JPH0374862B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a secure synchronization system, and in particular to a secure communication network consisting of one master station and a plurality of slave stations operated under a tree-structured communication flow. The present invention relates to a secure synchronization method for achieving secure synchronization in secure communication between a master and a slave station implemented in a secure communication system having at least one.

[Prior art]

A secure communication system that has at least one secure communication network consisting of one master station and multiple slave stations and that performs secure communication using a tree-structured communication flow is particularly designed to A master station at a communication rank sends a message one after another in a tree configuration to multiple slave stations at a lower communication rank, and conversely, a response from a slave station at a lower communication rank to a master station at a higher communication rank is transmitted from the master station that issued the communication and transmission. It is a form of communication operation that is limited to stations only, and is widely used and well known in various communication fields.

FIG. 1 is a block diagram showing the basic structure of a secret communication network with a tree structure.

The master station M01 in the upper communication rank issues business commands and business activity instructions to multiple slave stations in the lower communication rank, all of the five slave stations S01 to S05 in the case of Fig. 1, by secret communication as necessary. It is possible to transmit information such as Any slave station that receives such transmitted information, for example, slave station S
05 is the main station M as a main station with a higher communication rank.
01, and performs the necessary response transmission etc., but on the other hand, it acts as a master station M02 of a higher communication rank to slave stations S11 to S15 of a lower communication rank than its own station.

Furthermore, slave station S11 also exists as master station M03 for slave stations S21 to S25, and the aforementioned master station M01 also exists as master station M0, which is in a higher communication rank.
For 0, it will take the position of a subordinate station. Note that the response from the slave station to the master station is made only to the master station that has sent the secret communication to itself as a higher-level communication station, as shown by the dotted arrow in Figure 1, and in this way, the tree-structured communication flow is ensured. Ru.

In the example of FIG. 1, communication is normally carried out in communication block areas a, b, c, etc. according to information encryption using random numbers determined under the same protocol.

In secret communication conducted under such a tree-structured communication flow, the communication start time is set between the master and slave stations in order to keep the communication confidential and prevent the information content from being leaked through interception by a third party. The most common method is to establish secure synchronization between the two parties by controlling their positions.

However, in the conventional secure synchronization method of this type, a large amount of start time position data is captured through the interception of start time position control that is executed every time the secure communication between the master station and the slave station that constitutes the secure communication system starts. This results in a hint for decryption, and also has the disadvantage that the synchronization pull-in time of the random number code used in encryption increases.

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned drawbacks, and to transmit communication start time position data from a master station to slave stations by specifying different random number time slots in a secure synchronization method in a secure communication system using a tree structure. At the same time as secret communication is started, synchronization monitoring data is sent, and the slave station responds to the master station with the confirmed synchronization established or non-established status based on this synchronization monitoring data, and secure synchronization is achieved between the master and slave stations. It is an object of the present invention to provide a secret synchronization method which can greatly improve the possibility of decoding by interception and significantly reduce synchronization pull-in time by providing a means for decoding codes by interception.

[Structure of the invention]

The method of the present invention secures a tree-structured communication flow using a secret communication network that is composed of one master station and a plurality of slave stations and sends communication information from the master station to a plurality of slave stations, or a hierarchical combination thereof. A secret synchronization method for synchronizing secret communications in a secret communication system in which a communication system is formed to perform secret communications, and all stations included in the communication system are encrypted with the same random number under the same protocol. The random number generation speed in this case is the basic data speed N of the information to be communicated.
(NM and M are the total number of stations in the same code area)
A communication information concealing means for concealing communication information as a double, and a communication information concealing means for concealing communication information from a station acting as a master station to a station acting as a slave station in the same cryptographic zone are configured to conceal communication information at mutually different bit positions of the bit string based on the same random number. A random number bit is assigned to each slave station, and after transmitting synchronization initial data for secret communication, synchronization monitoring data for monitoring the synchronization state is transmitted, and transmission from the master station to a desired slave station on the tree structure is performed at the bit position. A master station transmitting means performs concealment using random number bits, and a slave station in a tree configuration designated as a recipient of the secure communication via this master station transmitting means transmits its own reception based on the synchronization monitoring data. While monitoring the synchronization state in operation and sending synchronization establishment or synchronization non-establishment data to the master station in the tree configuration depending on whether synchronization is established or not, it ensures synchronization in secret communication between the master station and slave station. The slave station synchronization ensuring means is also provided.

〔Example〕

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

FIG. 2 is a block diagram showing one embodiment of the present invention.

The embodiment shown in FIG. 2 is a secure communication system in which a master station 1 and P slave stations 2-1 to 2 have a hierarchically connected configuration to ensure a tree-configured communication flow.
-P is shown as an example, and the state in which a lower slave station is connected to the slave station is also shown using slave station 2-1 as an example. In this embodiment, in order to simplify the explanation, a master station 1 that exists as the highest level station and slave stations 2-1 to 2-P that exist under this master station 1 form the same cryptographic area. However, the composition size of the same cryptographic zone can be set arbitrarily depending on the operational purpose.

Now, slave stations 2-1 to 2-P receive confidential communications from master station 1, which has a higher communication rank, but master station 1
It is equipped with a MODEM (MOdulator-DEModulator) 11, a concealment circuit 12, etc., and attempts to conceal basic data to be sent to the slave stations 2-1 to 2-P in the following manner.

The operation of the embodiment will be described below using the master station 1 and slave station 2-1 as examples.

The main station 1 receives input signals input via a telephone, etc.
The data is encoded by a CODEC (COder DECoder) (not shown) or the like and then supplied to the MODEM 11 via an input line 111 as a basic data code.

MODEM 11 inputs the basic data code input via input line 111 and outputs it to output line 1.
12 to the anonymization circuit 12. The concealing circuit 12 transforms the information data by digitally adding the PN code output from the built-in PN (Pseudo Noise) code generator and the basic data code received via the output line 112. The information is kept confidential through code modulation using the PN code and the PN code.

The PN code generator used in this concealment combines an n-stage shift register and a logic circuit that feeds back the output state to the input side to generate pseudo-random numbers using the longest code of 2 ⁿ -1 bits, a so-called m-sequence code. The PN code generation rate is N times the basic data rate. Here, NM is the total number of master stations and slave stations set as the same code area, and in FIG. 2, it is the sum of master station 1 and slave stations 2-1 to 2-P. The above-mentioned pseudo-random numbers utilize binary random numbers "1" or "0" generated at random number time slots as subdivision times corresponding to bit positions in a random number bit stream that are set differently for each slave station. The randomized information data that has been anonymized is supplied to the MODEM 11. The randomized information data thus supplied to the MODEM 11 is P pieces of information scrambled with random numbers of P random number time slots set corresponding to P slave stations 2-1 to 2-P. In this case, when the random number "1" is specified, the information bit stream is inverted between "1" and "0", and when the random number "0" is specified, the information bit stream remains as it was. The MOD-EM 11 incorporates P MODEMs corresponding to the P slave stations to which randomized information data is to be sent, and these MODEMs use the randomized information data that inputs the carrier wave through the output line 121 to generate a predetermined signal. The signal is modulated according to the modulation format and sent to slave stations 2-1 to 2-P, etc.

FIG. 3 is a diagram showing an example of data sent from the main station in FIG. 2. Figure 3 shows an example in which communication information is sent out in chronological order via P communication paths to each slave station, and concealment is performed using random numbers specified by different random number time slots for each slave station. In the initial stage of synchronization, the anonymized information data D1 to DP are sent together with the bit position designation codes K1 to KP of the random number bit stream necessary for deciphering, and are sent from the master station to the slave station only at the start time of sending the confidential data. Data S and one piece of synchronous monitoring data P, which is output from time to time, are sent out. Among these various data, the synchronization initial data S and the synchronization monitoring data P require a significantly smaller number of bits to be allocated compared to the required number of bits for the concealed information data D1 to DP.

The above-mentioned time slot refers to a time period in which 1 bit of basic data is divided according to the number of slave stations.
Each of the slave stations 2-1 to 2-P receives concealed necessary information from the master station 1 using the random number bits in any of the time slots. The time slots for the slave stations 2-1 to 2-P are designated by the master station 1, and the concealed data transmitted through these time slots is converted into a PN code having a generation rate N times the basic data rate. Therefore, since the data is sent out in a sign-transformed state, it is possible to send out faithful basic data through concealment using random number bits designated by this time slot.

Prior to communication with slave stations 2-1 to 2-P, the master station 1 also sends data notifying the time position of the start of communication to all slave stations as confidential synchronization initial data, and then sends data to all slave stations to specify Messages are sent anonymously using time slots,
This content is received by the slave. Note that synchronization monitoring data is always sent from the master station to the slave stations to monitor the synchronization status, and each slave station has a function to monitor its own reception synchronization status based on this synchronization monitoring data. Synchronization establishment/non-establishment data indicating whether or not the received synchronization state of the terminal itself is established or not is sent to the main station 1, and this operation is repeated between each other until synchronization establishment is ensured.

The master station 1 and the slave stations 2-1 to 2-P all have random number generation mechanisms of the same configuration. The same configuration means that in addition to the identity of the constituent circuits, the drive clocks for random number generation are also basically consistent, and generally the random numbers generated by the master and slave stations in the same code area are synchronized by themselves. It is secured with a significantly smaller bit allocation than the basic data, and therefore, in order to maintain secure synchronization, synchronization initial data S as secure communication start information and power interruption etc. are required as shown in Figure 3. It is only necessary to transmit the target synchronous monitoring data with an extremely small bit allocation compared to the communication information.

In this way, the information from master station 1 to slave station 2-1 is concealed using random number time slots specified for each slave station.
~2-2-Secret communication and synchronization maintenance can be ensured only by transmitting one initial secure synchronization data at the start of communication and subsequent synchronization monitoring data for each P, but this does not apply to a tree-structured secure communication network. It is clear that this is possible because it is a confidential communication aimed at.

Now, slave stations 2-1 to 2-P, for example slave station 2-1
is a slave station to the master station 1, and can also behave almost in the same way as the master station 1 to the lower slave station group 3 including Q slave stations.

In the slave station 2-1, the synchronization circuit 21 is connected to the master station 1.
MODEM11 to output line 113 and
A time slot is specified by a synchronization signal specifying a random number time slot received via MODEM 26, and synchronization with the main station is maintained while receiving start time position data and synchronization monitoring data, and synchronization is established or not established. Accordingly, data indicating whether synchronization is established or not established is sent to the master station 1 via the output line 211, and until synchronization is not established, it continues to send synchronization non-establishment data to request synchronization, and the master station 1 sends synchronization requests to the slave station. The synchronization monitoring data continues to be sent until receiving a response from 2-1 that synchronization has been established.

When the slave station 2-1 acts as a master station, when the input signal 2001 from a telephone or the like is received by the CODEC 22, it is encoded based on a predetermined code format and then sent to the anonymizing circuit 2 via the switching circuit 23.
4, and thereby the number of slave stations to which commands or instruction messages are to be sent, in almost the same way as the anonymization process of the master station 1 described above, to the lower slave station group 3 in the embodiment shown in FIG. The Q included random number time slots are set based on mutually different bit positions, and the random number bits at these bit positions are used to convert into a concealed signal. MODEM(1)25-1～
MODEM (Q) 25-Q corresponds to the Q slave stations of the lower station group 3, and performs modulation/demodulation processing in the transmission and reception of secret communication performed with the slave station 2-1 as the main and the lower slave station 3 as the slave, and The signals sent and received from the station 1 are also modulated, and these operations are switched by a switching circuit 23.

Each MODEM achieves concealment and synchronization using the start time position data and synchronization monitoring data received from the concealment circuit 24 via the switching circuit 23, and the input signal is supplied concealed with the random number bits of the specified random number time slot. 2001 modulates the carrier wave in a predetermined format, and each of the Q slave stations included in the lower slave station group 3 receives signals from the slave station 2-1 using one of the Q designated random number time slots. The transmitted signal thus sent out is demodulated and the original signal is reproduced from the concealed data. Also, slave station 2
-1 also indicates the signals responded via MODEEM, etc. of Q slave stations in lower slave station group 3.
25-1 to 25-Q, and as described above, the main station 1, slave stations 2-1 to 2-P, and lower slave station group 3
A tree-structured secret communication is developed between each other, and in this case, secret synchronization is only performed when a master station in a higher communication rank attempts to perform secret communication with a slave station in a lower communication rank. Since it is no longer necessary to perform the process individually for each communication to multiple slave stations, the risk of giving clues to the decryption performed by intercepting the start time and position data can be greatly reduced. The time required to pull in the synchronization signal can also be significantly reduced.

In addition, in the above-mentioned secure communication, there is a secure communication network constituted by the master station 1 and slave stations 2-1 to 2-P, and another network constituted by the slave station 2-1 and lower slave station group 3. Each of the secret communication networks belongs to a different cryptographic district, and therefore the cryptographic rules, that is, the random number codes to be applied, are set to be different from each other to ensure confidentiality.

The present invention provides a secret communication network with a tree structure in which the same cryptographic protocol, that is, the same random number code, is used in the same cryptographic area consisting of one master station and multiple slave stations, and the N of basic data to be communicated is assumed to be the same. (NM; M is the total number of master stations and slave stations) Generates a random number code with twice the data rate, performs code conversion on the basic data using this random number code, and sends it out, ensuring confidentiality while synchronizing the data. The basic feature is that communication is carried out,
Various variations of the invention shown in FIG. 2 are possible. For example, in the embodiment shown in FIG. 2, master station 1 and slave station 2-1
Although the explanation is given by taking as an example a secret communication network constituted by a group of subordinate subordinate stations 3, the invention can be implemented in the same manner regardless of the structure and size of the secret communication network as long as it has a tree structure. It is clear that this is possible.

Furthermore, in the embodiment shown in FIG. 2, a PN code is used as the random number code generated by the concealing circuit 12 or 24, but it is clear that this can be implemented in the same way by using other composite code sequences. All of the above can be easily implemented without jeopardizing the gist of the present invention.

〔Effect of the invention〕

As explained above, according to the present invention, there is provided a secure synchronization method in a secure communication system configured using at least one of a secure communication network configured on a tree by a master station and a plurality of slave stations. N (N
M; M is the sum of the total number of master stations and slave stations)) A random number is generated at a data rate that is set as a common cryptographic protocol, and the data is anonymized according to this cryptographic protocol and sent from the master station to the slave stations. , and at this time, the master station and the slave station are provided with means for transmitting and receiving initial data to notify the start of secure communication, transmitting synchronization monitoring data, and corresponding synchronization establishment/non-establishment data response, and synchronization in secure communication. By achieving this, it is possible to realize a secure synchronization method that can significantly reduce the risk of decryption in secure communication and also significantly reduce the synchronization pull-in time of the random number code used for secure encryption.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the basic configuration of a secure communication network with a tree configuration, FIG. 2 is a block diagram showing an embodiment of the secure synchronization method according to the present invention, and FIG. FIG. 3 is a diagram showing an example of sequential time-series transmission from a main station. 1...Main station, 2-1 to 2-P...Slave station, 3...Lower slave station group, 11...MODEM, 12...Secretization circuit, 21...Synchronization circuit, 22...CODEC, 2
3...Switching circuit, 24...Secretization circuit, 25-1
~25-Q...MODEM(1)~MODEM(Q), 2
6...MODEM.

Claims (1)

[Claims] 1. Formation of a communication system that secures a tree-structured communication flow through a secret communication network consisting of one master station and multiple slave stations and transmitting communication information from the master station to multiple slave stations, or through hierarchical combination thereof. A secret synchronization method for synchronizing secret communications in a secret communication system in which secret communications are carried out using the same code, in which all stations included in the communication system perform encryption using the same random number under the same protocol. A communication information concealing means that configures a ward and in this case, the random number generation speed is multiplied by the basic data rate of information to be communicated N (NM, M is the total number of stations in the same cryptographic ward) to conceal communication information. The communication information from the station acting as the master station to the station acting as the slave station in the same code area is concealed by assigning random number bits at different bit positions of the same random number bit string to each slave station, and concealing the communication information. master station transmitting means for transmitting synchronization initial data and then transmitting synchronization monitoring data for monitoring the synchronization state while transmitting from the master station to a desired slave station in the tree configuration by concealing the bit position using random number bits; and whether synchronization is established while the slave station in the tree configuration designated as the recipient of the secret communication via this master station transmission means monitors the synchronization state of its own station's reception operation based on the synchronization monitoring data. A slave station synchronization ensuring means is provided for ensuring synchronization in secret communication between the master station and the slave station while transmitting synchronization establishment or synchronization non-establishment data to the master station on the tree structure in response to whether or not the synchronization is established or not. A secret synchronization method.