RU2249857C2 - Method for encoding/decoding - Google Patents

Abstract

FIELD: electric communications.

SUBSTANCE: method is performed using microcontrollers with two memory types: data and software. For transfer of each symbol individual main and reserve codes are used, on basis of number of repeats of symbol in transferred message. First transfer of symbol is performed by main code, second transfer of same symbol - by reserve code, and then codes synchronization displacement is activated for a step around circle relatively to symbols until finish of circle. After transfer of displaced reserve code, closing the circle, synchronous replacement of codes variants is performed, and then order of codes replacement is repeated in case of repeat of any symbol in transferred message. Number of required code variants is set by planned volume of information, sent via communication line.

EFFECT: higher efficiency.

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Description

The invention relates to the field of telecommunications and can be used as a method of encoding-decoding to protect information when transmitting it over a communication line.

Known encoding-decoding methods use the same code to transmit an information symbol, regardless of the number of repetitions in the transmitted message. This affects the security of the communication channel and makes it possible to decrypt the transmitted message by non-addressees.

Currently, information protection in communication networks is mainly provided by the applied methods of effective coding, see, for example, M.G. Arkhipov, K.A. Kuzmishko, S.M. Arkhipov. “Theoretical Foundations of the Safe Protection of Stationary Protected Facilities,” ed. “The Grail House”, Moscow, 2002, pp. 100 ... 115. The use of effective codes ensures the practical reliability of information protection at the maximum transfer rate. However, the issue with the transmission of characters repeated in the message has not been resolved. They will be transmitted with the same codes. This affects the security of the transmitted information in the communication network from unauthorized access.

Of the known encoding-decoding methods, the closest analogue can be recognized as the method by which the “Electronic Locking Device” is built, see Patent No. 2180386 for Application No. 2001100885, priority dated January 9, 2001, which is selected as a prototype.

The prototype contains transceivers and microcontrollers having two types of memory: data and software. The data memory contains the same for the lock and key record codes, individual for each unlock. The program memory contains a record of commands executed during unlocking or locking. The data memory contains n cells. Each cell contains a different code for each unlocking of the lock. In one of the data memory cells is the current unlock code, which, when subsequently locked, randomly switches to another cell. The program memory contains a sequence of commands that are used to unlock and lock the lock. These commands for the key and the lock are different and are started automatically after pressing the keys of the key “OPEN” or “CLOSE”.

The prototype works as follows. When working between the key and the lock, two-way communication occurs. In this case, to unlock the key, the key requests the number of the cell in which the unlock code is recorded. Upon request of the key, the lock transfers this number to the key. In accordance with the accepted number, the key receives the unlock code from its data memory and transfers it to the lock. After receiving the unlock code, the lock is unlocked.

When locking a lock, the unlock code automatically changes randomly to a new one, which is recorded in another lock memory.

In its original form, the prototype cannot be used as an encoding-decoding device, however, based on the prototype, such a device can be created.

The aim of the invention is the creation of an encoding-decoding device that improves the quality of protection of information transmitted over the communication line from being intercepted by non-addressees by converting the transmitted message into a repetitive code.

This goal is achieved by the fact that in the encoding-decoding device microcontrollers have two types of memory: data and software. Symbols are stored in the data memory, for example letters, numbers, signs, and their corresponding individual codes for transmitting symbols over a communication line. Commands are entered in the program memory by which characters are replaced by codes in the encoding and codes by characters in the decoding device. Each character in the data memory is made with a permanent address. Codes used to transmit any character are made with a variable address. Due to this, any retransmission of the symbol in the transmitted message has a new code. Several code options are involved. In each variant, each symbol has its own individual primary and backup code.

The code of the transmitted character is determined by the program memory command based on the number of its repetitions in the transmitted message. The first transmission of the character is done by the main code. The second transmission of the same symbol is made by the backup code. Then, in the encoding-decoding device, a synchronous shift of the codes by a step in a circle with respect to the symbols is activated. The second third transmission of the character is performed by the shifted main code. The fourth symbol retransmission is performed by the shifted backup code. Then the synchronous shift of codes to the next step is involved. This is repeated until the end of the circle. After the transfer of the biased backup code that closes the circle, a synchronous change of code options is performed in the encoding / decoding device. Then the order of the change of codes when repeating any character in the transmitted message is repeated. The number of required code options is set by the planned amount of information transmitted over the communication line, equipped with this sample encoding-decoding device.

The drawing shows a structural diagram of the inventive device. In this scheme, the transmitted signal is connected to the encoding device 1. This signal is fed to the input of the program memory node 2. The node 2 has two-way communication with the data memory node 3. The output signal of the encoding device 1 is the codes that are removed from the output of the node 2.

The received code signal is connected to the decoding device 4. This signal is fed to the input of the program memory node 5. The node 5 has two-way communication with the data memory node 6. The output signal of the decoding device 4 is the symbols that are removed from the output of the node 5.

The claimed device operates as follows. Depending on the number of repetitions of the same characters in the transmitted message, the claimed device works either with the main code, or with the backup code, or with the replacement of the variant codes.

Consider these modes of operation of the device.

1. The operation of the device with the main code.

The encoder 1 operates on the following commands of program memory 2:

1. Reception of the character.

2. Transmission of a character to a data memory address.

3. Request the main character code from the data memory.

4. Getting the main character code from the data memory.

5. Transmission of the main character code to the output of the encoder 1.

The decoding device 4 operates on the following commands of program memory 5:

1. Reception of the main code.

2. Transfer of the main code to the data memory address.

3. Request a character from the data memory.

4. Getting a character from data memory.

5. Transmission of the symbol to the output of the decoding device 4.

2. The device operates with a backup code.

The encoder 1 operates on the following commands of program memory 2:

1. Repeated reception of the same symbol.

2. Transmission of a character to a data memory address.

3. Request a backup character code from the data memory.

4. Obtaining a backup character code from data memory.

5. Transfer the backup character code to the output of the encoder 1.

6. In the data memory, relative to the characters, the offset of the individual codes by a step in a circle.

The decoding device 4 operates on the following commands of program memory 5:

1. Reception of the backup code.

2. Transfer of the backup code to the data memory address.

3. Request a character from the data memory.

4. Getting a character from data memory.

5. Transmission of the symbol to the output of the decoding device 4.

6. In the data memory, relative to the characters, the offset of the individual codes by a step in a circle.

3. The operation of the device with the replacement of the variant codes.

The encoder 1 operates on the following commands of program memory 2:

1. Repeated reception of the same symbol, which refers to the last step of the circle.

2. Transmission of a character to a data memory address.

3. Request a backup character code from the data memory.

4. Obtaining a backup character code from data memory.

5. Transfer the backup character code to the output of the encoder 1.

6. In the data memory, a change of code options.

The decoding device 4 operates on the following commands of program memory 5:

1. Reception of the backup code of the last step of the circle.

2. Transfer the backup code of the last step of the circle to the data memory address.

3. Request a character from the data memory.

4. Getting a character from data memory.

5. Transmission of the symbol to the output of the decoding device 4.

6. In the data memory, a change of code options.

If it is necessary to expand the communication network, the new subscriber, before joining the communication, requests from any of the subscribers working in the communication network the code currently used to transmit the first character. Having received it, the new subscriber sets in the data memory the original individual codes of all the characters based on the code of the first character. These codes coincide with the source codes at a given moment in time for subscribers working in the network. Then the new subscriber communicates in the usual manner.

The communication line, which includes the inventive device, provides communication with codes that do not have repetition.

This quality is achieved in that each retransmission of any symbol in the transmitted message is carried out by a new code.

Due to this, decryption of the transmitted message by the non-addresser is excluded when it intercepts a communication session.

Claims (1)

A coding-decoding method that protects information when it is transmitted over the communication line from being intercepted by non-recipients, performed using microcontrollers that have two types of memory: data and software, characterized in that characters are stored in the data memory, for example, letters, numbers, characters and their corresponding individual codes for transmitting characters over a communication line, instructions are entered into the program memory by which characters are replaced by codes in the coding and codes by characters in the decoding device, each The nth character in the data memory is executed with a constant address, and the codes used to transmit any character are executed with a variable address, due to which any retransmission of a character in the transmitted message has a new code, and several codes are used in which each character corresponds to individual primary and backup codes, the code of the transmitted symbol being determined by the program memory command based on the number of its repetitions in the transmitted message, while the first transmission of the symbol is performed by the main one, the second with a backup code, then in the encoding / decoding device a synchronous shift of the codes is activated by a step in a circle with respect to the symbols, the second third transmission of the symbol is carried out by the shifted main code, the fourth repeated transmission of the symbol is performed by the shifted backup code, then the synchronous shift of the codes by the next step, and so on, is repeated until the end of the circle, and after transmitting the shifted backup code that closes the circle, a synchronous change of code variants is performed in the encoding / decoding device, and then the order of the change of codes when repeating any character in the transmitted message is repeated, while the number of required codes is set by the planned amount of information transmitted over the communication line, equipped with this sample encoding-decoding device.