JP2002271313A - Encipherment communication system, its encipherment communication method and forming method of its encipherment key - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable safe encipherment communication which requires no complicated operations. SOLUTION: Key information necessary for forming a cryptographic key is stored in a key information storing means 210 of transmitting equipment 200 and a key information storing means of a receiving equipment 300. A cryptographic code generator 100 generates arbitrary cryptographic codes and sends then to the transmitting equipment 200 and the receiving equipment 300. A cryptographic key forming means 220 of the transmitting equipment 200 applies obtained cryptographic codes to key information stored in the key information storing means 210, and forms a cryptographic key. An encipherment means 230 forms encipherment data by using the cryptographic key, and transmits the data to the receiving equipment 300. Similarly to the transmitting equipment 22, the receiving equipment 300 forms a cryptographic key by a cryptographic key forming means 320. A decipherment means 330 deciphers encipherment data by using the formed cryptographic key, and regenerates original data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encrypted communication system, an encrypted communication method thereof, and a method of generating an encryption key, and more particularly to transmitting arbitrary information data from a transmitting device to a receiving device connected via a communication network. The present invention relates to an encryption communication system in which the information data is encrypted at that time and a method of generating an encryption communication method encryption key.

[0002]

2. Description of the Related Art In recent years, in offices, buildings, factories, and the like, Ethernet (registered trademark) (Ethernet) has been used.
(Registered trademark)), etc.
The system built in k) is widely used. A LAN system using Ethernet is characterized by being inexpensive and easy to construct, and is currently most widely used. In particular, computers in recent years have a function of connecting to a network, and can easily connect to a LAN and transfer various data using this network connection function.

FIG. 5 is a configuration diagram of a conventional LAN system. A terminal device A (300a), a terminal device B (300b), and a terminal device C (300c) are connected to a network 400 such as an Ethernet to exchange data. Devices such as a print server and a database server are connected to the network 400 as needed. At this time, when transmitting data that should not be leaked to the outside, the data is encrypted and transmitted.

In a commonly used encryption method, a common key for encrypting and decrypting data is provided in both devices for transmitting and receiving data. For example, the terminal device A (3
Assuming that 00a) is the transmitting side and the terminal device B (300b) is the receiving side, the terminal device A (300a) encrypts the data to be transmitted with a common key and transmits the data to the terminal device B (300b) via the network 400. Terminal device B (300b)
Receives this, decrypts it with the common key, and obtains data.
The common key is exchanged via the network 400 or some other method not via the network 400.

[0005]

However, the conventional communication system has a problem that packet data flowing through the network can be captured and the data can be easily decoded.

For example, when data is transmitted from the terminal device A (300a) to the terminal device B (300b) via the network 400, the data flows on the network 400. Therefore, the terminal device C (300c) transmits this data. You can easily capture and decrypt the data.

[0007] Even if the data is encrypted, if the common key is obtained by intercepting the distribution of the common key, the decryption can be easily performed. Even if the common key cannot be obtained, if the same common key is used repeatedly, it is possible to guess the common key by analyzing the encrypted data, and there is a risk that the data will be decrypted. There is. For this reason, a troublesome operation for management is required, such as a common key that needs to be periodically changed without using the network 400.

[0008] The present invention has been made in view of the above points, and an object of the present invention is to provide a secure encrypted communication system which does not require a troublesome operation and a method of generating an encrypted communication method encryption key. And

[0009]

According to the present invention, in order to solve the above-mentioned problem, when transmitting arbitrary information data from a transmitting device to a receiving device connected via a communication network, the information data is encrypted. In the encrypted communication system described above, an arbitrary encryption code applied to generation of an encryption key used for encrypting the information data is generated as necessary, and the encryption code is transmitted to the transmitting device and the receiving device. An encryption code generator, key information storage means for storing key information related to generation of an encryption key including a rule for generating the encryption key, and applying the encryption code obtained from the encryption code generator to the key information. Encryption key generating means for generating the encryption key by using the encryption key to generate the encrypted data by encrypting the information data using the encryption key. A transmitting device including an encrypting unit for transmitting to the receiving device; a key information storing unit for storing the key information; and the encryption by applying the encryption code obtained from the encryption code generation device to the key information. A receiving apparatus comprising: an encryption key generating means for generating a key; and a decrypting means for decrypting encrypted data obtained from the transmitting apparatus using the encryption key. Communication system is provided.

[0010] In the encryption communication system having such a configuration, the key information storage means of the transmitting device stores the key information relating to the generation of the encryption key including the rule necessary for generating the encryption key used for encrypting the arbitrary information data. Is stored. The same key information is also stored in the key information storage means of the receiving device that receives the information data from the transmitting device. The encryption code generation device generates an arbitrary encryption code used to generate an encryption key, and sends the encryption code to the transmission device and the reception device as needed, such as when a request is made from the transmission device. The encryption key generation means of the transmitting device applies the obtained encryption code to the key information stored in the key information storage means to generate an encryption key. The encryption unit encrypts the information data using the generated encryption key to generate encrypted data, and transmits the generated encrypted data to the receiving device. The encryption key generation means of the receiving device applies the obtained encryption code to the key information stored in the key information storage means to generate an encryption key, similarly to the transmission device. The decryption unit decrypts the acquired encrypted data using the generated encryption key, and restores the original data.

According to another aspect of the present invention, there is provided an encrypted communication method for encrypting information data when transmitting any information data from a transmitting device to a receiving device connected via a communication network. The transmitting device and the receiving device store in advance key information related to generation of an encryption key including a rule necessary for generating an encryption key used for encrypting the information data, and the encryption code generation device Generating an arbitrary encryption code to be used for generating the encryption key, and sending the generated encryption code to the transmitting device and the receiving device.The transmitting device acquires the encryption code, and stores the acquired encryption code in its own device. Generating the encryption key by applying to the key information stored in the storage device, encrypting the information data using the generated encryption key, and transmitting the encrypted data to the receiving device. And the receiving device acquires the encryption code, generates the encryption key by applying the acquired encryption code to the key information stored in the own device, receives the encrypted data, Decrypting the encrypted data using the generated encryption key.

In the encrypted communication method of such a procedure, both the transmitting device and the receiving device that encrypt and communicate information data include rules necessary for generating an encryption key used for encrypting information data in advance. The key information relating to the generation of the encryption key is stored. The encryption code generation device generates an arbitrary encryption code used for generating an encryption key as necessary, and sends the generated encryption code to the transmission device and the reception device. The transmitting device obtains an encryption code from the encryption code generation device, and generates an encryption key by applying the encryption code to the key information stored in the transmission device. continue,
The information data is encrypted using the generated encryption key, and the encrypted data is transmitted to the receiving device. On the other hand, the receiving device also acquires the encryption code, and generates an encryption key by applying the encryption code to the key information stored in the receiving device. Also, the received encrypted data is decrypted using the encryption key to restore the original data.

According to another aspect of the present invention, there is provided a method for generating an encryption key for encrypting information data when transmitting arbitrary information data from a transmitting device to a receiving device connected via a communication network. The transmitting device and the receiving device store in advance key information related to generation of an encryption key including a rule necessary for generation of an encryption key used for encryption and decryption of the information data, and the key information Generating an encryption key by applying the encryption code to the key information to obtain an encryption key for generating the encryption key by applying the encryption key. , Are provided.

In the method of generating an encryption key according to such a procedure,
The transmission device and the reception device store in advance key information related to generation of an encryption key including a rule necessary for generating an encryption key used for encryption and decryption of information data. Also, the transmitting device and the receiving device each obtain a common encryption code for generating an encryption key by applying the key information,
An encryption key is generated by applying the encryption code to the key information.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of an encryption communication system according to an embodiment of the present invention.

In the encryption communication system according to the present invention, a transmitting device 200 for transmitting arbitrary information data and a receiving device 300 for receiving the information data are connected via a communication network (not shown) such as Ethernet. , An encryption code generator 100 supplies an encryption code to each device.

The encryption code generation device 100 includes a transmission device 2
For example, at the time of a request from 00, an encryption code is generated as necessary and transmitted to the transmission device 200 and the reception device 300. A random number, for example, a number generated using a random number is generated as an encryption code. The generated encryption code is transmitted to the transmitting device 200 and the receiving device 300 via the communication network. The encryption code is a random number such as a random number, and since the encryption key cannot be inferred from the encryption code, it can be transmitted via a communication network. Also, in the figure, the encryption code generation device 100 is an independent device, but the transmission device 200 or the reception device 300
It may be configured to be incorporated in any of the above.

The transmitting apparatus 200 includes a key information storage unit 210 for storing key information for generating an encryption key, an encryption key generation unit 220 for generating an encryption key from the key information and the encryption code,
And encryption means 230 for encrypting arbitrary information data using the generated encryption key.

The key information storage means 210 is a storage device for storing key information necessary for generating an encryption key such as a rule or an arithmetic expression. The key information is a rule or the like when encrypting the original data. For example, when an encryption algorithm is employed in which extra redundant data is appropriately inserted into the original data string to perform encryption, "an arbitrary length of the original data string at a certain interval length is used. In this case, an arithmetic expression for calculating the redundant data length or the redundant data length of the redundant data to be inserted is defined and stored. This operation expression is a function using the encryption code as a variable. Alternatively, some rules may be stored, and one of them may be selected using an encryption code. In any case, the encryption algorithm is determined according to the encryption code, such as applying the encryption code to an arithmetic expression or the like.

The encryption key generation means 220 may transmit the desired data to the encryption code generation device 10 if necessary.
An encryption code is obtained from 0, an encryption key is generated by applying the encryption code to the key information, and the generated encryption key is output to the encryption unit 230. For example, a number generated by using a random number as an encryption code is obtained, and the encryption code is applied to an arithmetic expression for calculating the interval length of redundant data and the redundant data length to calculate each value. Assuming that the calculated redundant data interval length is b and the redundant data length is c, this is applied to the above rule, and "c redundant data is inserted for every b data into the original data string. ”Is generated. Here, the encryption algorithm is synonymous with the encryption key.

The encryption means 230 includes an encryption key generation means 22
Using the encryption key obtained from 0, the information data to be transmitted is encrypted to generate encrypted data. The encrypted data is transmitted to the receiving device 300.

The receiving apparatus 300 includes a key information storage unit 310 for storing key information for generating an encryption key, an encryption key generation unit 320 for generating an encryption key from key information and an encryption code,
And decryption means 330 for decrypting the encrypted data with the generated encryption key.

The key information storage means 310
This is a storage device in which the same key information as the key information storage means 210 is stored. The encryption key generation unit 320 generates an encryption key in the same procedure as the encryption key generation unit 220 of the transmitting device 200. The same encryption code as that of the transmission device 200 is sent from the encryption code generation device 100 to the encryption key generation means 320. Therefore, the encryption key generated by the encryption key generation unit 320 is the same as the encryption key generated by the encryption key generation unit 220 of the transmitting device 200.

The decrypting means 330 obtains the encrypted data transmitted from the transmitting device 200 and decrypts the encrypted data with the encryption key generated by the encryption key generating means 320.
The operation of the encrypted communication system having such a configuration and the encrypted communication method will be described.

The key information storage means 210 of the transmitting apparatus 200 and the key information storage means 310 of the receiving apparatus 300 store rules or arithmetic expressions for generating an encryption key.
When information data is transmitted from the transmitting device 200 to the receiving device 300, the encryption key generation unit 22 of the transmitting device 200
0 requests the encryption code generator 100 for an encryption code. The encryption code generation device 100 generates a random encryption code using a random number or the like, and
And to the receiving device 300. The encryption key generation means 220 of the transmitting device 200 acquires the encryption code, generates an encryption key by applying the encryption code to the key information, and generates the encryption key.
Send to The encrypting unit 230 encrypts the information data to be transmitted using the encryption key, and transmits the encrypted data to the receiving device 300. The encryption key generation unit 320 of the reception device 300 acquires the encryption code, applies the encryption code to the key information, generates an encryption key, and sends the encryption key to the decryption unit 330, similarly to the transmission device 200. The decrypting means 330 decrypts the encrypted data obtained from the transmitting device 200 using the encryption key.

In the above-described encryption communication system, key information is stored in the transmission device 200 and the reception device 300, and the encryption key is generated based on the key information. Even if it is captured, the encryption key cannot be obtained. In addition, every time the transmitting device 200 and the receiving device 300 are connected or each time data is transmitted, an encryption code is generated and a new encryption key is generated.
Even if data is captured and analyzed, the encryption key cannot be inferred. Furthermore, there is no new cost for storing the encryption key. As described above, according to the present invention, confidential data can be transmitted and received within the LAN without increasing costs.

Next, regarding the details of the generation and encryption of the encryption key, the function of the
This will be explained with the client-server system incorporated in the system. FIG. 2 is a configuration diagram of a client server system according to an embodiment of the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. In this system,
Data having confidentiality, that is, data requiring encryption is transmitted from the client 201 to the server 301. In the figure, the server 301 and the client 201 are connected on a one-to-one basis, but a configuration in which a plurality of clients 201 are connected to the server 301 may be adopted. In addition, as an encryption method,
It employs an algorithm that inserts meaningless redundant data according to a certain rule.

The client 201 has a key information storage unit 2
10, an encryption key generation unit 220, an encryption unit 230, and a communication control unit 240 for performing communication control.
The key information storage means 210 stores rules for encryption. Here, key information necessary for generating an encryption algorithm for inserting random redundant data having no meaning according to a certain rule is recorded in the original data string. For example, "For the original data string, a
C pieces of redundant data are inserted for every interval length b from the second data. Is stored. a designates a start position at which the insertion of redundant data is started, that is, an offset. b designates the interval length for inserting redundant data. c
Specifies the redundant data length of the redundant data to be inserted. Further, the key information storage means 210 stores arithmetic expressions for determining the values of a, b, and c. The arithmetic expression uses the encryption code as a variable, and a, b, and c can be calculated by applying the encryption code (random number) to the arithmetic expression. For example, an arithmetic expression is as follows, where an encryption code (random number) is y.

[0029]

F (y) = ((2 × y) +124) ÷ 3 + 1 (1) where the remainder of the function of equation (1) is a,
Set to b and c. Here, it is assumed that the arithmetic expressions are the same, but the arithmetic expressions may be set individually. Further, constants (here, 124) and operators of the arithmetic expression may be set by the encryption code. For example, a numerical value obtained as an encryption code can be a constant. When the operator is set to an encryption code, for example, the encryption code corresponding to the operator is substituted into Expression (1), and when the remainder is 1, plus (+), and when the remainder is 2, minus (-).
Thus, the conversion method is determined in advance.

The encryption key generation means 220 is provided for the communication control means 2
The encryption code obtained via 40 is applied to the above-described rules or arithmetic expressions to determine an encryption algorithm. For example, as an encryption code corresponding to b, an integer “1234”
When "5678" is set, when this value is applied to equation (1), b becomes "2", that is, the data interval length becomes "2". Similarly, a and c correspond to a and c. The encryption code can be applied to equation (1) to calculate a and c. For example, suppose that a = 1 and c = 3 in the same procedure as in b. "The redundant data is inserted from the beginning (first data) into the original data string, and three redundant data are inserted every interval length 2". Of course, these numbers will vary with changes in the encryption code.

The encryption means 230 includes an encryption key generation means 22
The information data is encrypted in accordance with the generated encryption algorithm of "0". For example, if the information data is "ABCD
If EFGHIJKLMNOPQRSTUVWXYZ "," A *** BC according to the encryption algorithm
*** DE **** FG *** HI ** JK ** LM
*** NO *** PQ *** RS ** TU *** VW
Redundant data called “*** XY *** Z” (* indicates redundant data) is generated. This redundant data is used as encrypted data by the server 301 via the communication control means 240.
Send to

Communication control means 240 connects to a communication network and controls data transmission and reception with server 301. The encryption code received from the server 301 is sent to the encryption key generation means 220. Further, the encrypted data encrypted by the encryption unit 230 is transmitted to the server 30.
Send to 1.

The server 301 comprises an encryption code generation means 101 for generating an encryption code, a key information storage means 310, an encryption key generation means 320, a decryption means 330, and a communication control means 340 for performing communication control.

The encryption code generation means 101 has the same function as the encryption code generation device 100, and
For example, when a connection request is received from the server 1, an encryption code is generated as needed. The encryption code is generated by the encryption key generation means 32
0 and the client 20 via the communication control means 340
Sent to 1.

The key information storage means 310
The key information storage unit 210 stores the same key information as the key information storage unit 210, and the encryption key generation unit 320 generates an encryption key in the same procedure as the encryption key generation unit 220 of the client 201.

The decryption means 330 is provided for the encryption key generation means 32
In accordance with the encryption algorithm generated by 0, redundant data is deleted to obtain original information data. The communication control means 340 connects to the communication network and
The transmission / reception of data to / from the client 201 is controlled, and the encryption code generated by the encryption code generation means 101 is transmitted to the client 201. Also, the client 201
, And sends the encrypted data to the decryption means 330.

The operation of the client server system having such a configuration and an encrypted communication method will be described. FIG. 3 is a block flow of an encrypted communication method according to an embodiment of the present invention. The same components as those in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted.

When the client 201 connects to the server 301, a request for an encryption code is made (S01). The server 301 generates a number generated using a random number as an encryption code, and transmits the generated number to the client 201 (S0
2). The client 201 generates an arithmetic expression using the encryption code based on the rule (S03). For example, a rule for setting the constant part of the above-described equation (1) using an encryption code is determined in advance, and the constant part is determined based on this rule to generate an arithmetic expression. Alternatively, a rule for setting an operator of an arithmetic expression using an encryption code is determined in advance, and an operator is determined based on this rule to generate an arithmetic expression. There is also a method of preparing several arithmetic expressions and selecting one according to the encryption code. Note that the step of generating the arithmetic expression in step S03 based on the rule may be omitted.

After the operation formula is determined, the values to be made redundant (offset, interval length, redundant data length) are determined (S
04). The offset, interval length, and redundant data length are calculated by applying the encryption code to the arithmetic expression generated in step S03 or an arithmetic expression prepared in advance. continue,
Based on the determined offset, interval length, and redundant data length, redundant data is inserted into the data to be transmitted to make the data redundant (S05). The redundant data is transmitted to the server 301 (S06).

The server 301 obtains the redundant data, and generates an arithmetic expression based on the rule using the encryption code given to the client 201 (S07). The generation of the arithmetic expression is the same as the procedure performed in step S03 of the client 201. Subsequently, the redundant numerical values (offset, interval length, redundant data length) are determined (S0).
8). The judgment of the redundant numerical value is performed by the client 201.
Is the same as the procedure performed in step S04. Next, based on the determined redundant numerical value, extra data is omitted from the received redundant data (S09). As a result, extra data is deleted from the redundant data, and decoding of the data is successful (S10).

When the client 201 has opened a port to the server 301, the exchange of transmitted / received data is continued based on the encryption algorithm corresponding to the calculated numerical value. If either line is closed, the above numerical value becomes invalid, and if the line is connected again, a new encryption code (random number) is issued, and data is transmitted and received using an encryption algorithm based on the new numerical value. .

Next, a method of generating an encryption key and encryption / decryption will be described with a specific example. FIG. 4 is an example of encryption key generation and encryption / decryption. Key information storage means 210 of client 201 and key information storage means 31 of server 301
In 0, key information is stored. In the key information, a correspondence between an arithmetic expression for calculating a numerical value (offset, interval length, redundant data length) used for redundancy and each encryption code applied to the arithmetic expression is described. In other words, rules are applied to apply arithmetic codes to determine the offset, encryption code 2 to determine the interval length, and encryption code 3 to determine the redundant data length, respectively. The rules are stored in the form of a program or the like.
From the encryption code generation means 101, an encryption code 1 ("000012234") applied to the offset, an encryption code 2 ("12345678") applied to the interval length, and an encryption code 3 ("11111111") applied to the redundant data length.
1 ″) is generated and sent to the encryption key generation unit 220 of the client 201 and the encryption key generation unit 320 of the server 301. The encryption key generation units 220 and 330 apply the encryption code to the arithmetic expression, and The offset, interval length, and redundant data length are determined, where the offset is 1, which is derived from the encryption code 1 ("0000001234"), the interval length is 2, which is derived from the encryption code 2 ("12345678"), and the redundant data length is encryption. Code 3 (“1111
311 derived from “1111”) is set. With this, an encryption algorithm “3 redundant data are inserted every two data from the end of the first data” is determined. .

For the encrypted data, the encryption means 230 converts the information data into "ABCDEFGHIJKLMNOP".
If QRSTUVWXYZ is used, "A *** BC *
** DE **** FG *** HI ** JK ** LM
** NO ** PQ ** RS ** TU *** VW *
** XY **** Z ".

In the decoding, the * of the redundant data is deleted by the decoding means 330 and converted to the original data. As described above, since the rule of redundancy, that is, the encryption algorithm changes according to the encryption code, data cannot be easily analyzed only by capturing data packets flowing through the LAN. Also, the unique data is difficult to decipher because the packet data length changes according to the rule of redundancy.

In the above description, information data transmitted from the client 201 to the server 301 is encrypted. However, information data transmitted from the server 301 to the client 201 may be encrypted. In this case, for example, the server 301 transmits the encryption code together with the encrypted data. The client 201 generates an encryption key using the encryption code, and decrypts the encrypted data. Also, here, the parameters of the offset, interval length, and redundant data length are determined from the encryption code.
Arbitrary parameters can be selected as needed. Further, the number of parameters determined by the encryption code can be increased. As described above, by defining some parameters according to the encryption code and setting the encryption algorithm, it is possible to perform complicated encryption and make decryption difficult.

The above processing functions can be realized by a computer. In this case, the processing content of the function that the encryption communication system should have is described in a program recorded on a computer-readable recording medium. Then, by executing this program on a computer, the above processing is realized on the computer. As a computer-readable recording medium,
There are a magnetic recording device and a semiconductor memory. When distributing to the market, CD-ROM (Compact Disc Read Only Me
mory) or a floppy (registered trademark) disk or the like, and stores and distributes the program in a portable recording medium. Alternatively, the program can be stored in a storage device of a computer connected via a network, and can be transferred to another computer via the network. When the program is executed by the computer, the program is stored in a hard disk device or the like in the computer, and is loaded into the main memory and executed.

[0047]

As described above, in the encryption communication system according to the present invention, the transmitting device and the receiving device store the same key information for generating the encryption key. The encryption code generator generates an encryption code as necessary and sends it to the transmitting device and the receiving device. The transmitting device and the receiving device generate an encryption key by applying the obtained encryption code to the key information. The transmitting device generates encrypted data using the generated encryption key and transmits the encrypted data to the receiving device. The receiving device decrypts the received encrypted data using the generated encryption key.

As described above, key information is stored in the transmitting apparatus and the receiving apparatus in advance, and an encryption code is generated at the time of data transmission or the like, and an encryption key is generated using each of them.
Since there is no need to directly transmit the encryption key, the encryption key can be stored safely. Further, since the encryption key is not likely to be decrypted even when transmitted through the communication network, the encryption code can be transmitted through the communication network, and there is no need to perform an operation that is cumbersome to transmit the encryption key. . Since data is transmitted and received by performing encryption using such an encryption key, secure data transmission and reception is possible.

In the encrypted communication method of the encrypted communication system according to the present invention, key information for generating an encryption key is stored in both the transmitting device and the receiving device. The encryption code generation device generates an arbitrary encryption code as necessary, and sends it to the transmission device and the reception device. The transmitting apparatus generates an encryption key by applying the obtained encryption code to the key information stored in the transmission apparatus, and encrypts the information data using the encryption key. The encrypted data is transmitted to the receiving device. The receiving device generates an encryption key in a similar procedure, and decrypts the encrypted data using the encryption key.

As described above, the key information is held in the transmitting apparatus and the receiving apparatus in advance, and an encryption code is generated at the time of data transmission or the like, and an encryption key is generated using each code.
Since there is no need to directly transmit the encryption key, the encryption key can be stored safely. Further, since the encryption key is not likely to be decrypted even when transmitted through the communication network, the encryption code can be transmitted through the communication network, and there is no need to perform an operation that is cumbersome to transmit the encryption key. . Since data is transmitted and received by performing encryption using such an encryption key, secure data transmission and reception is possible.

In the encryption key generation method of the present invention, key information for generating an encryption key used for encrypting and decrypting information data is stored in advance. If necessary, an encryption code common to the transmission side and the reception side is obtained, and the encryption code is applied to the key information to generate an encryption key.

As described above, the key information is stored in the transmitting side and the receiving side in advance, an encryption code is generated at the time of data transmission or the like, and an encryption key is generated using each of them. Since there is no need to directly transmit the encryption key, the encryption key can be stored safely. Further, since the encryption key is not likely to be decrypted even when transmitted through the communication network, the encryption code can be transmitted through the communication network, and there is no need to perform an operation that is cumbersome to transmit the encryption key. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an encryption communication system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a client server system according to an embodiment of the present invention.

FIG. 3 is a block flow of an encrypted communication method according to an embodiment of the present invention.

FIG. 4 is a diagram showing an example of encryption key generation and encryption / decryption.

FIG. 5 is a configuration diagram of a conventional LAN system.

[Explanation of symbols]

100: code generator, 200: transmitter, 2
10 ... key information storage means, 220 ... encryption key generation means, 230 ... encryption means,
300 ... receiving device, 3 10 ... key information storage means, 320 ... encryption key generation means, 3
30... Decoding means

Claims (11)

[Claims] 1. An encrypted communication system in which, when transmitting arbitrary information data from a transmitting device to a receiving device connected via a communication network, the information data is encrypted, if necessary, the information data An encryption code generator that generates an encryption code to be applied to the generation of an encryption key used for encryption, and sends the encryption code to the transmitting device and the receiving device; and a rule for generating the encryption key. Key information storage means for storing key information related to generation of an encryption key including: an encryption key generation means for generating the encryption key by applying the encryption code obtained from the encryption code generation device to the key information; Encrypting the information data using an encryption key to generate encrypted data and transmitting the encrypted data to the receiving device. A key information storage unit that stores the key information; an encryption key generation unit that generates the encryption key by applying the encryption code obtained from the encryption code generation device to the key information; And a decryption means for decrypting the encrypted data obtained from the transmitting device by using the receiving device. 2. The encrypted communication system according to claim 1, wherein the encrypted communication system generates random data by inserting random redundant data into the information data, and stores key information of the transmitting device and the receiving device. The means determines an offset that determines a position where insertion of redundant data is started in a data string of the information data, an interval length that determines an interval between the data strings in which the redundant data is inserted, or a length of the redundant data to be inserted. A rule for setting a redundant data length is stored as key information, and the encryption key generation means of the transmitting device and the receiving device apply the obtained encryption code to the rule to apply the offset, the interval length, or the redundancy. An encryption key is generated by determining a data length, and the encryption unit of the transmitting device adds the redundant information to the data sequence of the information data in accordance with the generated encryption key. Generating redundant data into which the long data has been inserted, as encrypted data, and decrypting means of the receiving device decrypts the original information data by deleting the redundant data from the encrypted data according to the generated encryption key. 2. The encrypted communication system according to claim 1, wherein: 3. The encrypted communication according to claim 2, wherein the key information has information on a function for calculating the offset, the interval length, or the redundant data length using the encryption code as a variable. system. 4. The encrypted communication system according to claim 3, wherein the information on the function further has a rule for setting a constant part according to the encryption code. 5. The encrypted communication system according to claim 3, wherein the information on the function further has a rule for setting an operator according to the encryption code. 6. The encryption communication system according to claim 1, wherein the encryption code generator generates a random numerical value generated by using a random number as the encryption code. 7. The encryption communication system according to claim 1, wherein the encryption code generation device is incorporated in the transmission device or the reception device. 8. The encryption key generation means of the transmission device requests the encryption code generation device for a new encryption code each time the connection with the reception device is started. 2. The encrypted communication system according to 1. 9. An encrypted communication method for encrypting information data when transmitting any information data from a transmitting device to a receiving device connected via a communication network, wherein the transmitting device and the receiving device are: Key information relating to the generation of an encryption key including a rule necessary for generation of an encryption key used for encrypting the information data is stored in advance, and the encryption code generator is used to generate the encryption key as necessary. A step of generating an arbitrary encryption code and sending it to the transmission device and the reception device; and the transmission device acquires the encryption code, and applies the acquired encryption code to the key information stored in the own device. Generating the encryption key, encrypting information data using the generated encryption key, and transmitting the encrypted data to the receiving device. Obtain the encryption code, generate the encryption key by applying the obtained encryption code to the key information stored in the own device, receive the encrypted data, using the generated encryption key Decrypting the encrypted data. 10. A method for generating an encryption key for encrypting information data when transmitting arbitrary information data from a transmitting device to a receiving device connected via a communication network, wherein the transmitting device and the receiving device However, in advance, key information relating to generation of an encryption key including a rule necessary for generation of an encryption key used for encryption and decryption of the information data is stored, and by applying to the key information, A method for generating an encryption key, comprising: obtaining an arbitrary encryption code to be generated together; and applying the encryption code to the key information to generate the encryption key. 11. A program for causing a computer to execute a process of generating an encryption key for encrypting information data when transmitting any information data from a transmission device to a reception device connected via a communication network. By storing in advance in the computer key information related to generation of an encryption key including a rule necessary for generation of an encryption key used for encryption and decryption of the information data, and applying the key information to the key information. A program for acquiring an arbitrary encryption code for generating the encryption key, and executing a procedure for generating the encryption key by applying the encryption code to the key information.