KR102561247B1 - Method for transmitting data using a secret distributed - Google Patents

Abstract

The present invention relates to a data transmission method using secret distribution, wherein a user terminal and an issuing server distribute and store secret data of a user using secret distribution, generate a certificate, and when a verification terminal receives the certificate from the user terminal, The distributed data of the user is received through the issuing server, and the secret data is restored and verified using the received distributed data and certificate.

Description

Data transmission method using secret distribution {METHOD FOR TRANSMITTING DATA USING A SECRET DISTRIBUTED}

The following embodiments relate to a secure data transmission technique, and in particular, to a technique for transmitting confidential data to safely deliver personal confidential data shared with a trusted institution to a third party or other person.

As terminals become high-performance/high-capacity, the importance of protecting and managing confidential data, which is important data inside the terminal, is emerging.

In order to protect and manage such secret data, a method of encrypting secret data of a terminal and storing them in an external storage device for backup has been conventionally used.

However, when secret data is stored in an external storage device, if the storage device is hacked, secret data may be easily leaked.

Therefore, there is a need for a more secure method for storing confidential data in an external storage device.

In addition, there is a demand for a method of safely sending confidential data to other people or institutions.

An object of the present invention is to provide a data transmission method using secret distribution.

A data transmission method using secret distribution according to an embodiment of the present invention includes transmitting secret data from a user terminal to an issuing server; requesting certificate issuance from the user terminal to the issuing server; distributing the secret data into a plurality of pieces using a cryptographic secret distribution algorithm in the issuing server; selecting one of the pieces distributed by the issuing server as a third distribution piece and generating a verification value with the third distribution piece; selecting, in the issuing server, one of the distributed pieces except for the third distribution piece as a first distribution piece, and generating a certificate including the first distribution piece and the verification value; selecting, in the issuing server, other than the first distribution pieces and the third distribution pieces from among the distributed pieces as second distribution pieces, and storing the second distribution pieces and the verification value; and transmitting the certificate from the issuing server to the user terminal.

At this time, the step of distributing the secret data into a plurality of pieces using a cryptographic secret distribution algorithm in the issuing server may include dividing the secret data into a plurality of pieces using a secret distribution algorithm defined in the Shamir Secret Sharing technique. can be dispersed into fragments of

In this case, in the generating of the verification value, the verification value may be generated by hashing the third distributed fragment.

In this case, in the generating of the certificate including the first distributed fragment and the verification value, the certificate may be generated by digitally signing the first distributed fragment and the verification value with the signature of the issuing server.

At this time, the data transmission method using secret distribution may include generating a signed certificate by digitally signing the certificate in the user terminal; transmitting the signed certificate from the user terminal to a verification terminal; verifying the signed certificate at the verification terminal and obtaining the certificate; extracting the first distributed fragment and the verification value included in the certificate in the verification terminal; transmitting the verification value from the verification terminal to the issuing server and requesting a distributed fragment required for recovery of the secret data; checking whether the verification value stored in the issuing server and the verification value received from the verification terminal match when the issuing server receives a request for distributed fragments; in the issuing server, when the verification value stored in the issuing server and the verification value received from the verification terminal match, searching for the second distributed fragment stored in the issuing server and transmitting the same to the verification terminal; generating recovered secret data by recovering secret data from the first distributed fragment and the second distributed fragment received from the issuing server using a secret recovery algorithm corresponding to the secret distribution algorithm in the verification terminal; generating a recovered third distributed fragment by recovering a third distributed fragment from the recovered secret data and the first distributed fragment using the secret recovery algorithm in the verification terminal; and the verification terminal generates a temporary verification value using the recovered third distributed fragment, and if the temporary verification value matches the verification value included in the certificate, the recovered secret data is identical to the secret data. A confirmation step may be further included.

In this case, the verifying the signed certificate in the verification terminal and obtaining the certificate may include checking whether the signed certificate is electronically signed with the signature of the user of the user terminal, and the certificate included in the signed certificate It can be verified by checking whether the digital signature is signed with the signature of the issuing server.

At this time, the verification terminal generates a temporary verification value using the recovered third distributed fragment, and if the temporary verification value matches the verification value included in the certificate, the recovered secret data is identical to the secret data In the step of confirming that it is, the temporary verification value may be generated by hashing the restored third distributed fragment.

A data transmission method using secret distribution according to another embodiment of the present invention includes transmitting secret data from a user terminal to an issuing server; distributing the secret data into a plurality of pieces using a cryptographic secret distribution algorithm in the user terminal; selecting one of the fragments distributed in the user terminal as a third distributed fragment and generating an issuer verification value using the third distributed fragment and the secret data; selecting a first distributed fragment to be included in a certificate from among the distributed fragments in the user terminal; The user terminal selects other distributed pieces other than the first distributed piece and the third distributed piece from among the distributed pieces as a second distributed piece, and transmits the second distributed piece and the issuer verification value to the issuing server. step; generating a recovered third distribution fragment by recovering a third distribution fragment from the second distribution fragment and the issuer verification value by using a secret recovery algorithm corresponding to the secret distribution algorithm in the issuing server; generating a temporary issuer verification value by using the secret data and the restored third distributed fragment in the issuing server, and verifying whether the temporary issuer verification value and the issuer verification value match; generating a verification value using the restored third distribution fragment and storing the verification value and the second distribution fragment when the temporary issuer verification value and the issuer verification value coincide with each other in the issuing server; transmitting the verification value from the issuing server to the user terminal; and generating a certificate including the first distributed fragment and the verification value when the user terminal receives the verification value.

In this case, the step of selecting one of the fragments distributed in the user terminal as the third distributed fragment and generating an issuer verification value using the third distributed fragment and the secret data, the secret data and the third distributed fragment. The issuer verification value can be generated by concatenating and hashing the pieces.

In this case, the step of generating a temporary issuer verification value using the secret data and the restored third distributed fragment in the issuing server and confirming whether the temporary issuer verification value and the issuer verification value match the secret data and The temporary issuer verification value may be generated by concatenating and hashing the recovered third distributed fragments.

In this case, in the issuing server, if the temporary issuer verification value and the issuer verification value match, generating a verification value using the restored third distribution fragment and storing the verification value and the second distribution fragment, The verification value may be generated by hashing the restored third distributed fragment.

At this time, when the user terminal receives the verification value, generating a certificate including the first distributed fragment and the verification value comprises using the first distributed fragment and the verification value as a signature of a user of the user terminal. The certificate may be generated by digital signature.

At this time, the data transmission method using secret distribution may include generating a signed certificate by digitally signing the certificate in the user terminal; transmitting the signed certificate from the user terminal to a verification terminal; verifying the signed certificate at the verification terminal and obtaining the certificate; extracting the first distributed fragment and the verification value included in the certificate in the verification terminal; transmitting the verification value from the verification terminal to the issuing server and requesting a distributed fragment required for recovery of the secret data; checking whether the verification value stored in the issuing server and the verification value received from the verification terminal match when the issuing server receives a request for distributed fragments; in the issuing server, when the verification value stored in the issuing server and the verification value received from the verification terminal match, searching for the second distributed fragment stored in the issuing server and transmitting the same to the verification terminal; generating recovered secret data by recovering secret data from the first distributed fragment and the second distributed fragment received from the issuing server using a secret recovery algorithm corresponding to the secret distribution algorithm in the verification terminal; generating a recovered third distributed fragment by recovering a third distributed fragment from the recovered secret data and the first distributed fragment using the secret recovery algorithm in the verification terminal; and the verification terminal generates a temporary verification value using the recovered third distributed fragment, and if the temporary verification value matches the verification value included in the certificate, the recovered secret data is identical to the secret data. A confirmation step may be further included.

In this case, the verifying the signed certificate in the verification terminal and obtaining the certificate may include verifying whether the signed certificate is electronically signed with the signature of the user of the user terminal.

At this time, the verification terminal generates a temporary verification value using the recovered third distributed fragment, and if the temporary verification value matches the verification value included in the certificate, the recovered secret data is identical to the secret data In the step of confirming that it is, the temporary verification value may be generated by hashing the restored third distributed fragment.

The present invention relates to a data transmission method using secret distribution, wherein a user terminal and an issuing server distribute and store secret data of a user using secret distribution, so that even if the user terminal is lost or the issuing server is hacked, the security of the secret data is guaranteed. It can be maintained, and the user can safely transmit secret data by sending a certificate.

1 is a diagram showing a schematic configuration of a data transmission system using secret distribution according to an embodiment of the present invention.
2 is a flowchart illustrating a process of storing secret data in a user terminal and an issuing server and generating a certificate in the issuing server in a data transmission system according to an embodiment of the present invention.
3 is a flowchart illustrating a process of storing secret data in a user terminal and an issuing server and generating a certificate in a user terminal in a data transmission system according to an embodiment of the present invention.
4 is a flowchart illustrating a process of transmitting confidential data in a data transmission system according to an embodiment of the present invention.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, since various changes can be made to the embodiments, the scope of the patent application is not limited or limited by these embodiments. It should be understood that all changes, equivalents or substitutes to the embodiments are included within the scope of rights.

Terms used in the examples are used only for descriptive purposes and should not be construed as limiting. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the embodiment belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the present application, they should not be interpreted in an ideal or excessively formal meaning. don't

In addition, in the description with reference to the accompanying drawings, the same reference numerals are given to the same components regardless of reference numerals, and overlapping descriptions thereof will be omitted. In describing the embodiment, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the embodiment, the detailed description will be omitted.

In addition, in describing the components of the embodiment, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, order, or order of the corresponding component is not limited by the term. When an element is described as being “connected,” “coupled to,” or “connected” to another element, that element may be directly connected or connected to the other element, but there may be another element between the elements. It should be understood that may be "connected", "coupled" or "connected".

Components included in one embodiment and components having common functions will be described using the same names in other embodiments. Unless stated to the contrary, descriptions described in one embodiment may be applied to other embodiments, and detailed descriptions will be omitted to the extent of overlap.

Hereinafter, a data transmission system and method using secret distribution according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4 attached.

1 is a diagram showing a schematic configuration of a data transmission system using secret distribution according to an embodiment of the present invention.

Referring to FIG. 1 , a data transmission system using secret distribution may include a user terminal 110 , an issue server 120 and a verification terminal 130 .

The user terminal 110 and the issuance server 120 distribute and store user secret data using a secret distribution method, and generate a certificate proving that the user permits the transmission of the secret data.

The certificate may be generated through the user terminal 110 or the issuing server 120. In FIG. 2, a case in which the issuing server 120 generates the certificate is described, and in FIG. 3, the user terminal 110 generates the certificate explain the case

When the verification terminal 130 receives the certificate from the user terminal 110, it receives the distributed data of the user through the issuing server 120, recovers the secret data using the received distributed data and the certificate, and verifies the confidential data. can

Details of receiving a certificate, recovering secret data, and verifying the verification terminal 130 will be described later in detail with reference to FIG. 4 .

Hereinafter, the method according to the present invention configured as described above will be described with reference to the drawings below.

2 is a flowchart illustrating a process of storing secret data in a user terminal and an issuing server and generating a certificate in the issuing server in a data transmission system according to an embodiment of the present invention.

Referring to FIG. 2 , the user terminal 110 transmits secret data S to the issuing server 120 (210).

Then, the user terminal 110 requests certificate issuance to the issuing server 120 (212).

Thereafter, the issuing server 120 distributes the secret data into a plurality of pieces C1, C2, and C3 using a cryptographic secret distribution algorithm (214).

The secret data (S) is distributed into multiple (n) pieces using a cryptographic secret distribution technique having a threshold (t, threshold). At this time, n is greater than t+1.

The secret data (S) is distributed into n pieces (c1, c2, ??, cn), and S can be recovered only when t+1 or more distributed pieces are gathered.

Secret Sharing may be performed as in the example of Equation 1 below.

[Equation 1]

(c1, c2, ??, cn) = SS(S)

Here, c1, c2, ??, cn are distributed pieces, S is secret data, and SS() is a secret distribution algorithm corresponding to a cryptographic secret distribution technique.

Secret Reconstruct may be performed as in the example of Equation 2.

[Equation 2]

S = SR(c1, c2, ??, ct+1)

Here, c1, c2, ??, ct+1 are distributed fragments, t is a threshold value with characteristics of (n > t+1), S is secret data, and SR is a secret recovery algorithm.

In this case, a Shamir Secret Sharing technique may be applied as a cryptographic secret distribution technique, and a detailed description of the Shamir Secret Sharing technique will be described later after FIG. 4 .

In step 214, the issuing server 120 uses the secret distribution algorithm (SS) defined in the Shamir Secret Sharing technique to divide the secret data into a plurality of pieces (C1, C2) as shown in Equation 3 below. , C3).

[Equation 3]

(C1, C2, C3) = SS(S)

Here, C1 is one of the distributed pieces (c1, c2, ??, cn) included in the certificate and is referred to as the first distributed piece, and C3 is a verification value among the distributed pieces (c1, c2, ??, cn) One of the dispersion pieces selected to generate is called the third dispersion piece, and C2 is the dispersion pieces (c1, c2, ??, ct+ 1) is called the second distributed fragment, S is the secret data, and SS() is the secret distribution algorithm.

That is, the number of second dispersion pieces may be plural.

The issuing server 120 selects one of the distributed pieces as the third distribution piece C3 and generates a verification value V with the third distribution piece C3 (216). At this time, the selection of the third dispersion pieces C3 may be selected regardless of the order of the dispersed pieces.

In step 216, the issuing server 120 generates a verification value (V) by hashing the third distributed piece (C3) as in the example of Equation 4 below. The secret distribution algorithm recovers to an undesirable value if any one of the distribution pieces used for recovery is incorrect. A verification value (V) is used to confirm that the recovered secret data (S') and the original secret data (S) are the same.

[Equation 4]

V = Hash(C3)

Here, V is the verification value, C3 is the third distributed fragment, and Hash() is the hash function.

The issuing server 120 selects one of the distributed pieces (C1, C2, C3) except for the third distributed piece (C3) as the first distributed piece (C1), and selects the first distributed piece (C1) and the verification value. A certificate (VC) including (V) is generated (218). At this time, the selection of the first dispersion pieces C1 may be selected regardless of the order of the dispersed pieces.

In step 218, the issuing server 120 digitally signs the first distributed piece (C1) and the verification value (V) with the signature of the issuing server 120 as in the example of Equation 5 below to generate a certificate (VC) can do.

[Equation 5]

VC = Sign(C1, V)

Here, VC is a certificate, V is a verification value, C1 is a first distributed fragment, and Sign() is a digital signature.

At this time, the issuer's signature used in Sign() may be generated by the issuer based on a decentralized identifier (DID) or public key infrastructure (PKI).

The issuing server 120 selects the rest of the distributed pieces (C1, C2, C3) except for the first distributed piece (C1) and the third distributed piece (C3) as the second distributed piece (C2), and the second distributed piece (C2). The variance fragment (C2) and the verification value (V) are stored (220). At this time, the number of second dispersion pieces C2 may be plural. When the issuing server 120 stores the second distributed piece C2 and the verification value V, it deletes the secret data S received from the user terminal 110.

Then, the issuing server 120 transmits the certificate VC to the user terminal 110 (222).

On the other hand, when the user terminal 110 receives the certificate (VC), the secret data (S) can be deleted for security. Secret data can be recovered by performing steps 416 to 428.

3 is a flowchart illustrating a process of storing secret data in a user terminal and an issuing server and generating a certificate in a user terminal in a data transmission system according to an embodiment of the present invention.

Referring to FIG. 3 , the user terminal 110 transmits secret data S to the issuing server 120 (310).

Then, the user terminal 110 distributes the secret data into a plurality of pieces using a cryptographic secret distribution algorithm (312).

In step 312, the user terminal 110 divides the secret data into a plurality of pieces (C1, C2, C3) as in <Equation 1> using the secret distribution algorithm (SS) defined in the Shamir Secret Sharing technique. can be distributed as

The user terminal 110 selects one of the distributed pieces C1, C2, and C3 as the third distributed piece C3, and uses the third distributed piece C3 and the secret data S to verify the issuer verification value. (IV) is generated (314). At this time, the selection of the third dispersion pieces C3 may be selected regardless of the order of the dispersed pieces.

In step 314, the user terminal 110 may concatenate the secret data S and the third distributed fragment C3 and hash them to generate an issuer verification value IV as shown in Equation 6 below.

[Equation 6]

IV = Hash(S||C3)

Here, IV is the issuer verification value, S is the secret data, C3 is the third distributed fragment, and Hash() is the hash function.

The user terminal 110 selects the first distribution piece C1 to be included in the certificate from among the distributed pieces C1, C2, and C3, and selects the first distribution piece C1 from among the distributed pieces C1, C2, and C3. ) and the third distribution fragment (C3) are selected as the second distribution fragment (C2), and the second distribution fragment (C2) and the issuer verification value (IV) are transmitted to the issuing server 120 (316). . Through step 316, the user terminal 110 requests the issuing server 120 to store the user data (the second distributed piece C2 and the verification value V). At this time, the selection of the first dispersion pieces C1 may be selected regardless of the order of the dispersed pieces.

The issuing server 120 recovers the third distributed fragment from the second distributed fragment (C2) and the issuer verification value (IV) using a secret recovery algorithm corresponding to the secret distribution algorithm as in the example of Equation 7 below. A restored third dispersion fragment (C3') is created (318).

[Equation 7]

C3' = SR(S, C2)

Here, C3' is the recovered third distributed fragment, S is the secret data, C2 is the second distributed fragment, and SR() is the secret recovery algorithm.

The issuance server 120 generates a temporary issuer verification value (IV') using the secret data (S) and the restored third distributed piece (C3'), and the temporary issuer verification value (IV') and the issuer verification value ( IV) is matched to verify the issuer verification value (IV) (320). That is, if the temporary issuer verification value (IV') and the issuer verification value (IV) match, it is determined that the verification was successful, and if the temporary issuer verification value (IV') and the issuer verification value (IV) do not match, verification judge you to have failed

In step 320, the issuing server 120 may generate a temporary issuer verification value (IV') by concatenating the secret data and the recovered third distributed fragment (C3') and hashing them as in the example of Equation 8 below. there is.

[Equation 8]

IV == Hash(S||C3')

Here, IV is the issuer verification value, S is the secret data, C3' is the third distributed fragment recovered, and Hash() is the hash function.

The issuance server 120 generates a verification value (V) using the restored third distributed piece (C3') when the temporary issuer verification value (IV') and the issuer verification value (IV) are identical, and the verification value ( V) and the second dispersion piece C2 are stored (322). At this time, the issuing server 120 deletes the secret data S received from the user terminal 110 when storing the second distributed piece C2 and the verification value V.

In step 322, the issuing server 120 may generate a verification value (V) by hashing the recovered third distributed fragment (C3') as in the example of Equation 9 below.

[Equation 9]

V=Hash(C3')

Here, V is a verification value, C3' is a restored third distributed fragment, and Hash() is a hash function.

The issuing server 120 transmits the verification value (V) to the user terminal 110 (324).

Upon receiving the verification value V, the user terminal 110 generates a certificate VC including the first distributed fragment C1 and the verification value V (326).

In step 326, the user terminal 110 digitally signs the first distributed fragment C1 and the verification value V with the signature of the user of the user terminal 110, as in the example of Equation 3 described above, and obtains a certificate (VC). ) can be created.

However, the user's signature used for Sign() in <Equation 5> can be generated by the user based on a decentralized identifier (DID) or public key infrastructure (PKI).

On the other hand, when the user terminal 110 receives the certificate (VC), the secret data (S) can be deleted for security. Secret data can be recovered by performing steps 416 to 428.

4 is a flowchart illustrating a process of transmitting confidential data in a data transmission system according to an embodiment of the present invention.

Referring to FIG. 4 , the user terminal 110 digitally signs the certificate with the user's signature and generates a signed certificate as shown in Equation 10 below (410).

[Equation 10]

VP = Sign(VC)

Here, VP is a signed certificate, VC is a certificate, and Sign() is a digital signature.

At this time, the user's signature used in Sign() may be generated by the user based on a decentralized identifier (DID) or public key infrastructure (PKI).

The user terminal 110 transmits the signed certificate to the verification terminal 130 (412).

The verification terminal 130 verifies the signed certificate and obtains the certificate (414).

In step 414, the verification terminal 130 may verify the signed certificate by checking whether the signed certificate is electronically signed with the signature of the user of the user terminal 110.

At this time, since the certificate included in the signed certificate is digitally signed with the user's signature when generated by the user terminal 110 and digitally signed with the signature of the issuing server 120 when generated by the issuing server 120, A certificate can be verified using the signature of the subject that created the certificate.

The verification terminal 130 extracts the first distributed fragment C1 and the verification value V included in the certificate (416).

The verification terminal 130 transmits the verification value (V) to the issuing server 120 and requests a distributed piece required for recovery of the secret data (S).

When the issuing server 120 receives a request for a distributed piece, it checks whether the verification value V stored in the issuing server 120 and the verification value V received from the verification terminal 130 match, and sends the issuing server 120 When the stored verification value (V) and the verification value (V) received from the verification terminal 130 match, the second distributed fragment C2 stored in the issuing server 120 is retrieved (420), and the stored second distributed fragment (C2) is transmitted to the verification terminal 130 (422).

Meanwhile, the issuing server 120 may perform separate authentication for the verification terminal 130 before step 422 to safely deliver the distributed fragments. At this time, the authentication method may use a known authentication method.

The verification terminal 130 uses the secret recovery algorithm (SR) corresponding to the secret distribution algorithm (SS) to obtain secret data from the first distributed fragment (C1) and the second distributed fragment (C2) received from the issuing server 120. (S) is recovered to generate the recovered secret data (S') (424).

The verification terminal 130 recovers the third distributed fragment from the recovered secret data S' and the first distributed fragment C1 by using the secret recovery algorithm (SR), and obtains the recovered third distributed fragment C3'. Create (426).

The verification terminal 130 generates a temporary verification value (V') using the restored third distributed fragment (C3'), and the temporary verification value (V') is a verification value (V) included in the certificate (VC) If it matches, it is confirmed that the recovered secret data (S') is the same as the secret data (S) (428). In step 428, the verification terminal 130 may generate a temporary verification value V' by hashing the restored third distributed fragment C3'.

The secret distribution algorithm (SS) and the secret recovery algorithm (SR) of the present invention can be applied using the Shamir Secret Sharing technique, and the secret distribution algorithm (SS) to which the Shamir secret sharing technique is applied and the secret recovery algorithm ( SR) is as follows.

Secret distribution algorithm (SS) can generate n number of distributed pieces of secret data in the following way.

First, as in the example of Equation 11 below, a t-order random polynomial f(x) is generated.

[Equation 11]

here uses the secret data (S), and the rest is randomly generated.

second polynomial By substituting from 1 to n in , n distributed pieces are created.

The dispersion pieces (c1, c2, ??, cn) can be expressed as points as in the example of Equation 12 below.

[Equation 12]

c1 = (1, f(1)), c2 = (2, f(2)), ?? , cn = (n, f(n))

The secret recovery algorithm (SR) can recover the secret data (S) with t+1 distributed pieces in the following way.

First, as in the example of Equation 13 below, t + 1 points Recover f(x) from , using Lagrangian interpolation.

[Equation 13]

Second, if f(0) is calculated from the recovered function f(x), the secret data (S) is obtained.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer readable medium. The computer readable medium may store program instructions, data files, data structures, etc. alone or in combination. Program commands recorded on the medium may be specially designed and configured for the embodiment or may be known and usable to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. - includes hardware devices specially configured to store and execute program instructions, such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter, as well as machine language codes such as those produced by a compiler. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

Software may include a computer program, code, instructions, or a combination of one or more of the foregoing, which configures a processing device to operate as desired or processes independently or collectively. The device can be commanded. Software and/or data may be any tangible machine, component, physical device, virtual equipment, computer storage medium or device, intended to be interpreted by or provide instructions or data to a processing device. , or may be permanently or temporarily embodied in a transmitted signal wave. Software may be distributed on networked computer systems and stored or executed in a distributed manner. Software and data may be stored on one or more computer readable media.

As described above, although the embodiments have been described with limited drawings, those skilled in the art can apply various technical modifications and variations based on the above. For example, the described techniques may be performed in an order different from the method described, and/or components of the described system, structure, device, circuit, etc. may be combined or combined in a different form than the method described, or other components may be used. Or even if it is replaced or substituted by equivalents, appropriate results can be achieved.

Therefore, other implementations, other embodiments, and equivalents of the claims are within the scope of the following claims.

Claims (15)

Transmitting secret data from the user terminal to the issuing server;
requesting certificate issuance from the user terminal to the issuing server;
distributing the secret data into a plurality of pieces using a cryptographic secret distribution algorithm in the issuing server;
selecting one of the pieces distributed by the issuing server as a third distribution piece and generating a verification value with the third distribution piece;
selecting, in the issuing server, one of the distributed pieces except for the third distribution piece as a first distribution piece, and generating a certificate including the first distribution piece and the verification value;
selecting, in the issuing server, other than the first distribution pieces and the third distribution pieces from among the distributed pieces as second distribution pieces, and storing the second distribution pieces and the verification value; and
Transmitting the certificate from the issuing server to the user terminal
Data transmission method using secret distribution comprising a.
According to claim 1,
The step of distributing the secret data into a plurality of pieces using a cryptographic secret distribution algorithm in the issuing server,
Distributing the secret data into a plurality of pieces using the secret distribution algorithm defined in the Shamir Secret Sharing technique
Data transmission method using secret distribution.
According to claim 1,
The step of generating the verification value is,
Generating the verification value by hashing the third distributed fragment
Data transmission method using secret distribution.
According to claim 1,
Generating a certificate including the first distributed fragment and the verification value,
Generating the certificate by digitally signing the first distributed fragment and the verification value with the signature of the issuing server
Data transmission method using secret distribution.
According to claim 1,
generating a signed certificate by digitally signing the certificate in the user terminal;
transmitting the signed certificate from the user terminal to a verification terminal;
verifying the signed certificate at the verification terminal and obtaining the certificate;
extracting the first distributed fragment and the verification value included in the certificate in the verification terminal;
transmitting the verification value from the verification terminal to the issuing server and requesting a distributed fragment required for recovery of the secret data;
checking whether the verification value stored in the issuing server and the verification value received from the verification terminal match when the issuing server receives a request for distributed fragments;
in the issuing server, when the verification value stored in the issuing server and the verification value received from the verification terminal match, searching for the second distributed fragment stored in the issuing server and transmitting the same to the verification terminal;
generating recovered secret data by recovering secret data from the first distributed fragment and the second distributed fragment received from the issuing server using a secret recovery algorithm corresponding to the secret distribution algorithm in the verification terminal;
generating a recovered third distributed fragment by recovering a third distributed fragment from the recovered secret data and the first distributed fragment using the secret recovery algorithm in the verification terminal; and
The verification terminal generates a temporary verification value using the recovered third distributed fragment, and if the temporary verification value matches the verification value included in the certificate, it is confirmed that the recovered secret data is the same as the secret data. step to do
Data transmission method using secret distribution further comprising a.
According to claim 5,
The step of verifying the signed certificate in the verification terminal and obtaining the certificate,
Verifying whether the signed certificate is electronically signed with the signature of the user of the user terminal, and confirming and verifying whether the certificate included in the signed certificate is digitally signed with the signature of the issuing server
Data transmission method using secret distribution.
According to claim 5,
The verification terminal generates a temporary verification value using the recovered third distributed fragment, and if the temporary verification value matches the verification value included in the certificate, it is confirmed that the recovered secret data is the same as the secret data. The steps are,
Generating the temporary verification value by hashing the recovered third distributed fragment
Data transmission method using secret distribution.
Transmitting secret data from the user terminal to the issuing server;
distributing the secret data into a plurality of pieces using a cryptographic secret distribution algorithm in the user terminal;
selecting one of the fragments distributed in the user terminal as a third distributed fragment and generating an issuer verification value using the third distributed fragment and the secret data;
selecting a first distributed fragment to be included in a certificate from among the distributed fragments in the user terminal;
The user terminal selects remaining pieces other than the first distributed piece and the third distributed piece from among the distributed pieces as a second distributed piece, and transmits the second distributed piece and the issuer verification value to the issuing server. step;
generating a recovered third distribution fragment by recovering a third distribution fragment from the second distribution fragment and the issuer verification value by using a secret recovery algorithm corresponding to the secret distribution algorithm in the issuing server;
generating a temporary issuer verification value using the secret data and the restored third distributed fragment in the issuing server, and verifying whether the temporary issuer verification value and the issuer verification value match;
generating a verification value using the restored third distribution fragment and storing the verification value and a second distribution fragment when the temporary issuer verification value and the issuer verification value coincide with each other in the issuing server;
transmitting the verification value from the issuing server to the user terminal; and
generating a certificate including the first distributed fragment and the verification value when the user terminal receives the verification value;
Data transmission method using secret distribution comprising a.
According to claim 8,
The step of selecting one of the fragments distributed in the user terminal as a third distributed fragment and generating an issuer verification value using the third distributed fragment and the secret data,
Concatenating and hashing the secret data and the third distributed fragment to generate the issuer verification value
Data transmission method using secret distribution.
According to claim 8,
The step of generating a temporary issuer verification value using the secret data and the recovered third distributed fragment in the issuing server, and checking whether the temporary issuer verification value and the issuer verification value match,
generating the temporary issuer verification value by concatenating and hashing the secret data and the recovered third distributed fragment;
Data transmission method using secret distribution.
According to claim 8,
In the issuing server, if the temporary issuer verification value and the issuer verification value match, generating a verification value using the restored third distribution fragment and storing the verification value and the second distribution fragment,
Generating the verification value by hashing the recovered third distributed fragment
Data transmission method using secret distribution.
According to claim 8,
When the user terminal receives the verification value, generating a certificate including the first distributed fragment and the verification value,
Generating the certificate by digitally signing the first distributed fragment and the verification value with the signature of the user of the user terminal
Data transmission method using secret distribution.
According to claim 8,
generating a signed certificate by digitally signing the certificate in the user terminal;
transmitting the signed certificate from the user terminal to a verification terminal;
verifying the signed certificate at the verification terminal and obtaining the certificate;
extracting the first distributed fragment and the verification value included in the certificate in the verification terminal;
transmitting the verification value from the verification terminal to the issuing server and requesting a distributed fragment required for recovery of the secret data;
checking whether the verification value stored in the issuing server and the verification value received from the verification terminal match when the issuing server receives a request for distributed fragments;
in the issuing server, when the verification value stored in the issuing server and the verification value received from the verification terminal match, searching for the second distributed fragment stored in the issuing server and transmitting the same to the verification terminal;
generating recovered secret data by recovering secret data from the first distributed fragment and the second distributed fragment received from the issuing server using a secret recovery algorithm corresponding to the secret distribution algorithm in the verification terminal;
generating a recovered third distributed fragment by recovering a third distributed fragment from the recovered secret data and the first distributed fragment using the secret recovery algorithm in the verification terminal; and
The verification terminal generates a temporary verification value using the recovered third distributed fragment, and if the temporary verification value matches the verification value included in the certificate, it is confirmed that the recovered secret data is the same as the secret data. step to do
Data transmission method using secret distribution further comprising a.
According to claim 13,
The step of verifying the signed certificate in the verification terminal and obtaining the certificate,
Verifying and verifying whether the signed certificate is electronically signed with the signature of the user of the user terminal
Data transmission method using secret distribution.
According to claim 13,
The verification terminal generates a temporary verification value using the recovered third distributed fragment, and if the temporary verification value matches the verification value included in the certificate, it is confirmed that the recovered secret data is the same as the secret data. The steps are,
Generating the temporary verification value by hashing the recovered third distributed fragment
Data transmission method using secret distribution.

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