JPH06152590A - Encipherment system - Google Patents

Abstract

PURPOSE:To provide an encipherment system where changed parts are not easily found even when part of information to be ciphered is changed. CONSTITUTION:An addition information generation means 2 generates addition information 3 related to all data from the data string of information 1 to be ciphered. The generated addition information 3 is added to the data string of the information 1 to be ciphered. A process means 4 generated a new data string 5 by processing respective data of information 1 and 3 to be ciphered by ciphered with additional information 3 means of preceding or following data. A ciphering means 7 adds the random number series generated by a random number series generation means 6 to the data string 5, resulting in generating the ciphered data string 8. When part of the data string to be ciphered is changed, the entire ciphered data string is changed so that the changed part becomes hard to find.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION In the field of computer information encryption, it is often the case that the encrypted information is inversely encrypted (decrypted), the encrypted information is partially changed, and then encrypted again. In such a case, in order to increase the confidentiality of the encrypted information, an encryption method that makes it difficult to know which part of the encrypted information has been changed is required.

The present invention relates to an encryption system for computer information, and more particularly, to computer data in which even if a part of the information encrypted as described above is changed, it is not easy to know what has been changed. It is related to the encryption method of.

[0003]

2. Description of the Related Art In communication between computers such as personal computer communication, an identifier such as a machine number of a personal computer or a workstation and data contents are encrypted and transmitted in order to maintain confidentiality of data and the like. There is. FIG. 5 is a diagram showing a conceptual diagram of the above-mentioned data transmission system between computers, 11 is a computer, 11a is an encryption means, 11b is a random number sequence generation means, 11c is a computer number, a sender code, etc. An identifier and transmission data, 12 is a modem, and 13 is a communication line between computers.

In FIG. 1, the machine number of the computer that needs to be kept confidential, generated in the computer 11,
The identifier of the sender or the like and the transmission data 11c or the like are given to the encryption means 11a. The encryption means 11a uses the random number sequence generated by the random number sequence generation means 11b to encrypt the transmission data 11c and the like. The encrypted transmission data and the like are modulated by the modem 12 and transmitted to another computer or the like via the communication line 13.

In the data communication as described above, as a data encryption method, conventionally, for example, the following method has been used. FIG. 6 is a diagram showing a conventional encryption method, and FIG. 6A shows a conventional encryption method.
(B) has shown the change of each information when a part of encrypted information is changed.

In the figure, is the information to be encrypted,
Is a random number sequence generated by a processor or the like, and is encrypted information. In FIG. 5A, in order to encrypt the information to be encrypted, four pieces of encrypted data A
1, A2, A3, A4 are added with random number sequences R1, R2, R3, R4 generated by a processor or the like. As a result, four ciphers D1, D2, D as shown in FIG.
3, D4 is generated.

In the above encryption method, if a part of the encrypted information (for example, A2 is changed to a2) is changed,
In the encrypted information (FIG. 6), the portion corresponding to the changed portion is changed, and the encrypted information is obtained as shown in FIG.

[0008]

By the way, in the encryption system shown in FIG. 6, when a part of the information to be encrypted (FIG. 6) is changed, as shown in FIG. The converted information (FIG. 6) is also changed in the portion corresponding to the changed portion. In the encryption of computer information, it is often the case that the encrypted information is reverse-encrypted, the encrypted information is partially changed, and then encrypted again. When a part of is changed, if the corresponding part of the information after encryption changes, the changed part is easily found and the cipher is easily deciphered.

The present invention has been made in order to improve the above-mentioned drawbacks of the prior art, and even if a part of encrypted information is changed, the changed portion is not easily found. The purpose is to provide a method of conversion.

[0010]

FIG. 1 shows the principle of the present invention. In the figure, 1 is means for generating additional information for generating additional information related to all the data from a data string of encrypted information, 2 is encrypted information, and 3 is generated additional information. 4 is a processing means for processing each data of the encrypted information to which the additional information is added by using the data before or after the respective data, and 5 is the processing means 4. A new data sequence generated by the above, 6 is a means for generating a random number sequence, 7 is a means for encrypting by adding a random number sequence to the data sequence 5, and 8 is generated encryption information. .

In order to solve the above problems, the present invention, as shown in FIG. 1, encrypts data and transmits it.
In the computer data encryption method in the inter-computer communication that keeps the data confidential, the additional information 3 related to all the data is generated from the data string of the information 1 to be encrypted. Then, the additional information 3 is added to the data string of the information 1 to be encrypted, and each data of the information 1 and 3 to be encrypted including the above-mentioned added information is used before or after the respective data. A new data string 5 is generated by processing the data string, and a process such as adding a random number sequence to the generated data string 5 is performed to generate an encrypted data string 8. ..

[0012]

In the present invention, the additional information 3 related to all the data is generated from the data string of the information 1 to be encrypted, added to the information 1 to be encrypted, and the added information is included. The encrypted data string 8 is generated by processing each data of the information 1 and 3 to be encrypted by using the data before or after each data and generating the new data string 5. Therefore, even if a part of the encrypted data string is changed, the entire encrypted data string changes.

Therefore, even when a part of the encrypted data string is changed, it is difficult to find the changed part, and the confidentiality of information can be improved.

[0014]

FIG. 2 is a flow chart showing an embodiment of the present invention. An embodiment of the present invention will be described with reference to FIG. 2 in the case of encrypting four data. Given a data string A consisting of four data, as shown in the figure, in step S1, the first column forms an array of spaces. In step S2, the four data A1, A2,
A3 and A4 are added and the last two digits are put in the first column of the array to obtain the array shown in FIG. Note that mod is a function that returns the last two digits, that is, a function that returns the remainder divided by 100.

At step S3, A0 + A1, A1
+ A2, A2 + A3, A3 + A4 are calculated, and the last two digits of the calculation result are put into a1, a2, a3, and a4 to obtain the arrangement shown in FIG. In step S4, a random number is generated in the processor or the like to obtain an array of 5-digit random numbers. In step S5, the array and each column of the array are added to obtain the encrypted data shown in FIG.

FIG. 3 is a diagram showing a change in encrypted information when a part of encrypted information is changed, and FIG. 3A shows a case where four pieces of information are encrypted by the above method. ,
(B) shows the case where a part of the encrypted information is changed. In the figure, the encrypted information is indicated by A in the first column.
Information with 0 added, information obtained by processing the information of, a random number sequence, and encrypted information. Also,
In the figure, the data changed by changing a part of the information to be encrypted is indicated by diagonal lines.

Next, referring to FIG. 3, as shown in FIG. 3A, the four pieces of information A1 to A4 are converted into the following equations (1) to (4).
In the case where the second data A2 of the encrypted information is changed after the encrypted information D0 to D4 is obtained by encrypting by the method shown in FIG. This will be described with reference to b). A0 = mod (A1 + A2 + A3 + A4) (1) a1 = mod (A1 + A0) (2) a2 = mod (A2 + a1) (3) a3 = mod (A3 + a2) (4) a4 = mod (A4 + a3) (5) (mod2 is lower) (Function for returning digits) In the same figure (b), if the second data A2 of the information to be encrypted is changed to a2, the value of the first column A0 of Figure (a)
Will be different. Therefore, the data of
The data obtained by processing by the following equations (7) to (10) are as shown in the same figure. Note that a1, a3, a4
Is a value different from a1, a3, and a4 in FIG. 3A, and (a) 2 is a value different from a2 in FIG.

A0 = mod (A1 + a2 + A3 + A4) (6) a1 = mod (A1 + A0) (7) a2 = mod (a2 + a1) (8) a3 = mod (A3 + (a) 2) (9) a4 = mod (A4 + a3) 10) (mod0 is a function that returns the lower 2 digits) The data A0, a1 shown in the above generated
By adding the random number sequences R1 to R4 shown in to a4 to a4, the encrypted information d0 to d4 shown in FIG.

As is apparent from FIGS. 2 (a) and 2 (b),
When the second data A2 of the encrypted data A1, A2, A3, A4 is changed to a2 by encrypting using the method of this embodiment, the data D0 to D4 shown in FIG. Changes to d0 to d4 as shown in FIG. 7B, and the changed portion is not easily found unlike the conventional example.

FIG. 4 is a diagram showing an embodiment in which the method shown in FIG. 2 is applied to data having specific numerical values. In FIG. 4A, data consisting of four numbers is encrypted by the above method. FIG. 7B shows a case in which a part of the data consisting of four numbers is changed and encrypted, and this embodiment is similar to the above-mentioned embodiment, and the lower 2
The modal function using digits is used to obtain the data and processing information added to the first column of the four numbers.

In the figure, data "12", "34", "56", "7" consisting of the four numbers in FIG.
When "8" is encrypted by the above method, as shown in FIG. 7A, "67", "57", "89", "03",
"69" is obtained. Here, as shown in FIG. 7B, the data “12”, “3
The second number "3" out of "4", "56", and "78"
If "4" is changed to "33", 4 shown in (a) of FIG.
The number "80" added before each number changes to "79" as shown in (b) of FIG. Therefore, the data "92", "26", "82" shown in FIG.
The four numbers "60" are "91", "24", "80", and "58" as shown in (b) of FIG.

Therefore, the encrypted data shown in (b) of FIG.
It becomes "66", "56", "67", "01", "67", data different from the encrypted data shown in (a) of the figure is obtained, and it becomes difficult to find the changed portion. . In the above embodiment, the function "mod" is used to obtain the information A0 related to all the encrypted information and the information processed using the A0. However, the present invention is not limited to this. The present invention is not limited to the above embodiment,
Various other well-known functions can be used.

In the above embodiment, addition is used as the means for processing the information, but the processing means of the present invention is not limited to addition, and other processing means can be used.

[0024]

As is apparent from the above description,
In the present invention, from the data string of information to be encrypted,
Generate additional information related to all the data, add it to the information to be encrypted, and use each data of the information to be encrypted including the added information by using the data before or after each data. Since the encrypted data string is generated by processing and generating a new data string,
Even if a part of the encrypted information is changed, all the encrypted information is changed, and it is difficult to find the changed part.

Therefore, it is possible to make it difficult to decipher the encrypted information, improve the confidentiality of the encrypted information, and change the encrypted information safely. become.

[Brief description of drawings]

FIG. 1 is a principle block diagram of the present invention.

FIG. 2 is a flowchart of an embodiment of the present invention.

FIG. 3 is a diagram showing changes in data when a part of encrypted data is changed.

FIG. 4 is a diagram showing an example using specific numerical values.

FIG. 5 is a diagram showing a conceptual configuration of an inter-computer communication system.

FIG. 6 is a diagram showing a conventional encryption method.

[Explanation of symbols]

 1 information to be encrypted 2 means for generating additional information 4 processing means 6 means for generating a random number sequence 7 means for encryption 8 generated encryption information

Claims (1)

[Claims] 1. An encryption method for computer data in computer-to-computer communication for maintaining confidentiality of data by encrypting and transmitting the data, wherein a data string of information to be encrypted relates to all the data. Generate additional information to be added to the data string of the information to be encrypted, and use each data of the information to be encrypted including the above-mentioned added information by using the data before or after each data. A computer data encryption characterized by generating a new data string by processing, and adding a random number sequence to the generated data string to generate an encrypted data string. Method.