiment, there is a low possibility that the key is leaked between the network terminals 21a and 21b, and the key can be safely and easily operated. Exchanges can be made. Also, by using infrared communication for key transfer, encrypted communication can be performed without the need for the user to replace an authentication card or the like. Further, by shortening the key length of the one-time key and increasing the key length of the regular encryption key, there is an effect that a strong encryption can be used for data communication.

  In the second embodiment, points other than those described above are the same as those in the first embodiment.

Modified example.
FIG. 7 is a block diagram schematically showing a configuration of a modified example of the network terminals 31a and 31b according to the first and second embodiments of the present invention. In FIG. 7, the same or corresponding components as those in FIG. 1 or FIG. In FIGS. 1 and 5, the example in which the network terminals 1a (21a) and 1b (21b) have infrared transmission / reception units 7a and 7b as ports for performing infrared communication has been described. However, as shown in FIG. The configuration may be such that 31a has the infrared transmission unit 11a and the network terminal 31b has the infrared reception unit 12b. In this case, infrared communication is not bidirectional communication, but unidirectional communication from the network terminal 31a to the network terminal 31b.

  FIG. 8 is a block diagram schematically showing a configuration of another modification of the network terminals 41a and 41b according to the first and second embodiments of the present invention. In FIG. 8, the same reference numerals are given to the same or corresponding components as those in FIG. 1 or FIG. 1 and 5, the network terminals 1a (21a) and 1b (21b) have been described as having wireless transmission / reception units 6a and 6b, respectively. However, as shown in FIG. 8, the network terminal 41a is a wireless transmission / reception unit. The network terminal 41b is configured to be connected to the wireless network by the wired network (cable 14b) and the access point 14 via the network transmission / reception unit 13b via communication with the wireless access point 14 via 6a. May be. Conversely, the network terminal 41a may have a network transmission / reception unit, and the network terminal 41b may have a wireless transmission / reception unit.

1a, 1b, 21a, 21b, 31a, 31b, 41a, 41b Network terminal, 2a, 2b display device, 3a, 3b display circuit, 4a, 4b, 24a, 24b Key management unit, 5a, 5b Data encryption / decryption Unit, 6a, 6b wireless transmission / reception unit, 7a, 7b infrared transmission / reception unit, 8a, 8b key input circuit, 9a, 9b input key, 10a, 10b data storage device, 11a infrared transmission unit, 12b infrared reception unit, 13b wired network transmission / reception Part 14 wireless access point.

Claims (18)

A network terminal that communicates with a partner network terminal,
Key management means for managing keys for encryption and decryption;
Infrared transmission means for transmitting at least one key of the keys managed by the key management means to the counterpart network terminal by infrared;
Data encryption means for encrypting the first data using a key managed by the key management means so that the first data can be decrypted using the key transmitted by infrared rays;
A network terminal comprising: network transmission means for transmitting the encrypted first data to the counterpart network terminal via a network. Network receiving means for receiving the second data transmitted from the other party network terminal via the network by encrypting the other party network terminal using the key transmitted by infrared;
The network terminal according to claim 1, further comprising: a data decrypting unit that decrypts the received second data using a key managed by the key managing unit. A network terminal that communicates with a partner network terminal,
Infrared receiving means for receiving at least one key of encryption and decryption keys managed by the counterpart network terminal from the counterpart network terminal by infrared;
Network receiving means for receiving the first data transmitted from the counterpart network terminal via the network, encrypted using a key managed by the counterpart network terminal, encrypted using the key received by infrared rays, and transmitted; ,
A network terminal comprising: data decrypting means for decrypting the received first data using the key received by the infrared light. Data encryption means for encrypting second data using the infrared key received;
The network terminal according to claim 3, further comprising: network transmission means for transmitting the encrypted second data to the counterpart network terminal via a network. A network terminal that communicates with a partner network terminal,
Key management means for managing keys for encryption and decryption;
An infrared transmission means for transmitting the first key included in the key managed by the key management means to the counterpart network terminal by infrared;
A process of encrypting a second key included in a key managed by the key management unit using a key managed by the key management unit so that the second key can be decrypted using the first key; and Data encryption means for performing a process of encrypting the data in such a manner that the data can be decrypted using the second key using the key managed by the key management means,
A network that performs processing for transmitting the encrypted second key to the counterpart network terminal via a network, and processing for transmitting the encrypted first data to the counterpart network terminal via a network And a transmission means. Network receiving means for receiving the second data transmitted from the other party network terminal via the network, the second party network terminal encrypting using the transmitted second key, and transmitting the second data;
6. The network terminal according to claim 5, further comprising: a data decrypting unit that decrypts the received second data using a key managed by the key managing unit. A network terminal that communicates with a partner network terminal,
An infrared receiving means for receiving, from the other party network terminal, the first key included in the key for encryption and decryption managed by the other party network terminal by infrared;
A process of receiving an encrypted second key from the partner network terminal via the network so that the second key encrypted using the key managed by the partner network terminal can be decrypted, and the partner network A network receiving means for performing processing for receiving the first data transmitted from the counterpart network terminal via the network, encrypted using a key managed by the terminal, decryptable using the second key, and transmitted;
A process of decrypting the encrypted second key using the first key received by the infrared; and the received second data by decrypting the received first data. And a data decoding means for performing a decoding process using the network terminal. Data encryption means for encrypting second data using the decrypted second key;
The network terminal according to claim 7, further comprising: network transmission means for transmitting the encrypted second data to the counterpart network terminal via a network. The network terminal according to claim 1, wherein at least one of the network transmission unit and the network reception unit is a wireless communication unit. A communication method of a network terminal that communicates with a partner network terminal,
Transmitting at least one of keys for encryption and decryption managed by the network terminal to the counterpart network terminal by infrared;
Encrypting first data using a key managed by the network terminal so that the first data can be decrypted using the key transmitted by the infrared;
And transmitting the encrypted first data to the counterpart network terminal via a network. Receiving the second data encrypted by the counterpart network terminal using the infrared key and transmitted from the counterpart network terminal via a network; and
The communication method according to claim 10, further comprising: decrypting the received second data using a key managed by the network terminal. A communication method of a network terminal that communicates with a partner network terminal,
Receiving at least one of keys for encryption and decryption managed by the counterpart network terminal from the counterpart network terminal by infrared;
Using the key managed by the counterpart network terminal, encrypting the decrypted data using the key received by the infrared, and receiving the transmitted first data from the counterpart network terminal via the network;
And a step of decrypting the received first data using the key received by the infrared ray. Encrypting second data using the infrared key received;
The communication method according to claim 12, further comprising the step of transmitting the encrypted second data to the counterpart network terminal via a network. A communication method of a network terminal that communicates with a partner network terminal,
Transmitting the first key included in the key for encryption and decryption managed by the network terminal to the counterpart network terminal by infrared;
Encrypting a second key included in a key managed by the network terminal using a key managed by the network terminal so that the second key can be decrypted using the first key;
Transmitting the encrypted second key to the counterpart network terminal via a network;
Encrypting first data using a key managed by the network terminal so as to be decryptable using the second key;
And transmitting the encrypted first data to the counterpart network terminal via a network. Receiving the second data encrypted by the counterpart network terminal using the transmitted second key and transmitted via the network from the counterpart network terminal;
The communication method according to claim 14, further comprising: a data decryption unit configured to decrypt the received second data using a key managed by the network terminal. A communication method of a network terminal that communicates with a partner network terminal,
Receiving the first key included in the key for encryption and decryption managed by the counterpart network terminal from the counterpart network terminal by infrared;
Using the key managed by the counterpart network terminal, receiving the encrypted second key from the counterpart network terminal via the network so that it can be decrypted using the first key;
Decrypting the encrypted second key using the first key received in the infrared;
Using the key managed by the counterpart network terminal, receiving the first data transmitted from the counterpart network terminal via the network, encrypted and transmitted so as to be decryptable using the second key;
And a step of decrypting the received first data using the decrypted second key. Encrypting second data using the decrypted second key;
The communication method according to claim 16, further comprising a step of transmitting the encrypted second data to the counterpart network terminal via a network. The communication method according to any one of claims 10 to 17, wherein at least one of the step of transmitting via the network and the step of receiving via the network is a step by wireless communication.

Images