JPH01297928A - Secret multi-address communication system - Google Patents

Abstract

PURPOSE:To make a secret communication with plural specific nodes by sending enciphered data together with an added singular bit string and deciphering it only by the specific nodes in the multi-address communication of a local area network. CONSTITUTION:When a transmission control circuit 11 sends out the enciphered data 11a to the specific nodes capable of the secret communication, a sent data enciphering circuit 13 sends out the data 12a through a transmitting buffer 12. The circuit 13 adds the singular bit string to the head of the enciphered data and passes the data 12a to a transmission frame control circuit 14. The circuit 14 adds a header, etc., to constitute a multi-address data frame, which is sent to a transmission line. When other specific nodes receive the enciphered data, a reception frame retrieval circuit 8 detects the singular bit string and a deciphering circuit 9 deciphers the received data 8a and stores it on a receiving buffer 10. Other nodes have neither the circuits 8 nor 9 and can not decipher the cipher therefore, only the specific nodes can perform the secret communication.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a secure broadcast communication system using a local area network and using encryption.

[Conventional technology]

Conventionally, confidential broadcast communication in a local area network has been performed by transmitting a data frame with a special pattern set in the destination address. Furthermore, no method has been thought of to date that allows confidential communications to be sent to specific nodes by using encryption in broadcast communications.

[Problem to be solved by the invention]

In the conventional confidential broadcast communication mentioned above, the information is decrypted by all nodes, and in encrypted communication, confidential information can only be sent to one node at the same time. The disadvantage is that information cannot be transmitted.

[Means to solve the problem]

The secure broadcast communication method of the present invention includes a transmission control circuit that requests the transmission of encrypted data that can only be decrypted by a specific node during broadcast communication in a local area network, and a transmission buffer that outputs the transmission data in response to the request to transmit the encrypted data. a transmission data encryption circuit that encrypts the transmission data by adding a bit string for cryptographic identification according to the transmission request; a transmission frame control circuit that adds a header to the transmission data to configure a data frame; a received frame search circuit that outputs an activation signal when detecting the bit string from a data frame received from the data frame; and a decryption circuit that decodes and outputs the received data using the activation signal;
It has a receive buffer that holds received data.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a connection diagram of each node for explaining the embodiment. This will be explained with reference to FIGS. 1 and 2.

In FIG. 2, nodes A1 to G7 are connected to a transmission line to form a local area network. Here, it is assumed that node A1, node E5, and node F6 can communicate with each other using encrypted data.

Figure 1 shows node A1, node E5, and node F in Figure 2.
6 is shown.

In node A1, when there is a transmission request 11b for encrypted data lla from transmission control circuit 11, transmission buffer 12 sends transmission data 12a to transmission data encryption circuit 13. The transmission data encryption circuit 13 encrypts the transmission data 12a, adds a unique sequence of 1 to 1 at the beginning of the data to identify that it is encrypted data, and passes it to the transmission frame control circuit 14. The transmission frame control circuit 14 adds a header and the like to form a broadcast data frame, and sends it onto the transmission path.

Node E5. Upon receiving the encrypted data, the node F6 detects a unique bit string in the received frame search circuit 8, and
An activation signal 8b is output to the decryption circuit 9. The decryption circuit 9 decrypts the received data 8a in response to the activation signal 8b and loads the result into the reception buffer 10.

On the other hand, node B2, node C3, node D4, and node G7 determine that this encrypted data is just a broadcast frame, and load it into the reception buffer 10. However, since the encryption cannot be deciphered, the meaning of this data is unknown.

〔Effect of the invention〕

As explained above, the present invention has a circuit that adds a unique bit string to the beginning of encrypted data so that the receiving node can identify the encrypted data. This has the effect of allowing confidential communications to be carried out.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a connection diagram of each node for explaining the embodiment. 1-7... Nodes A-G, 8... Reception frame search circuit, 9... Decryption circuit, 10... Reception buffer, 11... Transmission control circuit, 12... Transmission buffer,
13... Transmission data encryption circuit, 14... Transmission frame control circuit.

Claims (1)

[Claims] a transmission control circuit that requests the transmission of encrypted data that can only be decrypted by a specific node during broadcast communication in a local area network; a transmission buffer that outputs the transmission data in response to the transmission request of the encrypted data; and a transmission buffer that outputs the transmission data in accordance with the transmission request. A transmission data encryption circuit that adds and encrypts a bit string for cryptographic identification, a transmission frame control circuit that adds a header to transmission data to configure a data frame, and detects the bit string from a data frame received from another node. A secure broadcast communication system comprising: a received frame search circuit that outputs an activation signal when the activation signal is activated; a decryption circuit that decodes and outputs received data in response to the activation signal; and a reception buffer that holds the received data.