JPH01269975A - Simple type data ciphering system - Google Patents

Abstract

PURPOSE:To force a third person to erroneously recognize information as live information by subjecting the random components generated by adding check bits of CRC to information bits to a cyclic shift on a transmission side and generating random numbers and subjecting the reception data of the random number components to a reverse cyclic shift. CONSTITUTION:The CRC (Cyclic Redundancy Check Code) check bits are first added to the transmission data by a means 1 and the random numbers are obtd. by a means 2 for generating the random numbers on the data transmission side at the time of ciphering the data added with the CRC. The random number components and code words obtd. by a means 3 are cyclically shifted and are transmitted to a communication path. The same random numbers as the random numbers on the transmission side are obtd. by the means 4 and the random components obtd. by the means 5 are subjected to the reverse cyclic shift and the decoding of the CRC is executed by a means 6 to obtain reception data 12 on the data reception side. The third person is thereby forced to judge the data on the communication path as the correct data which is not ciphered.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to data encryption.

The following margin [Conventional technology] In the conventional encryption method, #CRC (Cyclic R
(edundancy check code) Data to which check bits have been added is encrypted using a random method (method unrelated to the mechanism for adding CRC check bits, such as the DES method).

[Problem to be solved by the invention]

In conventional encryption methods, when encrypting data with a CRC added, the encrypted data is

Since the data is no longer encoded based on CRC, if a third party intercepts the data and decodes it based on CRC rules, it will naturally be determined that there is an error. . This type of event occurs with most data.

A third party may be able to determine that the data is encrypted. If a third party can be made to believe that the intercepted data is not encrypted, the time it takes to decrypt it can be extended. Therefore, a technical problem of the present invention is to provide a simple data encryption method that can make a third party think that intercepted data is not encrypted.

[Means to solve the problem]

According to the present invention, CRC (Clyclic Red
When encrypting data with undancyCheck Code) added, on the sending side, CR is added to the information pit.
A means for encrypting by adding 9 check pits of C and applying cyclic shift to a random number generated by 9, and a means for encrypting by generating a random number on the receiving side, cyclically shifts the received data (with the same random number as).

A simplified data encryption method having means for performing CRC decoding is obtained.

〔Example〕

An embodiment of the present invention will be described with reference to one drawing.

FIG. 1 is a diagram showing a configuration diagram of the present invention.

The data transmitting side first adds CRC check bits to the transmitted data using means 1 for adding CRC check pits. Next, a random number is obtained by means 2 for generating a random number. In means 2, it is necessary to keep the random number generation mechanism and the initial value for generating the random numbers secret between the transmitter and the receiver. That is, this random number may be used as the encryption key for each data unit, and the random number may be different for each data unit.

Then, by means 2 and 3, the code word is cyclically shifted by the obtained random number. This is sent to one communication channel. Not yet stored in memory.

On the data receiving side, the procedure is performed in the reverse order of the procedure on the sending side. First, by means 2 and 4, the same random number as that on the sending side is obtained. then 1
A reverse cyclic shift is performed by the random number obtained by means 5. Then, CRC decoding is performed on the inversely cyclically shifted data by the second means 6 to obtain received data 12.

〔Effect of the invention〕

As described above, according to the present invention, an unauthorized third party determines that data on a communication path is unencrypted data. Therefore, an unjustified third party may obtain incorrect information. This is because the data on the second communication path is encrypted.

And the CRC check code is correct.

If an unauthorized third party decodes the CRC, it can be decoded correctly (it is determined that there are no errors). Therefore, an unjustified third party will judge that the information is correct.

Therefore, true information is not easily leaked to unauthorized third parties. Furthermore, since the encryption/decryption mechanism is only a cyclic shift, it has the advantage of being relatively simple.

The invention is particularly effective when the data is binary. This is because both encrypted and unencrypted data are in binary format, so an unauthorized third party can access the information before and after the data.

This is because it becomes difficult to determine whether the intercepted data is encrypted or not.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an encryption system implementing the present invention. 1: A means of adding a CRC check pit. 2: means for generating random numbers; 3: means for cyclically shifting the code word by the obtained random number; 4: means for generating the same random number as on the sending side; 5: means for inversely shifting the code word by the obtained random number. means for click-shifting; 6: means for decoding CRC;
11: Transmission data, 12: Reception data.

Claims (1)

[Claims] 1) When encrypting data to which a CRC has been added, the transmitting side adds a CRC check bit to the information bits,
A means for performing encryption by performing a cyclic shift by the generated random number, and a means for generating a random number, reversely cyclically shifting the received data by the random number, and performing CRC decoding on the receiving side. A simple data encryption method featuring: