JPS6145646A - Ciphering system - Google Patents

Abstract

PURPOSE:To prevent interception of data communication in an on-line system by using a key table including a character ciphering element comprising operating information and an operator at each character of a text. CONSTITUTION:A text to be ciphered is stored in a register 1. A ciphering element at each character in response to a character position in the text is stored in a register 2 for the length of maximum text (key table). A ciphered text is stored in a register 3. A character position designating register 4 designates the character ciphering element corresponding to each character location of the register 2 and each character location of the registers 1 and 3. One character designated by the register 4 amount texts stored in the register 1 is stored in a register 5. Operating information of the character ciphering element designated by the register 4 is stored in a register 6 among the ciphered elements in the key table stored in the register 2. The ciphered character is stored in a register 10.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an information encryption method used for data communication between a terminal device and a central processing unit.

(Prior art #) An online system in which a terminal device and a central processing unit are connected via a communication line is used in financial institutions such as banks, seat reservations in national railways and airlines, air transport pipes 18, defense organizations, etc.
It has come to be used in a variety of ways, including production control in factories.

Recently, as portable portable terminal devices have begun to be adopted as components of online systems, communication lines are no longer limited to conventional specific communication lines, but public communication (general subscriber telephone) lines are increasingly being used.

On the other hand, as technology and equipment for monitoring these communication lines have developed, social problems have arisen due to wiretapping of communication lines in financial institution systems, for example.

(Problems to be Solved by the Invention) For this reason, it has been considered to encrypt the information to be sent to the communication line and decrypt it to its original form on the receiving side. Conventionally, a method was adopted in which a modified ThL UaH device with a scrambling function or an encryption device was attached externally, but with this method, the terminal device itself and the modem or external device were vulnerable to eavesdropping between the encryption device. There was a drawback.

Furthermore, when encrypting something as simple as, for example, converting the number 60'' to the alphabet ``A'', there is a drawback that it is easy to decipher by eavesdropping.

Therefore, an object of the present invention is to provide an information unit (
The object of the present invention is to realize an encryption method that is difficult to decipher by performing a different encryption operation on each character position fit -78 of the text (hereinafter referred to as text).

Another object of the present invention is to realize an encryption method that is difficult to eavesdrop on by implementing an encryption operation by internal operation of a terminal device.

(Means for Solving the Problems) According to the present invention, for each character of a text to be transmitted, calculation information for encryption and an operator are linked corresponding to each character position in the text. The C1 table has a C1 table large enough to accommodate the maximum length of the text to be transmitted containing the character encryption element as content, and scans the text to be transmitted character by character, and determines the position of each character. The present invention will now be described in detail with reference to the drawings showing an embodiment of the present invention.

In FIG. 1, register 1 stores the text to be encrypted. The register 2 stores encrypted elements for each character corresponding to the character position within the text for the maximum text length (hereinafter referred to as a key table). Register 3 stores encrypted text. Character position designation register 4 designates a character encryption element corresponding to each character position in registers 1 and 3 and each character position of text in register 2. One character specified in register 4 from among the text stored in register 1 is stored in register 5. The register 6 stores calculation information for the character encryption element designated by the register 4 among the encryption elements in the key table stored in the register 2. register 7
Similarly, operators for character encryption elements are stored in . The arithmetic controller 9 controls the arithmetic unit 8 according to the contents of the register 7.

One encrypted character is stored in register 1o.

Next, the encryption process will be explained.

First, when the text to be transmitted is stored in register 1, register 3 is cleared and character position designation register 4 is reset to zero. Next, increase the contents of register 4 by 1, transfer one character in register l specified by the contents to register 5, and transfer the character encryption element in register 2 specified by the contents of register 4 to the operation The information is taken out to register 6 and the operator is taken out to register 7.

Arithmetic unit 8 performs an operation specified by the contents of register 7 on the contents stored in registers 5 and 6 under the control of arithmetic controller 9, and stores the result in register 10. One character of the encrypted text temporarily stored in register 1o is stored in the position specified by register 4 of register 3. When one character in the register is thus encrypted and stored in register 3, the contents of register 4 become 1.
The next character from register 5 is incremented by
Then move on to the action of taking it out. When all the intersections of the text to be encrypted in the register have been encrypted, the information before and after the encrypted text includes the beginning of the text, the station number of the sending source, the end of the text, etc. A control code indicating this is added and sent to the destination.

In the encryption calculation, it is necessary to select the calculation information and the operator so that the characters in the text are not converted into control codes for transmission control by being encoded. Furthermore, when decoding is performed on the receiving side, it is necessary to select calculation information and operators that will not cause the original text information to be lost.

The text encrypted in this manner can be decrypted on the receiving side by performing an inverse operation using the same key table as on the sending side.

(Effects of the Invention) As explained above, the present invention enables an online system to encrypt text using a key table that includes a character encryption element consisting of calculation information and an operator for each character of text. It becomes possible to prevent data communication information from being intercepted.

[Brief explanation of the drawing]

The drawing is a block diagram showing one embodiment of the present invention. 1...Text register, 2...Key table register, 3...Encrypted text register, 4...Character position register, 5, 10
...1 character register, 6... i-report register for calculation, 7... register for operator, 8.
...Arithmetic unit, 9...Arithmetic controller. Agent: Susumu Uchihara, patent attorney.

Claims (1)

[Claims] For each character of the text to be transmitted, a character encryption element consisting of a pair of calculation information and an operator for encryption corresponding to each character position in the text is added to the maximum of the text to be transmitted. scan the text to be transmitted character by character, and for each character position, scan the text to be transmitted one character in accordance with the corresponding character encryption element of the key table; An encryption method characterized by encrypting each time.