JPS62225043A - Informarion transfer system - Google Patents

Abstract

PURPOSE:To prevent leakage of secrecy by preparingplural number of generation polynomials not opened in public or data to both communication equipments and sending information while adding designation information of an operation value to them to a sent data. CONSTITUTION:Four kinds of not opened generation polynomials A,B,C and D are registered in areas correspnding to four pcsof polynomial designation information (CE) in a main memory MM of each terminal equipment. Further, a prescribed bit number of addresses taking 2-bit CE as a low-order bit are assigned to each area and non-public generation polynomials A D and their CEs used for the information transfer between both terminal equipments are decided between users by a proper method. Then the designation information of the operation value to the generation polynomial or data to be used is added to a sent data to transfer the information. Thus, even when the 3rd party receives a modified data and teh CE, since the generation polynimials are not opened to public, the data is not restored into the data before modification and the leakage of secrecy is prevented effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an information transfer method applied to an information communication system, and particularly to an information transfer method added with a security function.

Conventional technology In digital information communication systems, CRC (Cy
clic Redundancy Check) method is adopted.

For example, CCITT No. 7 i! In the case of the 11-wire signaling system, the level 2 signal former converts a data field (S I F) transformed by a predetermined generator polynomial and a CRC code field (C
K).

Problems to be Solved by the Invention In the above-mentioned CCITT No. 7 common channel signaling system, the generating polynomial is fixed, so there is a risk of leakage of confidentiality due to crosstalk due to characteristic deterioration or failure of the transmission path within the network. be.

Structure of the Invention The information transfer method of the present invention that solves the problems of the prior art described above prepares a plurality of types of calculation values for generating polynomials or data that are not disclosed to both communication devices, and transfers the generating polynomials or It is configured to prevent leakage of confidential information by adding designation information of a calculation value for data to the transmitted data and transferring the information.

Hereinafter, the operation of the present invention will be explained in detail together with examples.

Embodiment FIG. 1 is a transmission/reception information signal form diagram of an information transfer system according to an embodiment of the present invention that conforms to the above-mentioned CCITT No. 7 common line signal method 2.

Each field at levels l and 2 of the lower hierarchy consists of an 8-bit start flag (SF), a 7-bit backward sequence number (I3SN), a backward indicator bit (BIB), and a 7-bit forward sequence number (FSN). , a forward indicator bit (FIB), a 6-bit signal length indicator field (Ll,
), 2-bit generator polynomial specification information (CF, ), 8
A CRC code (check byte) of n (n≧2) 16 bits and an end flag (EF) of bits are sequentially sent to the transmission path.

At levels 3 and 4 of the upper hierarchy, only data (SIF) is handled.

As shown in FIG. 2, in the main memory (MM) of each terminal device, there are four types of undisclosed generator polynomials A, B, C and It has an area for registering D. Each area is assigned an address of a predetermined number of bits, with 2 bits of generator polynomial designation information (CE) as the lower 2 bits. The private generating polynomials A to CE used for information transfer between the two terminal devices and their designation information (CE) are agreed upon in advance by these users in an appropriate manner.

At level 4 of each terminal device, a generating polynomial to be used for information transfer is specified by a key input from the user. At the upper level of each terminal device, deformed data (S I F) is deformed using the generator polynomial specified by the user.
A CRC code (CK) is created and passed to the lower level, and generator polynomial designation information (CE) to be added is notified to the lower level. In addition, at the lower level of each terminal device, the modified data (SIF) received from the other party and the CRC code (CK
) to the higher level, and also notifies the higher level of the generator polynomial designation information (GE) received from the other party. The upper level restores the data before transformation and detects errors based on this information.

Therefore, a third party receives the deformed data and the generator polynomial designation information (again, since the generator polynomial is not disclosed, it cannot be restored to the data before deformation, and confidentiality is maintained).

Since four types of generating polynomials are prepared, they can be changed each time information is transferred, or fixedly assigned to four groups of transfer partners.

In addition, in order to save the user the trouble of specifying the generator polynomial, the generator polynomial specification information is cyclically incremented each time one information transfer or one packet is sent, and the generated random number is divided by 4. It is also possible to configure an automatic specification in which the quotient obtained by the calculation is used as the generator polynomial specification information.

By changing the generator polynomial regularly or irregularly, confidentiality can be maintained even more effectively.

The above example illustrates a configuration that uses multiple types of generator polynomials, but
Instead of fixing the generator polynomial, multiple types of undisclosed calculation values are registered in memory, and one calculation value selected by the sending side is used to perform calculations on the data before and after transformation by the generator polynomial, and the receiving side In this case, a configuration may be adopted in which the private calculation value specified based on the calculation value designation information corresponding to the CE is read out and the inverse calculation is performed.

Furthermore, although the present invention has been exemplified in the case of a common line signaling system conforming to CCITT No. 7, the present invention can also be applied to other information transfer systems that employ error detection using the CRC method.

Effects of the Invention As explained in detail above, the information transfer method of the present invention has the following effects:
Both communication devices have a configuration in which multiple types of undisclosed generating polynomials or calculated values for data are prepared, and information is transferred by adding designation information of the generating polynomial to be used or calculated values for data to the transmitted data. Therefore, even if a third party receives the deformed data and generator polynomial designation information, the generator polynomial is hidden and cannot be restored to the data before transformation, effectively preventing leakage of confidential information. This effect is achieved.

[Brief explanation of drawings]

Figure 1 is a format diagram of transfer information in an embodiment of the present invention that is compatible with the common channel signaling system of CCITT No. 7, and Figure 2 is a diagram of the generating polynomial stored in the main memory (MM) of both terminal devices. Fig. 3 is a conceptual diagram showing the correspondence between CCITT No. 7 and its designated information.
FIG. 3 is a format diagram of transfer information in the 11-line signaling system. CB...Generating polynomial specification information, SIF...Deformation data,
CK...CI? C code, MF14...Main memory.

Claims (2)

[Claims] (1) Prepare multiple calculation values for generating polynomials or data that are not disclosed to both communication devices, and transfer information by adding designation information of the calculation values for the generator polynomials or data to be used between the two to the transmitted data. An information transfer method characterized by: (2) The information transfer method is CCITT NO. 7, the information communication system conforms to the common channel signaling system of No. 7, wherein the information specifying the calculation value for the generating polynomial or data is transferred using a 2-bit free area of level 2 transfer information. An information transfer method according to claim 1.