JPH0414337A - Cryptographic communication system - Google Patents

Abstract

PURPOSE:To prevent decoding of information when reception information is separated by sending multiplexed information with cryptographic processing and decoding plural sets of information from which the reception information is demultiplexed. CONSTITUTION:Plural sets of information M1-Mn are multiplexed by a multiplexer circuit 103 and ciphered by a cryptographic device 104 and the result is sent via a transmission circuit 105. Then the information is received by a reception circuit 106, demultiplexed into plural sets of cryptographic information by a demultiplexer circuit 107 and decoded by plural decoders 108 corresponding to each demultiplexed information. Since the information is not decoded when the reception information is demultiplexed, intercept and decoding of the information are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cryptographic communication system, and more particularly to a cryptographic communication system with an improved method for decoding a code.

[Conventional technology]

A block diagram of an example of a conventional cryptographic communication system is shown in FIG. In FIG. 5, information M, 501 to information M, .
A multiplexing circuit 503 multiplexes n pieces of information up to 502, an encoder 504 encrypts the multiplexed information, and a transmitting circuit 505 transmits the encrypted information.

This transmitted information is received by a receiving circuit 506, this received information is decoded by a decoder 507, this decoded information is separated by a separation circuit 508, and information M, 509 to information M, , 510 are separated. Output n pieces of information.

[Problem B that the invention seeks to solve].

Since the above-mentioned conventional technology first decrypts the received encrypted multiplexed information and then separates the information, there is a problem in that the information can be decoded by eavesdropping at the time of decryption.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a decoding communication system with an improved method for decoding encrypted multiplexed information.

[Means for Solving the Problems] In order to achieve the above object, the encrypted communication system of the present invention first converts received encrypted multiplexed information into single information using a demultiplexing circuit, and then decrypts and outputs it. This is how it was done.

[Effect]

In the above cryptographic communication system, the received encrypted multiple information is still encrypted at the time it is converted into single information, so
It becomes impossible for a third party to decipher the information, and it also becomes impossible for one legitimate recipient to decipher a single piece of information about another person.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 1 is a block diagram showing an embodiment of a cryptographic communication system according to the present invention. In FIG. 1, 107 is a separation circuit, 108 is a decoder, 209t is information M, 21
0 is information M, .

FIG. 2 is a flow diagram showing the processing procedure of FIG. 1. Second
In the figure, step 210 is information M, 101 of FIG.
The circuit 1 multiplexes n pieces of information from M to information M, , 102.
Step 03 multiplexes the information, Step 102 encrypts the multiplexed information with the encoder 104, Step 103 transmits the encrypted information, Step 104 receives the transmitted information with the receiving circuit 106, and Step 105 receives the received information. The information is separated by the separation circuit 107, and in step 106, the separated pieces of information are decoded by the decoder 108, and the information M and 109 are decoded. Outputs n pieces of information up to 110.

FIG. 3 is a block diagram showing another embodiment of the cryptographic communication system according to the present invention. In FIG. 3, 301 is information M, 302 is information M2, 303 is a multiplexing circuit, 304
is an encoder, 305 is a transmitting circuit, 306 is a receiving circuit, 30
7 is a separation circuit, 308 is a decoder, and 309 is a decoder.

, 310 is information M, and 311 is information Mn.

FIG. 4 is a flow diagram showing the processing procedure of FIG. 3. Fourth
In the figure, step 401 is information M, 301 in FIG.
The circuit 3 multiplexes n pieces of information from M to information M, 302.
Step 402 encrypts the multiplexed information with the encoder 304, Step 403 transmits the encrypted information with the transmitting circuit, Step 404 receives the transmitted information with the receiving circuit 306, and Step 405 The separation circuit 307 separates the received information into n pieces of single information, and in step 406, each of the separated n pieces of single information is sent to a decoder, 3.
Decoder from 08. The data is decoded by each of n decoders up to 309, and n pieces of information from information M and 301 to information M and 311 are output.

According to the above embodiment, when the received encrypted multiple information is converted into single information, it is impossible for a third party to decrypt the information, and one of the legitimate recipients can It is also impossible to decipher any information.

〔Effect of the invention〕

According to the present invention, there is an effect that the received encrypted multiple information is not decrypted once it is converted into single information by the demultiplexing circuit.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a flowchart of the processing procedure of FIG. 1, FIG. 3 is a block diagram showing another embodiment of the present invention, and FIG. FIG. 5 is a block diagram showing a conventional example. 101.103...Information M,,102,302...
Information Mゎ, 103,303... Multiplexing circuit, 104゜304... Encryptor, 105,305... Transmitting circuit,
106.306...reception circuit, 107,307...
Separation circuit, 108...Decoder 2, 308...Decoder 1.309...Decoderゎ, 109,310...Information M110.311...Information M11゜Patent applicant Hitachi Shonan Representative of Denshi Co., Ltd. Patent attorney Tadashi Akimoto 1 person outside the company Figure ■Σ■ Figure Figure Figure

Claims (1)

[Claims] 1. means for multiplexing a plurality of pieces of information, means for encrypting the multiplexed information, and means for transmitting the encrypted information;
A cryptographic communication system comprising means for receiving transmitted information, means for separating the received information, and means for decoding the separated plural pieces of information. 2. The encrypted communication system according to claim 1, wherein the means for decoding the plurality of pieces of information comprises the same number of decoders as the plurality of pieces of information.