KR100275495B1 - Key transmission apparatus using modem and its method - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a key transmission apparatus using a modem and a method thereof.

2. The problem to be solved by the invention

SUMMARY OF THE INVENTION An object of the present invention is to provide a key transmission apparatus and a method for allowing a communication terminal to transmit a key without using a computer network by transmitting a required public key using a dial-up modem of a PSTN.

3. Summary of Solution to Invention

The present invention provides a storage means for storing a key; Control command input means for inputting a control command; Connecting means for connecting signals; Means for generating and receiving double tone multi-frequency signals; Modulation and demodulation means for modulating and demodulating the transmitted key; Control means for controlling the connection means and the demodulation means, for transmitting the key stored in the storage means to the demodulation means according to a control command, and for controlling the dual tone multi-frequency signal generation and reception means; And matching means for matching keys transmitted and received between the personal computer and the control means.

4. Important uses of the invention

The present invention is used to transmit a public key required for a communication terminal on a PSTN.

Description

Key transmission device using modem and its method

The present invention relates to a key transmission device used in a public switched telephone network (PSTN), and in particular, dial-up of a public key required for applying a public key cryptosystem to a communication terminal on the PSTN. The present invention relates to a key transmission device for transmitting by using a modem.

In general, public key cryptosystems are used in computer network environments, and the key can be transmitted according to the data access processing method operating in the network.However, the importance of protecting personal and group secrets has emerged. The public key cryptosystem has also been introduced for various communication terminals.

In the public key cryptosystem, a separate key (for example, a public key and a private key) is used for encryption / decryption, and a public key must be obtained through a public channel.

In addition, in order to apply such a public key cryptographic system to a communication terminal of a PSTN, a data transmission apparatus for transmitting a public key is required.

For this purpose, a computer equipped with a modem can be used as a data transmission device in the PSTN, but in this case, a computer is required for each terminal, which is too expensive and still requires an additional connection procedure for key transmission. Thus, there was a very inefficient problem in terms of economic and practical.

Accordingly, the present invention has been made to solve the above problems, and by transmitting a public key required for applying a public key cryptosystem to a communication terminal on the PSTN using a dial-up modem of the PSTN, the communication terminal is a computer. It is an object of the present invention to provide a key transmission device and a method for transmitting a key without using a network.

1 is a block diagram of a PSTN network to which the present invention is applied.

Figure 2 is a block diagram of an embodiment of a key transmission apparatus using a modem according to the present invention.

Figure 3 is an embodiment procedure for the connection process between the key transmission device and the PC of the present invention off-line.

Figure 4 is an embodiment procedure for the connection process between the receiving side and the transmitting side key transmission apparatus according to the present invention on-line.

5 is a flow diagram of an embodiment of a key connection process of the microprocessor of FIG.

Explanation of symbols on the main parts of the drawings

210: memory 220: keypad

230: line interface circuit 240: microprocessor

250: dual tone multi-frequency signal generation and reception unit 260: modem

270: driver 280: display unit

According to an aspect of the present invention, there is provided a key transmission apparatus for transmitting a key, comprising: storage means for storing a key transmitted from a personal computer; Control command input means for inputting a control command for controlling the key transmission device; Connection means for connecting signals transmitted and received between the electronic switch and the terminal and the key transmission device; A dual-tone multi-frequency signal for receiving and transmitting a dual-tone multi-frequency signal transmitted from the electronic switch through the connection means, and providing a dual-tone multi-frequency signal to the terminal through the connection means under the control of the control means. Generating and receiving means; Modulation and demodulation means for modulating the key transmitted from the control means and transmitting the modulated key to the connection means, and demodulating the key transmitted from the connection means to the control means; Store the key transmitted from the personal computer in the storage means, and control the connection means and the demodulation means while transferring the key stored in the storage means to the demodulation means according to a control command input through the control command input means. And control means for receiving the dual tone multi-frequency signal from the dual tone multi-frequency signal generating and receiving means and controlling the dual tone multi-frequency signal generating and receiving means; And matching means for matching keys transmitted and received between the personal computer and the control means.

The present invention also provides a key transmission method for transmitting a key through a public switched telephone network (PSTN), comprising: a first step of performing key transmission and reception according to whether a memory is normal; A second step of receiving a key by being connected to a personal computer off-line; A third step of storing a key received from the personal computer in the memory; And a fourth step of transmitting a key stored in the memory on-line through a modem connection with a counterpart.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. 1 to 5.

1 is a configuration diagram of a PSTN network to which the present invention is applied, and includes a personal computer (PC) 110, key transmission devices 120, 130, and 140, a terminal 150, and a PSTN 160. It is composed of

Referring to the characteristics of the key transmission apparatus of the present invention through the PSTN network to which the present invention having the structure described above is applied is as follows.

The key transmission device 120 downloads the key from the PC 110 through the serial interface on the off-line and stores it. In the key transmission apparatus according to the present invention, the transmitting side and the receiving side are configured with the same equipment, but the transmission device 120 storing the key becomes the main device, and after the other party's key transmission device 130 makes a telephone call and accesses the key, The access procedure is configured to accept.

Therefore, the key transmission apparatus according to the present invention can make and receive telephone calls by itself, is connected by modem protocol after a telephone connection is established, and has a function of transmitting keys by modem control. It will automatically proceed.

When the key transmission device of the present invention is not used for key transmission / reception, the connection between the key transmission device 140 and the terminal 150 is provided without replacing a connector separately by providing an input / output terminal on a general telephone line. It is also a configuration that can use a regular phone. Therefore, the key transmission device according to the present invention has a function of switching a telephone line.

2 is a block diagram of an embodiment of a key transmission apparatus using a modem according to the present invention.

As shown in FIG. 2, the key transmission device of the present invention includes a memory 210 for storing a key transmitted from the PC 201 and a keypad 220 for inputting a control command for controlling the key transmission device. ), A circuit interface circuit 230 for connecting signals transmitted and received between the electronic switch 202 and the terminal 203 and the key transmission device, and a circuit interface circuit 230 from the electronic switch 202. Receives and transmits the transmitted dual tone multi-frequency signal (DTMF) and provides the dual tone multi-frequency signal to the terminal 203 through the line interface circuit 230 under the control of the microprocessor 240. Dual-tone multi-frequency signal generation and reception unit 250 and the key transmitted from the microprocessor 240 modulates the key transmitted to the line interface circuit 230, demodulates the key transmitted from the line interface circuit 230 The modem 260 and the key transmitted from the PC 201 to the processor 240 is stored in the memory 210 and stored in the memory 210 according to a control command input through the keypad 220. Control the line interface circuit 230 and the modem 260 while transmitting to the modem 260, receives the dual tone multi-frequency signal generation and reception of the double tone multi-frequency signal from the receiving unit 250 and generates a double tone multi-frequency signal and A microprocessor 240 for controlling the receiver 250 and a driver 270 for matching keys transmitted and received between the PC 201 and the microprocessor 240 are provided.

In addition, the present invention further includes a display unit 280 for displaying an internal state of the key transmission device transmitted from the microprocessor 240.

Referring to the operation of the key transmission device of the present invention having the structure described above in detail as follows.

The memory 210 stores externally input data and uses a nonvolatile memory because the contents of the stored data must be preserved even when the power is turned off. It is connected to the data and address bus (not shown) of the microprocessor 240, and checks the entire check_sum at the beginning of the operation of the key transmission device, and the result is displayed on the display unit 280.

The key transmission device may operate by itself, and in this case, a keypad 220 is required for the operation of the key transmission device. The keypad 220 is displayed with the numbers '0' to '9' and '*' and '#', and the keypad 220 serves as an electronic terminal button. Perform the functions required for your own test and operation. In addition, the keypad 220 is connected to the microprocessor 240 to transmit a control command input by the user to the microprocessor 240.

The circuit interface circuit 230 performs a function of connecting the signal transmitted from the modem 260 to the terminal 203. In addition, a call connection maintenance state from the terminal 203 is sensed, and a ring input is detected and reported to the microprocessor 240. In addition, the line interface circuit 230 adjusts the level of the dual tone multi-frequency signal transmitted from the electronic switch 202 and transmits the dual tone multi-frequency signal generation and reception unit 250 to generate the dual tone multi-frequency signal and The level of the dual tone multi-frequency signal transmitted from the receiver 250 is adjusted and transmitted to the terminal 203.

The microprocessor 240 drives the driver 270 to download the corresponding key data from the PC 201 and store it in the memory 210. The microprocessor 240 performs a function of the user through the keypad 220. Receives a control command and displays the state inside the key transmission device on the display unit 280, and analyzes the call connection information (for example, ring and call connection maintenance state) transmitted from the line interface circuit 230. The modem 260 is driven to perform modem 260 connection processing with the other party and to control data transmission and reception.

The driver 270 is connected through the serial input / output of the microprocessor 240, the keypad 220 and the display unit 280 are connected through the parallel input / output port of the microprocessor 240, and the modem 260 is a microcomputer. The processor 240 is connected via serial or parallel input / output.

In addition, the microprocessor 240 manages the memory 210 by giving a corresponding address, and the line interface circuit 230 and the dual tone multi-frequency signal generating and receiving unit 250 are microprocessors formed by parallel ports and interrupts. Connected to 240. In addition, the microprocessor 240 gives and manages an input / output address for each peripheral device, and allows the operation to proceed by an interrupt of each peripheral device for real time operation.

The dual sound multi-frequency signal generator 250 receives the dual sound multi-frequency signal transmitted from the electronic switch 202 through the circuit interface circuit 230 and transmits the multi-tone multi-frequency signal to the microprocessor 240. In this way, when receiving a dual-tone multi-frequency signal, the microprocessor 240 controls to generate a dual-tone multi-frequency signal by controlling the dual-tone multi-frequency signal generation and reception unit 250, accordingly, the dual-tone multi-frequency The signal generator and receiver 250 provides a dual tone multi-frequency signal to the terminal 203 through the line interface circuit 230 under the control of the microprocessor 240.

The modem 260 performs a function of extracting digital data from a signal transmitted from the line interface circuit 230. In particular, the modem 260 performs a modem connection protocol by performing a modem connection protocol during initial modem connection.

The modulation and demodulation speed of the modem 260 is generally applied according to the standard of the dial-up modem of the PSTN network. In addition, the modem 260 is connected to the microprocessor 240 via a parallel interface or a serial interface, and the analog input and output of the modem 260 is connected to the line interface circuit 230.

The driver 270 converts a signal coming from the serial interface of the microprocessor 240 into a signal standard suitable for the PC 201 and transmits it to the PC 201, and also transmits key data transmitted from the PC 201 to the microprocessor ( 240 converts it into a signal suitable for processing and passes it to microprocessor 240.

The display unit 280 is connected to the microprocessor 240 and performs a function of displaying the state of the key transmission device for the user to see. That is, the display unit 280 displays a storage state of a key in the memory 210, a user button input value, a line connection state, and whether the key value transmission is successfully completed.

As described above, the key transmission apparatus of the present invention has two operation functions, which can be classified as follows.

First, on off-line, the microprocessor 240 has a function of downloading a key from the PC 201 and storing it in the memory 210.

Second, on-line, the microprocessor 240 has a function of transmitting a key stored in the memory 210 to the modem 260 through a modem connection with the other party.

FIG. 3 is a flow chart of an embodiment of a connection process performed between a PC and a key transmission device when the key transmission device of the present invention is connected to a PC and downloaded a key off-line.

Referring to FIG. 3, when the PC 201 inquires the state of the key transmission apparatus by sending an access code Ack of an ASCII code (301), the key transmission apparatus checks an internal failure state and then fails. According to the test result, a connection permission signal or a connection not available signal is transmitted to the PC 201 (302).

Subsequently, the PC 201 transmits (303) the name (Code_name) of the key data file for downloading to the key transmission device, and the PC 201 transmits the number of data (Code_length) to download. (304) is transmitted to the key transmission device.

Subsequently, the PC 201 transmits actual data to the key transmission device as much as the number of data to download (305), and finally transmits a checksum to the key transmission device for checking whether or not the data has failed (306). ).

Subsequently, the key transmission apparatus checks the checksum of the data downloaded therein, and transmits a normal signal for the data or a fault signal for the data to the PC 201 according to the result (307).

Key data downloaded through the above process is stored in the memory 210.

FIG. 4 is a flow chart of an embodiment of a connection process between two key transmission apparatuses when key data stored in the memory of FIG. 2 is transmitted online through a modem connection with a counterpart.

Referring to Fig. 4, first, the key transmission device on the key receiving side which wants to receive key data is hooked off (401), and then dials the telephone number assigned to the key transmission device on the key transmitting side. In step 406, the PSTN rings the ring signal to the key transmission apparatus on the key transmission side (403). In this way, the key transmission device on the key transmission side that stores the key data is automatically hooked off after detecting the ringing (404).

Subsequently, when " DTMF D, D, D " indicating that the key transmitting device on the key transmitting side is the key transmitting side is transmitted to the key transmitting apparatus on the key receiving side (405), the key transmitting apparatus on the key receiving side transmits the received DTMF. It sends its identifier (ID) to the key transmitting apparatus on the key transmitting side (406).

In this way, if the transmitted user ID matches the key transmitting apparatus on the key transmitting side, the key transmitting side checks the user ID, and if correct, the V.8 of ITU-T between the key transmitting apparatus on the key receiving side and the key transmitting apparatus on the key receiving side. A modem connection procedure based on the protocol is performed (407).

When the modem connection procedure is completed, the key transmitting apparatus on the key receiving side transmits the key number to be transmitted to the key transmitting apparatus on the key transmitting side (408).

Subsequently, when the key transmitting apparatus on the key transmitting side transmits the actual key data corresponding to the key number transmitted from the key transmitting apparatus on the key receiving side to the key transmitting apparatus on the key receiving side (409), the key transmitting apparatus on the key receiving side After confirming whether or not the key data is correctly transmitted, the confirmation result is transmitted to the key transmission apparatus on the key transmission side.

The key transmission apparatus of the key receiving side which is to receive the key through the above-described process may receive the corresponding key data, but if a failure occurs in the key reception, the key transmission apparatus retransmits the requested key number to perform the transmission procedure. .

FIG. 5 is a flowchart illustrating a key connection process of the microprocessor of FIG. 2.

As shown in FIG. 5, after the initialization is performed, it is determined whether the memory 210 is normal (501), and if an error occurs in the memory 210, the microprocessor 240 stops the operation of the key transmission device. (502).

If the memory 210 is determined to be normal in the process 210 of determining whether the memory 210 is normal, it is checked whether normal key data is received from the PC 201 (503), and the abnormal state from the PC 201 is determined. If the key data is received, it is determined whether a ring signal is input (504), and if the ring signal is not input, the process proceeds to the suitability determination process (501) of the memory 210.

If it is determined in step 504 whether the ring signal is input or not, the ring signal is input, and after hooking off the key transmission apparatus of the key receiving side to receive the key data, The telephone number assigned to the key transmission device is dialed (505).

Subsequently, it is checked whether the DTMF indicating that the key is transmitted is received from the key transmission apparatus on the key transmission side (506). If not, the DTMF reception confirmation process is performed until the DTMF is received while maintaining the DTMF reception standby state. Repeat step 506).

If it is confirmed that the DTMF is received in the acknowledgment process 506 of the DTMF, the modem access procedure according to the V.8 protocol of the ITU-T is performed (507).

When the modem connection procedure is completed, the request key number is received (508), and actual key data corresponding to the received request key number is transmitted (509).

On the other hand, if it is confirmed that normal key data is received in the process of checking whether or not the normal key data is received, the PC 201 checks an internal error state and sends a connection allowance signal or a connection not available signal according to the error check result. (302).

Subsequently, after receiving (511) the name (Code_name) of the key data file for downloading, the number (Code_length) of data to be downloaded again is received (512). Subsequently, after receiving the actual key data as much as the number of data to be downloaded (513), and receives a checksum for checking whether the data has failed (514).

Finally, the checksum of the downloaded key data is examined and, according to the result, a normal signal for the key data or a fault signal for the key data is transmitted (515).

Although the technical idea of the present invention has been described in detail according to the above preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

As described above, the present invention is capable of transmitting and exchanging keys even in an environment in which a computer network is not provided by using a dial-up modem of a PSTN, which is required for applying a public key cryptosystem to a communication terminal on a PSTN. The public key cryptography system can be applied to PSTN communication terminals that do not have a computer network, and in particular, it is possible to transmit data in a general telephone network that is somewhat more secure than a computer network. In terms of utilization, there is a very good effect that can be used for the transmission of relatively important data requiring safety compared to computer networks.

Claims (9)

In the key transmission device for transmitting a key (Key), Storage means for storing a key delivered from a personal computer; Control command input means for inputting a control command for controlling the key transmission device; Connection means for connecting signals transmitted and received between the electronic switch and the terminal and the key transmission device; A dual-tone multi-frequency signal for receiving and transmitting a dual-tone multi-frequency signal transmitted from the electronic switch through the connection means, and providing a dual-tone multi-frequency signal to the terminal through the connection means under the control of the control means. Generating and receiving means; Modulation and demodulation means for modulating the key transmitted from the control means and transmitting the modulated key to the connection means, and demodulating the key transmitted from the connection means to the control means; Store the key transmitted from the personal computer in the storage means, and control the connection means and the demodulation means while transferring the key stored in the storage means to the demodulation means according to a control command input through the control command input means. And control means for receiving the dual tone multi-frequency signal from the dual tone multi-frequency signal generating and receiving means and controlling the dual tone multi-frequency signal generating and receiving means; And Matching means for matching keys transmitted and received between the personal computer and the control means Key transmission device using a modem comprising a. The method of claim 1, Display means for displaying an internal state of the key transmission device transmitted from the control means Key transmission device using a modem further comprising a. The method according to claim 1 or 2, On off-line, the control means downloads the key from the personal computer and stores it in the storage means. On-line, the control means transmits the key stored in the storage means to the demodulation means through a connection with the other terminal. In a key transmission method for transmitting a key through a public switched telephone network (PSTN), A first step of performing transmission and reception of a key according to whether a memory is normal; A second step of receiving a key by being connected to a personal computer off-line; A third step of storing a key received from the personal computer in the memory; And A fourth step of transmitting a key stored in the memory online through a modem connection with a counterpart Key transmission method using a modem made, including. The method of claim 4, wherein The first step is, A fifth step of determining whether the memory is normal; A sixth step of stopping transmission and reception of a key if the memory is not normal as a result of the determination in the fifth step; And A seventh step of determining that the key received from the personal computer is normal if the memory is normal as a result of the determination in the fifth step; An eighth step of determining whether a ring signal is received if the key is not normal as a result of the determination in the seventh step; A ninth step of skipping to the fifth step if the ring signal is not received as a result of the determination in the eighth step; A tenth step if the ring signal is received as a result of the determination in the eighth step, the process proceeds to the second step; And As a result of the determination in the seventh step, if the key is normal, the eleventh step is passed to the fourth step. Key transmission method using a modem made, including. The method of claim 4, wherein The second step, A fifth step of inquiring whether a connection with the personal computer is possible; A sixth step of checking whether an internal failure is detected and transmitting accessibility with the personal computer according to a failure inspection result; A seventh step of transmitting, by the personal computer, a name of a key file for down loading, according to whether the personal computer is accessible; An eighth step of transmitting, by the personal computer, the number of data to be downloaded; A ninth step of transmitting, by the personal computer, actual data as many as the number of data to download; The tenth step of transmitting, by the personal computer, a check_sum for checking whether a key is failed; And An eleventh step of checking the checksum of the key downloaded therein and transmitting whether the key is normal to the personal computer according to the check result Key transmission method using a modem made, including. The method of claim 6, The sixth step, A twelveth step of suspending access to the personal computer when an internal failure check results in an internal failure; And As a result of the internal failure inspection, if no internal failure occurs, the thirteenth step of establishing a connection with the personal computer is performed. Key transmission method using a modem made, including. The method of claim 4, wherein The fourth step is A fifth step of dialing a telephone number after the key receiving side hooks off to receive the key; A sixth step in which the key transmitting side is automatically hooked off after receiving the ring signal to transmit the dual tone multi-frequency signal to indicate that the key transmitting side is the key transmitting side; A seventh step of transmitting, by the key receiving side, its identifier using the received dual tone multi-frequency signal; An eighth step of performing a modem connection according to whether the identifier transmitted from the key receiving side and the identifier of the key transmitting side are the same; A ninth step, after the modem connection is completed, the key receiving side transmits a request key number; The tenth step of transmitting the actual key corresponding to the request key number; And An eleventh step of transmitting the result of receiving the actual key by the key receiving side Key transmission method using a modem made, including. The method of claim 8, The eighth step, A twelfth step of not performing a connection with the modem if the identifier transmitted from the key receiving side and the identifier of the key transmitting side are not the same; And A thirteenth step of connecting to the modem if the identifier transmitted from the key receiving side and the identifier of the key transmitting side are the same; Key transmission method using a modem made, including.