KR20020095776A - Method and apparatus for generating one-time secrete code - Google Patents

Abstract

PURPOSE: A method and a device for generating a disposable secrete key are provided to make a server and a client share the disposable secrete key for encrypting and decrypting the information in the real-time while not passing a transmission process using a communication network. CONSTITUTION: A transmitting/receiving part(110) performs the data communication with the client(200). A process generating part(130) generates a random number modification process for modifying a random number string transferred from the client and a secrete key generating process, and transmits the processes to the client. A random number string managing part(110) generates the first modified random number string and a partial random number string. A random number string comparing part(120) compares the second modified random number string with the first modified random number string by receiving the second modified random number string information from the client(200). A secrete key generating part(150) generates the disposable secrete key by manipulating a partial common random number string of the first and the second modified random number string if the comparison is accorded.

Description

Method and apparatus for generating one-time secrete code

The present invention relates to a method and apparatus for generating a disposable secret key.

Recently, with the rapid growth of the information communication field, the transmission of information using a communication network is becoming a reality.

However, when the information is to be transmitted using the communication network in this way, it is difficult to maintain the security of the information due to 'tapping' or 'hacking' on the Internet.

Therefore, in order to secure the information from such 'tapping' or 'hacking', the information transmitting side performs encryption on the information, and the receiving side of the information undergoes a process of decrypting the information, Techniques for preventing the leakage of information are developing.

This technique is commonly referred to as a cryptographic algorithm, and a procedure diagram for a general cryptographic algorithm is shown in FIG.

FIG. 1 illustrates an encryption algorithm for information when a certain client wants to transmit information requiring security such as his / her personal information to a server in order to receive a desired service from a server in a server / client structure.

That is, if any client 10 generates information to be sent to the server 20 (s10), encrypts the information (s20) and then transmits the encrypted information to the server side (s30), the server 20 The encrypted information is decrypted (s40) and its contents are decrypted.

These encryption algorithms are classified into a secret key encryption algorithm using the same key for encryption and decryption and a public key encryption algorithm using different keys for encryption and decryption, depending on the type of key that encrypts and decrypts the information.

The present invention relates to a secret key cryptographic algorithm, which is also referred to as a symmetric key cryptographic algorithm or a single key algorithm due to the feature of using the same key in encryption and decryption. The secret key cryptographic algorithm has a long history, and it is easy to interoperate with many existing information technologies, powerful data throughput, and easy to develop an appropriate cryptographic algorithm for the system environment. However, since the same key must be shared between the information exchange parties, there is a disadvantage in that a large number of keys must be maintained when exchanging information with multiple people. In other words, the secret key encryption algorithm generates a key used in the encryption and decryption process (hereinafter referred to as a "secret key") by a simple substitution and permutation combination, so that the encryption and decryption speed is fast, and the length of the secret key is increased. On the other hand, the number of keys to be managed is increased according to the increase of users, and the frequency of key changes is high.

Therefore, in recent years, a so-called one-time secret key scheme has been adopted to generate and provide a secret key necessary for information exchange parties in real time. However, in the case of such a one-time secret key method to share the one-time secret key using a communication network, there is a risk that the secret key can be leaked to a third party due to 'tapping' or 'hacking'. In particular, in the case of sending / receiving financial transaction information between a server and a member (client) for providing a financial transaction service or an e-commerce related service to a member, such a risk is borne by both the server and the member (client). Fatal to

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, the server and the client can share in real time a one-time secret key for encryption and decryption of information without going through a transmission process using a communication network An object of the present invention is to provide a method and apparatus for generating a disposable secret key.

1 is a process diagram for a general encryption algorithm,

2 is a flowchart illustrating a method for generating a disposable secret key according to an embodiment of the present invention;

3 is a process diagram for an encryption algorithm according to an embodiment of the present invention;

4 is an exemplary diagram of random numbers generated in the process of generating a disposable secret key according to an embodiment of the present invention;

5 is a schematic block diagram of a disposable secret generating device according to an embodiment of the present invention;

6 and 6A illustrate an embodiment of a deformation process structure for an initial random number sequence;

7 and 7A illustrate an embodiment of a process structure for generating a secret key by partial random sequence;

♣ Explanation of symbols for the main parts of the drawing ♣

100: disposable secret key generation 110: random number management unit

120: random number sequence 130: process generation unit

140: transmitter / receiver 150: secret key generation unit

In order to achieve the above object, the method for generating a disposable secret key of the present invention generates a random random sequence when a request for information transfer between a server and a client occurs, thereby allowing the random sequence N to be shared between the client and the server. And a second process of respectively generating a modified random number sequence M _s and M _c by which the server and the client transform the random number sequence by the same random number modification process P1 shared between the server and the client, and the server And a third process of checking whether the modified random number sequences M _s and M _c are identical by exchanging information on the modified random number sequences M _s and M _c through a communication network, and in the third process. When it is confirmed that each modified random number sequence (M _s , M _c ) matches, the server and the client respectively select the common partial random sequence (CS _s , CS _c ) among the corresponding modified random sequence (M _s , M _c ). Fourth process, the server and the client A fifth step of generating the same secret key (KEY _s , KEY _c ) by manipulating the common partial random sequence (CS _s , CS _c ) by the same secret key generation process (P2) It features.

In addition, the apparatus for generating a disposable secret key of the present invention for achieving the above object in the apparatus for generating a disposable secret key for encrypting and decrypting the information when an information transmission / reception command with an external client connected via a communication network occurs; , A random number sequence generating a random number sequence including a plurality of random numbers and a transmitting / receiving unit performing data transmission / reception, a plurality of random numbers, and transmitting the random number sequence (N) to the corresponding client. A generator generates a random number transformation process P1 for transforming the random number sequence N and a secret key generation process P2 for generating a disposable secret key, and generates the random number transformation process P1 and the secret key generation process. A process generation unit for transmitting (P2) to the corresponding client, and the first modified random number sequence M _S by modifying the random number sequence N based on the random number transformation process P1. ) And a random number sequence management unit for generating a partial random number sequence necessary for generating a disposable secret key by the first modified random number sequence (M _S ), and a random number sequence (by the random number transformation process (P1) from the client). receiving a modified random number sequence of a second modified random number sequence (M _C) information of N), the second modified random number sequence (M _C) and the first variation I i which determines the correspondence if the sequence (M _S) sequence In the case where the comparison unit and the random number sequence comparison unit determine that the first modified random number sequence M _S and the second modified random number sequence M _C coincide with each other, the first modified eggs are generated by the secret key generation process P2. And a secret key generation unit for generating a disposable secret key by manipulating a common partial random number sequence of the sequence MS and the second modified random number sequence MC.

Hereinafter, a preferred embodiment of a disposable secret key generation method and apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a flowchart illustrating a method for generating a disposable secret key according to an embodiment of the present invention. Referring to FIG. 2, when an information transfer request is generated between a server and a client, a random random number N is first generated (S110), and the random number N is shared between the client and the server (S120). In this case, the random number sequence N includes a plurality of random numbers, and occurs in a client, a server, or a separate random number generating device, and then is transmitted and shared to the server and the client by using a communication network.

When the random number string N is shared by the server and the client as described above, the random number string M is modified by modifying the random number string N by the same random number modification process P1 shared between the server and the client. _s: a server-side modified random number sequence, M _c: generate a client-side modified random number sequence), respectively (s130). At this time, the server and the client may share the same random number transformation process (P1) in advance, and when generating a disposable secret key by requesting information transfer between the server and the client, the server side generates a new random number transformation process (P1). Alternatively, one of the randomly generated random number transformation processes P1 may be randomly selected and then transmitted to the client side. In this way, a general communication network is used to transmit the process P1 from the server side to the client side. In general, since the process is difficult to eavesdrop or hack through the communication network, the leakage of the secret key is almost impossible.

On the other hand, if each of the modified random number sequence (M _s , M _c ) generated by each server and client side, and performs a process (s140) to check whether the modified random number sequence (M _s , M _c ) match each other, At that time, the server and the client exchange information of each modified random number sequence (M _s , M _c ). That is, the server randomly selects a partial random number sequence (S _s ) for the corresponding modified random number sequence (M _s ), and the client side randomly selects a partial random sequence (S _c ) for the corresponding modified random sequence (M _c ). Is selected, the client-side modified random number sequence (M _c ) includes the server-side partial random number sequence (S _s ), and the server-side modified random number sequence (M _s ) includes the client-side partial random number sequence (S _c ). Check whether this is included.

When it is confirmed by the process s140 that the modified random number sequences M _s and M _{c of} the server and the client match each other, the server and the client have a common part among the modified random number sequences M _s and M _c . Random sequences CS _s and CS _c are respectively selected (s150). That is, the partial random number sequences S _s and S _c are removed from each of the modified random numbers M _s and M _c generated by the server and the client, respectively. CS _s , CS _c ).

Then, by the same secret key generation process P2 shared between the server and the client, the common partial random number sequences CS _s and CS _c are operated to generate the same secret keys KEY _s and KEY _c , respectively ( s160). At this time, the server and the client may share the same secret key generation process P2 in advance, as in the case of the random number transformation process P1, or when the secret key is generated by the information transfer request, the server side and the client side. In the latter case, the server generates a new secret key generation process (P2) or randomly selects one of a plurality of pre-generated secret key generation processes (P2) and then selects the secret. The key generation process P2 is sent to the client side. In this case, since the eavesdropping or hacking of the secret key generation process P2 through the communication network is difficult, the leakage of the secret key is almost impossible.

3 is a flowchart illustrating a cryptographic algorithm according to an embodiment of the present invention, and FIG. 4 is a diagram illustrating random numbers generated in the process of generating a disposable secret key according to an embodiment of the present invention.

The encryption algorithm according to an embodiment of the present invention will be described in more detail with reference to FIGS. 3 and 4 as follows.

3 illustrates an example of a case where the client 10 generates an initial random number N for generating a secret key. However, the initial random number sequence N may occur in the server 20 or may be generated using a separate random number generator.

Referring to FIG. 3, first, the client 10 generates a random number sequence N (s201), and then transmits the random number sequence N to the server 20 to inform that there is information to be transmitted to the server 20 side. (s202). In this case, the generated random number N may be illustrated as shown in FIG. 4A for convenience of description. That is, the random number sequence N includes n random numbers, and the random numbers N ₁ , N ₂ ,... , N _n .

Then, the server 20 selects the random number modification process P1 for transforming the random number sequence N, and transmits it to the client 10 (s203 and s204). In this case, if the client 10 and the server 20 share the same random number transformation process P1 in advance, the processes s203 and s204 may be omitted.

When the server 20 and the client 10 share the same random number transformation process P1 in this manner, the server 20 and the client 10 modify the random number sequence M based on the random number transformation process P1. Are generated respectively (s205 and s206). At this time, the modified random number sequence can be shown as (M _s: a random number sequence modifications on the client side: the server-side I variant in sequence, M _c) are also for convenience of explanation, 4 (b). That is, the server-side modified random number sequence M _s includes 'n-1' random numbers, and the random numbers are M ₁ , M ₂ ,... , M _n-1 . The client-side modified random number sequence M _c is thus constructed.

At this time, the number of random numbers decreased from 'n' to 'n-1' during the transformation from the initial random number (N) to the modified random number (M _s , M _c ). This is because the last random number of the initial random number (N) is used to indicate the start and end of the random number, which is just one example, so the change in the number of the random numbers can be ignored.

If the modified random number sequences M _s and M _c are generated at both sides of the server 20 and the client 10 as in the processes s205 and s206, respectively, whether the modified random number sequences M _s and M _c are identical A series of processes s207 to s210 are performed to determine.

First, the server 20 selects a partial random number sequence S _s for the modified random number sequence M _s (s207), and transmits the partial random number sequence S _s to the client side (s208). Then, the client 10 has the modified random number sequence (M _c) that part random number sequence (S _s) random number sequence (S _s) is the strain the portion to determine whether or not including a random number sequence (M _c) to If included, the random random sequence (S _c ) is selected as the random random sequence (S _c ) from the modified random number sequence (M _c ), and the partial random sequence (S _c ) is transmitted to the server 20 (s210). Then, the client 10 selects the residual random number sequence from which the partial random number sequences S _s and S _c are removed from the modified random number sequence M _c as the common partial random number sequence CS _c (S211).

4 (c) randomly selects i (M ₁ ,.., M _i ) partial random number sequences (S _s ) from the server-side modified random number sequence (M _s ), and the partial random number sequence (S _s ) is represents the step of determining whether or not the client-side modification I comprising the sequence (M _c), Figure 4 (d) is a client-side modified random number sequence (M _c) any random number j dog (M _{i + 1,} in ..., portion consisting of M _{i + j)} i selected as the sequence (S _c) a random, and represents that part I process determines whether or not a sequence (S _c), the server-side modification I comprising the sequence (M _s).

On the other hand, the server 20 is the modified random number sequence (M _s), the part-random number sequence (S _c) said portion to determine whether or not including a random number sequence (S _c) is the transmission from client 10 to a modified I selects in sequence (M _s) of the case, the modified random number sequence (M _s) the partial random number sequence (s _s, s _c) to remove residual I intersection of random number sequence to sequence (CS _s) in contained in (s212) .

FIG. 4 (e) removes the partial random number sequences S _s , S _c (M ₁ ,... M _i , M _{i + 1} ,..., M _{i + j} ) from the server-side modified random number sequence M _s . the remaining I denotes the process of selecting a common partial random number sequence (CS _s) the sequence, Fig. 4 (f) is a client-side modified random number sequence random number sequence the portion of the _{(M c) (S s,} S c) (M 1, The process of selecting the residual random sequence from which ..., M _i , M _{i + 1} , ..., M _{i + j} ) is removed as the common partial random sequence CS _c is shown.

At this time, the server-side modified random number sequence (M _c ) does not include the server-side partial random number sequence (S _s ), or the server-side modified random number sequence (M _s ) does not include the client-side partial random number sequence (S _s ). The case terminates the secret key generation process.

As such, when the common partial random number sequences CS _s and CS _c are selected on the server 20 and the client 10 side, the server 20 manipulates the common partial random number sequences CS _s and CS _c to secret it. A secret key generation process P2 for generating a key is selected (s213) and transmitted to the client 10 (s214). In this case, if the client 10 and the server 20 share the same secret key generation modification process (P2) in advance, the processes (s213, s214) can be omitted.

Then, the client 10 and the server 20 generate the same secret keys KEY _s and KEY _c by the same secret key generation process P2 shared with each other (s214 and s215).

After the client 10 encrypts the information using the secret key KEY _c (s217), and transmits the encrypted information to the server 20 (s218), the server 20 encrypts the encrypted information. Information is decrypted using the generated secret key KEY _S (s219).

5 is a schematic block diagram of an apparatus for generating a secret key according to an embodiment of the present invention. Referring to FIG. 5, the one-time secret key generation device 100 for processing the one-time secret key generation method as described above is installed at a server side, and the random number sequence management unit 110, the random number sequence comparison unit 120, and process generation are provided. The unit 130, the transmitter / receiver 140 and the secret key generation unit 150.

At this time, since the secret key generation operation by the random number transformation process P1 and the secret key generation process P2 transmitted from the server must also be independently performed on the client side 200, the random number sequence management unit 210, an internal partition, The sequence comparator 220, the secret key generator 230, the transmitter and receiver 240, and the random number generator 250 are included.

The random number generation unit 250 is a device for generating and transmitting the random number sequence N, which is the basis of secret key generation, to the server side, and the remaining devices 210 to 240 are the same disposable secrets as the server based on the random number. As a device for generating a key, each operation is similar to that of the corresponding device included in the server side 100, and thus a detailed description thereof will be omitted.

At this time, all data transmission / reception between the server and the client is made through the transmitter / receiver 150, and the description of the transmitter / receiver 150 will be omitted below.

Process generation unit 140 generates a random number transformation process (P1) for modifying the random number sequence (N) transmitted from the client for generating a disposable secret key and a secret key generation process (P2) for generating a disposable secret key, and The random number transformation process P1 and the secret key generation process P2 are transmitted to the corresponding client. At this time, the process generating unit 140 generates a new random number modification process (P1) and a secret key generation process (P2), or among a plurality of pre-generated random number transformation process (P1) and secret key generation processes (P2) Each one process is randomly selected and sent to the client.

The random number sequence manager 120 transforms the random number sequence N based on the random number transformation process P1 generated or selected by the process generator 140 to generate a first modified random number sequence M _S , and generates the first modified random number sequence M _S. Generate a partial random number sequence required for generation of a disposable secret key by the modified random number sequence (M _S ). That is, the first partial random number sequence to be transmitted to the client to determine whether the first modified random number (M _S ) and the second modified random number sequence (M _C ) generated by the client and the first modified random number sequence ( M _S ) and when the second modified random number sequence M _C coincides with each other, a second partial random number sequence that is a common partial random sequence of the first modified random sequence M _S and the second modified random sequence M _C is generated. do. The secret key generator 160 manipulates the second partial random number sequence to generate a desired disposable secret key.

The random number comparison unit 130 receives second modified random number sequence M _C , which is a modified random number sequence of the random number sequence N by the random number transformation process P1, from the client, and receives the second modified random number sequence M _C. ) And the first modified random number sequence (M _S ) is determined. That is, the second modified random number sequence (M _C), the client confirming that the first section I comprises a sequence a second modification to the random number sequence (M _C) a first portion random number sequence are different partial random number sequence in the third portion random number sequence from the In this case, the random number comparing unit 130 determines whether the third partial random number sequence is included in the first modified random number sequence M _S , and the third partial random number sequence includes the first modified random number sequence ( When it is included in M _S ), it is determined that the first modified random number sequence M _S and the second modified random number sequence M _C match.

Secret key generation unit 160, if the first modified random number (M _S ) and the second modified random number sequence (M _C ) matched as a result of the determination of the random number sequence comparison unit 130, the secret key generation process (P2) By manipulating a common partial random number sequence CS (for example, the second partial random number sequence generated by the random number sequence manager 120) of the first modified random number sequence M _S and the second modified random number sequence M _C. Create a disposable secret key.

6 and 6A show an embodiment of the structure of the deformation process (P1) 215 for the initial random number sequence, and FIGS. 7 and 7A show a process (P2) for generating a secret key by partial random number sequence. 245 is a diagram showing an embodiment of the structure.

First, referring to FIG. 6, as an example of a case where the initial random number sequence includes '7' random numbers, the last one of the '7' random numbers is used to identify the beginning and end of the random number sequence. As shown in FIG. 6, the random number finally inputted to the random number transformation process P1 215 is six (N ₁ ,..., N ₆ ), and the modified random number sequence M output as a result of the processing. ) Also contains six random numbers (M ₁ ,…, M ₆ ). FIG. 6A is a configuration example of such a random number transformation process (P1) 215. Referring to the example shown in FIG. 6A, the random number transformation process (P1) uses the ASC2BIN () function for each random number (ASC code) composed of 16 bytes. After converting the binary code into 8 bytes, the modified random number sequence is generated through a plurality of logic circuits (XOR) as shown in FIG. 6A. The random sequence is then converted to 16-byte ASCII code via the BIN2ASC () function and output. At this time, the random number deformation process (P1) 215 shown in Figure 6a is only one embodiment, it is possible to apply a random number deformation process (P1) 215 composed of various circuits. In other words, it is possible to generate almost infinite number of random number transformation processes for converting the bit stream of the input random number, it is possible to select and use one of such random number transformation processes.

On the other hand, referring to Figure 7, the secret key generation process (P2) 245 is related to the number of the input random number sequence when the 'm' common partial random number sequence (CS) selected in common at the server and the client is input A 32-byte secret key is generated in common, and a configuration example of the secret key generation process (P2) 245 is shown in FIG. 7A. Referring to the example illustrated in FIG. 7A, the secret key generation process (P2) 245 first generates a 40-byte hash for 'm' 16-byte random numbers that are included in the common partial random number sequence (CS) (H). )do. The 40-byte hash is divided into five 8 bytes (D) for bit manipulation. First, five 8-byte ASCII codes are converted into four-byte binary codes by the ASC2BIN () function. The four 4-byte binary codes are bit-manipulated through a number of logic circuits (XORs) as shown in FIG. 7A, and then again the four 8-byte ASC codes (A, B, C, D) by the BIN2ACS () function. ) Is generated. Therefore, when these four ASC codes (A, B, C, D) are combined, a 32-byte secret key is generated.

At this time, the secret key generation process (P2) 245 shown in FIG. 7A is also just one embodiment and can be modified into various circuits.

The above description is only for explaining one embodiment, and the present invention is not limited to the above-described embodiment and can be variously changed within the scope of the appended claims. For example, the shape and structure of each component specifically shown in the embodiment of the present invention can be modified.

In the method and apparatus for generating a disposable secret key of the present invention as described above, the server and the client share the same process for generating the same secret key, so that when the client and the server transfer information, the server and the client by the same process By generating the same secret key for encrypting and decrypting the information to be transmitted from each side, there is an effect that the server and the client can share the same secret key without directly transmitting and receiving the secret key through the communication network. Therefore, the secret key can be prevented from leaking to third parties due to eavesdropping on the telephone network, hacking on the Internet, or the like.

In particular, since eavesdropping a process through a communication network is quite difficult, a secret key may be implemented to transmit a process generated at one side (eg, a server) using a communication network so that the server and the client share the same process. Security can be maintained.

Claims (11)

In the one-time secret key generation method for encrypting and decrypting information transmitted between the server and the client, A first process of generating a random random sequence when a request for information transfer between the server and the client occurs, and sharing the random sequence N between the client and the server; A second process of generating a modified random number sequence M _s and M _c by which the server and the client transform the random number sequence by the same random number modification process P1 shared between the server and the client, and A third process of checking whether the modified random number sequences M _s and M _c coincide by exchanging the modified random number sequences M _s and M _c through the communication network; When it is confirmed that each modified random number sequence M _s and M _c matches in the third process, the server and the client share a common partial random number sequence CS _s and CS _c among the corresponding modified random number sequences M _s and M _c . 4th process of selecting each), A fifth step of generating the same secret key (KEY _s , KEY _c ) by manipulating the common partial random sequence (CS _s , CS _c ) by the same secret key generation process (P2) shared between the server and the client Disposable secret key generation method comprising a. The method of claim 1, wherein the first process is And generating a random number sequence including a plurality of random numbers from a client, a server, or a separate random number generator, and transmitting the random number sequence to the server and the client using a communication network. The method of claim 1, wherein the second process After the server generates a random number transformation process (P1) or randomly selects a random number transformation process (P1) of one of a plurality of pre-generated random number transformation processes, and sends the random number transformation process (P1) to the client Disposable secret key generation method characterized in that it further comprises. The method of claim 1, wherein the third process is After the server and the client select different partial random numbers (S _s , S _c ) for the modified random numbers (M _s , M _c ) generated in the second process, respectively, the partial random numbers (S _s , S) _c ) exchanging and checking whether the partial random number sequence (S _s , S _c ) is included in the other modified random number sequence (M _c , M _s ), respectively. The method of claim 1 or 4, wherein the third process The partial random number sequence _{(S s,} S _c) to exchange with the part-random number sequence _{(S s,} S _c) is the other modified random number sequence than the process of confirming whether or not included, respectively (M _c, M _s) once Disposable secret key generation method, characterized in that performed. The method of claim 1 or 4, wherein the fourth process After removing all of the partial random numbers (S _s , S _c ) from each of the modified random numbers (M _s , M _c ) generated by the server and the client, the remaining partial random numbers sequence is a common partial random number sequence of the server and the client ( CS _s , CS _c ) The one-time secret key generation method characterized in that the selection. The method of claim 1, wherein the fifth process After the server generates the secret key generation process (P2) or randomly selects a secret key generation process (P2) of one of a plurality of pre-generated secret key generation processes, the client generates the secret key generation process (P2). Secret key generation method further comprising the step of transmitting to. An apparatus for generating a disposable secret key for encrypting and decrypting information when an information transmission / reception command with an external client connected to a communication network occurs, A transmission / reception unit that performs data transmission / reception with a client that is the target of transmission / reception of the information, Generate a random number modification process P1 for transforming the random number sequence N sent from the client for generation of the disposable secret key and the secret key generation process P2 for generating the disposable secret key, and the random number transformation process P1. And a process generating unit for transmitting the secret key generation process (P2) to the client, Based on the random number deformation process (P1) to modify the random number sequence (N) to generate a first modified random number sequence (M _S ), to generate a disposable secret key by the first modified random number sequence (M _S ) A random sequence manager that generates a partial random sequence required; The second modified random number sequence M _C , which is a modified random number sequence of the random number sequence N by the random number transformation process P1, is received from the client, thereby receiving a second modified random number sequence M _C and the first modified sequence. A random sequence comparison unit for determining whether or not the random sequence (M _S ) is identical, As a result of the determination of the random number comparing unit, when the first modified random number sequence (M _S ) and the second modified random number sequence (M _C ) match, the first modified random number sequence (M _S ) is performed by the secret key generation process (P2). And a secret key generator for generating a disposable secret key by manipulating a common partial random number sequence of the second modified random number sequence (M _C ). The method of claim 8, wherein the process generating unit One-time secret key generation device, characterized in that for each randomly selected one of the plurality of random number transformation process (P1) and the secret key generation process (P2) generated in advance to transmit to the client. The method of claim 8, wherein the random number management unit A first partial random number sequence to be transmitted to a client to determine whether the first modified random number sequence (M _S ) and the second modified random number sequence (M _C ) match each other; and the first modified random number sequence (M _S ); When the second modified random number sequence (M _C ) coincides, a second partial random number sequence, which is a common partial random sequence of the first modified random sequence (M _S ) and the second modified random number sequence (M _C ), is generated. Disposable secret key generation device. The method of claim 8 or 10, wherein the random sequence comparison unit The second modified random number sequence partial random number sequence in the third part-random number sequence of (M _C) of the first portion I from the client finds that it contains the sequence of the first partial random number sequence are different from the second modified random number sequence (M _C) to receives the third partial random number sequence is the first modified random number sequence of the first variant, if included in the (M _S) random number sequence (M _S) and second modified random number sequence (M _C) to determine that a match Disposable secret key generating device, characterized in that.