JPH01181349A - Multiple address communication system - Google Patents

Abstract

PURPOSE:To obtain an economical multiple address communication system where the content of communication is not leaked to a 3rd party and there is no reception time difference between terminal equipments enabling the confirmation of transmission by combining an individual connection type transmission line and a broadcast type transmission line. CONSTITUTION:Two transmission lines of individual connection type transmission line 12 and broadcast type transmission line 13 are provided from an information output device 1 to a reception terminal equipment 3. Then the transmission of a cryptographic key for decoding and the communication of transmittal confirmation are applied through the individual connection type transmission line 12 and the multiple address information is sent through the broadcast type transmission line 13. Thus, there is no care about the leakage of the content of communication to the 3rd party and the transmission is confirmed and the inexpensive multiple address communication system is obtained, where there is no reception time difference between terminal equipments.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to data communication, and more particularly to a broadcast communication system using a wireless transmission path or a wired transmission path having a multiple connection function.

[Conventional technology]

FIG. 2 is a block diagram of individually connected transmission paths of a conventional broadcast communication system. In the figure, 1 is an information output device, 2
is an individually connected transmission path, and 3 is a receiving terminal.

Conventionally, in a broadcast communication system that transmits the same information to multiple specific subscribers, (1) After connecting the receiving terminal 3 and the information output device 1 one-to-one through the individually connected transmission path 2 such as a wire, , performs information transmission processing, and sequentially receives these operations at the destination;

Broadcast communication was achieved by repeating this process as many times as there were terminals.

(2) Broadcast communications were realized using broadcast transmission channels such as radio.

[Problem to be solved by the invention]

This method (11) has the following drawbacks.

■Since sequential line connection and transmission processing are required for each destination terminal, there is a time difference in receiving information between terminals.

In order to reduce the zero time difference, it is necessary to increase the number of lines between the information output device 1 and a switching device inserted in the middle of the transmission path, and further improve the processing capacity of the information output device 1.

■This makes the system expensive.

On the other hand, in method (2), the above-mentioned problem disappears, but ■
Receiving terminal 3 cannot be identified. ■The communication direction is one-way, and it is not possible to confirm whether or not the communication content has correctly arrived at the receiving terminal side (delivery confirmation).

■Communication contents are leaked to a third party.

Problems such as this occur.

[Means to solve the problem]

The present invention provides two transmission paths, an individual connection type transmission path and a broadcast type transmission path, from an information output device to a receiving terminal, and uses the individual connection type transmission path to transmit an encryption key for decryption and to communicate delivery confirmation. The broadcast information was transmitted through a broadcast transmission channel.

〔Example〕

(l)) Figure 1 is a block diagram of the system of the present invention;
The figure is a detailed block diagram of the invention.

1 is an information output device, 3 is a receiving terminal, 4 is information, 5 is a destination, 6 is a transmission confirmation means, 7 is an encryption key generation means, 8 is an encryption means, 9 is an error correction code addition means, and 10 is a broadcast type transmission path transmitting means; 11 is individually connected transmission path transmitting and receiving means; 12;
13 is an individual connection type transmission path, 13 is a broadcast type transmission path, 14 is a broadcast request terminal, 15 is an individual connection type transmission path transmission/reception means, 20 is an individual connection type transmission path transmission/reception means, 23 is a broadcast type transmission path transmission means, 24 represents an error correction means, and 25 represents an encryption/decryption means.

The processing information output device 1 generates an encryption key each time a communication request occurs by the encryption key generation means 7, and generates an encryption key each time a communication request occurs.
1, the subscriber number (hereinafter referred to as DN (Directory Number)) is sent to the destination 5 via the individually connected transmission path 12.
The encryption key is sequentially transmitted to each of the plurality of receiving terminals 3 designated in accordance with the following.

Generally, the data length of the encryption key can be made sufficiently smaller than the data length of the original information to be encrypted, so the time and processing load required for successive transmission of the encryption key are extremely small.

On the other hand, the information output device 1 uses the encryption key in the encryption means 8 to encrypt the original information of the broadcast request received from the broadcast request terminal using the encryption key, and the error correction code addition means 9 corrects the error. After adding a code to form encrypted information, the broadcasting transmission path transmitting means 10 broadcasts it all at once to an unspecified number of receiving terminals 3 via the broadcasting transmission path 13.

The receiving terminal 3 receives this encrypted information, corrects the transmission error during transmission by the error correcting means 24, and decrypts the encrypted information using the previously separately received encryption key.
Decrypt by

■Broadcast request processing The broadcast request terminal 14 that makes the broadcast request uses the individually connected transmission path transmitting/receiving means 15 to send the transmission destination consisting of a plurality of DNs that are broadcast communication destinations and the original information to the individually connected transmission path. 12 to the information output device 1.

■Reception confirmation processing When the receiving terminal 3 confirms that the error correction has been performed normally, the individual connection type transmission path transmitting/receiving means 20 transmits the reception confirmation signal with the own DN added thereto through the individual connection type transmission path 12. The information is sent back to the information output device 1.

■The broadcast communication status processing information output device 1 receives this reception confirmation signal, and compares the DN added to the reception confirmation signal with the DN of the broadcast destination by the delivery confirmation means 6 to determine the broadcast communication status. Calculate. That is, delivery can be confirmed from the DN of the reception confirmation signal,
Nondelivery can be confirmed from a DN that is not included in the DN of the reception confirmation signal that is included in the DN of the broadcast destination. As a result, the information output device 1 reports the broadcast communication status to the broadcast request terminal 14 through the individually connected transmission path transmitting/receiving means 11, and the broadcast request terminal 14 receives the broadcast communication status.

As explained above, according to the present invention, the broadcast type transmission path 1
Since the information is transmitted all at once using the terminals 3, it is cheaper than using the individually connected transmission paths 12, and it is possible to realize broadcast communication with no difference in information reception time between the receiving terminals 3.

The encrypted information broadcast on the broadcast transmission channel 13 can be received by receiving terminals other than the broadcast destination, but since it is encrypted, there is no fear that the communication contents will be leaked to a third party. Furthermore, since the reception confirmation signal can be sent back to the information output device 1 using the individually connected transmission path 12, delivery confirmation can be made.

In this way, a system can be constructed in which two transmission paths, the individually connected transmission path 12 and the broadcast transmission path 13, are combined in the receiving terminal 3 to take advantage of the strengths of each.

(2)) FIG. 4 is a system block diagram of one embodiment of the present invention, in which a communication control unit 39 having a multiple connection mechanism (hereinafter abbreviated as multipath mechanism) using a time division multiplex switch is shown.
This is an example in which a corresponding digital exchange device 31 is used as a transmission path. In the figure, 31 is a digital switching device (multipath connection mechanism), 32 is a CPU, 33 is a terminal request reception processing section, 34 is a random number generation section, 35 is an encryption processing section, 36 is a storage section, 38 is a RAM, 39 is a communication control unit, 40 is an error correction code processing unit, 41 is a reception confirmation signal processing unit, and 42 is an RO.
It is M. The digital exchange device 31 has a multipath connection mechanism compatible with l5DN, and the communication control unit 39 has -ISDN.
This is a basic interface (2B+D) communication control unit that controls transmission and reception of two multiplexed Bch lines and one Dch packet. Each block in FIG. 4 shows that the configuration blocks of the information output device 1, the broadcast request terminal 14, and the receiving terminal 3 have substantially the same configuration as a computer. Individual connection type transmission path 12 and broadcast type transmission path 13 in FIG.
In this embodiment, the digital switching device 31 has a multipath connection mechanism, and the individual connection type transmission path 12 uses Dch packets, and the broadcast type transmission path 13 uses Bch packets. Each corresponds to a transmission path using a multipath connection mechanism. First, a multipath connection mechanism in which three terminal lines are multiplexed on one data highway will be described. The operating principle is the same even if the multiplicity is 3 or more.

FIG. 5 is an explanatory diagram of the principle of multipath connection in the digital switching device 31. In the figure, 51 is a time slot memory, 52 is a read control memory, 53 is a clock, 54 is an input data highway, and 55 is an output data highway. First, an overview of the digital exchange operation by the time slot memory 51 will be explained. Digital signals input from multiple terminal lines are divided into data of a fixed length called time slots, and are transferred to the input data highway 5.
4, the signals are multiplexed and transmitted as time slots corresponding one-to-one to each terminal line. Similarly, the signals on each time slot that are multiplexed and carried on the output data highway 55 are distributed and transmitted to the corresponding terminal lines. A, B, and C are terminal line #1, terminal line #2, and
It represents a signal on a time slot that is input from terminal line #3, multiplexed on the data highway, and transferred.

The clock 53 is for supplying timing for writing data into the time slot memory 51 in units of time slots and timing for reading data from the read control memory 52. The time slot memory 51 sequentially writes time slots input from the input data highway 54 into the time slot memory 51. On the other hand, the read control memory 52 is a memory for storing the order in which time slots written in the time slot memory 51 are read. By changing the contents of the read control memory 52, it becomes possible to read the time slots in an order different from the order written in the time slot memory 51 and send them to the output data highway 55, thereby making it possible to read out the time slots in an order different from the order written in the time slot memory 51 and send them to the output data highway 55. 55, the order of time slots is changed and signals can be exchanged between terminal lines.

Next, a multipath connection mechanism using the digital switching device 31 described above will be explained. In FIG. 5, if the contents of the read control memory 52 are all set to 2, for example, all B will be read out onto the output data highway 55, and B will be sent to all terminal lines.
A multipath connection mechanism can be realized. The signal input from terminal line #2 is transferred from time slot memory 51 to #1, #
The time difference between transmissions to each terminal line #2 and #3 is less than the time required to transmit one time slot on the terminal line. A time slot, which is a unit of exchange processing in a normal digital exchange device 31, is only a few bits long, which is much smaller than the length of the entire information to be broadcast. The broadcast time difference can be virtually ignored, and it is considered to have the same function as a broadcast transmission channel.

Next, the operation of this embodiment will be explained.

0 processing FIG. 6 is a flowchart outlining the operation of the embodiment.

Prior to broadcast transmission, the read control memory 52 of the digital switching device 31 is configured so that all the receiving end bundles 3 that may be selected in various broadcast communication requests and the information output device 1 can be connected in a multipath manner. The contents are set in advance using the method described above. That is, when the Bch line of the receiving terminal 3 is in an empty state due to the multipath connection mechanism,
The Bch line is connected to the Bch line of the information output device 1. As a result, the information output device 1 and the digital exchange device 31
The connection process between the receiver terminal 3 specified by the DN and the receiver terminal 3 specified by the DN is not performed every time a broadcast call occurs; It becomes possible to send it to the terminal 3. Therefore, compared to conventional broadcast communication systems that use one-to-one connections sequentially or using multiple lines, the processing load for connection and information transmission is significantly reduced. Since only one line is required, the system is much more economical. This effect is more noticeable when the number of broadcast destinations is large.

When a broadcast communication request occurs in such a situation, the information output device 1 first generates a random number and uses it as an encryption key. This encryption key is sent to the receiving terminal 3 specified by the broadcast destination 5
h packets are sent sequentially. Receiving terminal 3 receives the encryption key and blocks Bch so that other terminals do not use it.

The information output device 1 encrypts the original information to be transmitted using the encryption key, adds an error correction code to form encrypted information, and
The data is sent to the digital exchange device 31 via channel. The digital switching device is a multipath connection mechanism, and uses the Bch to send the information received from the information output device 1 to unspecified receiving terminals regardless of the broadcast destination. The receiving terminal 3 performs error correction on the encrypted information received on Bch, and decrypts it using the encryption key received using the method described above.

■Broadcast request processing First, the broadcast request terminal 14 sends information requesting broadcast transmission and the broadcast destination to the information output device 1 using a Dch packet. The information output device 1 receives the transmission information and the broadcast destination from the broadcast request terminal 14. The subsequent operations are as described above.

■Receipt confirmation processing When the receiving terminal 3 has correctly corrected the error, the Dch
A reception confirmation signal is sent back to the information output device 1 using a packet. Since a caller identification number is automatically added to the Dch packet, the DN of the receiving terminal 3 is added to the reception confirmation signal. The DN of the information output device 1 used by the receiving terminal 3 when returning the reception confirmation signal may be the caller identification number added to the input Dch packet when receiving the encryption key. After receiving the signal, it is possible to know which receiving terminals 3 were able to communicate correctly from the DN added to the reception confirmation signal, and by comparing it with the broadcast destination, it is possible to know which receiving terminals 3 were not able to communicate correctly.

■The broadcast communication status processing information output device 1 transmits the broadcast communication status, which is a list of the DNs of the receiving terminals 3 that were able to communicate correctly and the DNs of the receiving terminals 3 that could not communicate correctly, to the broadcast requesting terminal using a Dch packet. Send on 14th.

〔Effect of the invention〕

According to the present invention, by combining an individual connection type transmission path and a broadcast type transmission path, communication contents can be prevented from being leaked to a third party.
It is possible to provide an economical broadcast communication system in which delivery confirmation is possible and there is no difference in reception time between terminals.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the system of the present invention, FIG. 2 is a block diagram of individually connected transmission paths of a conventional broadcast communication system,
Fig. 3 is a detailed block diagram of the present invention, Fig. 4 is a system block diagram of one embodiment of the invention, Fig. 5 is an explanatory diagram of the principle of multipath connection of digital switching equipment, and Fig. 6 is an implementation example. 2 is a flowchart outlining an example operation. 1 is an information output device, 2 is an individual connection type transmission line, 3 is a receiving terminal, 4 is information, 5 is a destination, 6 is a delivery confirmation means, 7 is an encryption key generation means, 8 is an encryption means, and 9 is an error correction 10 is a broadcast type transmission path transmitting means; 11 is an individually connected type transmission path transmitting/receiving means; 12 is an individually connected type transmission path; 13 is a broadcast type transmission path; 14 is a broadcast request terminal; 15 is an individually connected type transmission path. transmission path transmitting and receiving means; 20 is individually connected transmission path transmitting and receiving means;
23 is a broadcast type transmission path transmitting means, 24 is an error correction means, 2
5 is an encryption/decryption means, 31 is a digital exchange device, 32
is a CPU, 33 is a terminal request reception processing section, 34 is a random number generation section, 34 is an encryption processing section, 36 is a storage section, and 38 is a RAM
, 39 is a communication control unit, 40 is an error correction code processing unit, 41
42 is a ROM, 51 is a time slot memory, 52 is a read control memory, 53 is a clock, 54 is an input data highway, 55 is an output data highway, and DN is a subscriber number. Patent applicant Nippon Telegraph and Telephone Corporation agent Patent attorney Tama Mushi Kugobe (2 others) 3rdrlA = Ko1!

Claims (4)

[Claims] (1) A means for generating an encryption key each time a communication request occurs and delivering the encryption key to the subscriber corresponding to the subscriber number via an individual connection type transmission path, and encrypting information with the encryption key and making errors. an information output device having means for adding a correction code to form encrypted information and broadcasting the same to receiving terminals all at once via a broadcast type transmission path; The encryption key received by
A broadcast communication system comprising the receiving terminal that decodes the encrypted information and the original information received via the broadcast transmission path. (2) means for delivering broadcast destinations consisting of a plurality of subscriber numbers and source information used for broadcast from the broadcast request terminal to the information output device via the individual connection type transmission path; A broadcast communication system according to claim 1, characterized in that: (3) When the error correction code is successfully corrected, the receiving terminal sends a reception confirmation signal to notify that it has correctly received the own subscriber number via the individually connected transmission path. 2. The broadcast communication system according to claim 1, further comprising means for sending the information back to the information output device. (4) Receiving a broadcast communication request from a broadcast requesting terminal and transmitting a broadcast communication status report consisting of a list of subscriber numbers returned from the receiving terminal to the information output device through the individually connected transmission channel. 2. The broadcast communication system according to claim 1, further comprising means for transmitting the information to the broadcast requesting terminal via.