KR20200091112A - Method for sharing information using blockchain technology - Google Patents

Abstract

The present invention relates to an information sharing method using blockchain technology for safer information sharing. The method includes: a step in which an information generation node as one of M nodes generates information A-encrypted cryptogram A, N distributed decryption keys (N is an integer equal to or less than M) for decrypting cryptogram A, and block A including cryptogram A; a step in which the information generation node transmits block A to the M nodes; a step in which the information generation node transmits the N distributed decryption keys one by one to N decryption key storage nodes constituting the M nodes; a step in which each of the M nodes generates and stores a new blockchain by connection between block A and a pre-stored blockchain; a step in which a decryption request node as one of the M nodes generates a decryption request signal and transmits the signal to the decryption key storage nodes; a step in which each of the decryption key storage nodes determines whether to transmit the distributed decryption key stored in itself by using the decryption request signal and transmits the key to the decryption request node; and a step in which the decryption request node decrypts cryptogram A by using the distributed decryption key transmitted from the decryption storage nodes. As described above, cryptogram A can be decrypted only after the decryption request node obtains consent of the decryption storage nodes and obtains a predetermined number of distributed decryption keys. Accordingly, the security of information A can be strengthened.

Description

Information sharing method using blockchain technology{METHOD FOR SHARING INFORMATION USING BLOCKCHAIN TECHNOLOGY}

The present invention relates to an information sharing method, and more particularly, to an information sharing method capable of sharing information generated in an arbitrary server with another server using a blockchain technology.

In the blockchain platform, the members (nodes) participating in the system distribute and store data in their respective blocks (servers), making forgery and alteration of data virtually impossible, and members can retain their distributed information, and a separate central server The manager of has also had unnecessary advantages.

These blockchain platforms are generally applied to the trading of cryptocurrencies such as Bitcoin and Ethereum, but recently they are also applied to securely sharing other information. For example, Korean Patent Registration No. 10-1893729 discloses a method for sharing data based on multiple blockchains.

Meanwhile, various types of servers exist in each country or region, and these servers may be connected by a network to share information. At this time, the servers may safely share information generated by each in the blockchain platform.

Specifically, for example, a server located in an arbitrary region may generate and collect information collected by itself as a block, then propagate it to servers in other regions and store it. In this case, the information propagated to other servers may consist of only information of contents that can be shared with servers in other regions, but in some cases, information about local interests, personal interests, or personal privacy may also be included. Therefore, when sharing information on a blockchain platform, it is necessary to improve the security of some information.

Therefore, the present invention is intended to solve this problem, and the problem to be solved by the present invention is to provide an information sharing method capable of more securely sharing information using a blockchain technology.

In the information sharing method according to an embodiment of the present invention, any node among the M nodes (hereinafter referred to as an'information generating node') is encrypted cipher A where information A is encrypted, and N distributions for decrypting the ciphertext A. Generating a block A including decryption keys (where N is an integer equal to or less than M) and the ciphertext A; The information generating node transmitting the block A to the M nodes; Transmitting, by the information generating node, the N distributed decryption keys to N nodes among the M nodes (hereinafter referred to as'decryption key storage nodes'); Each of the M nodes connecting the block A to a pre-stored blockchain to generate and store a new blockchain; A step in which any of the M nodes (hereinafter referred to as a'decryption request node') generates a decryption request signal and transmits it to the decryption key storage nodes; Each of the decryption key storage nodes using the decryption request signal, determining whether to transmit the distributed decryption key stored therein and transmitting it to the decryption request node; And decrypting the ciphertext A by the decryption request node using the distributed decryption key received from the decryption storage nodes.

The information generating node generating the ciphertext A, the N distributed decryption keys, and the block A includes: the information generating node generating the information A; Generating, by the information generating node, the information A by encrypting the information A; Generating, by the information generating node, a decryption key A for decrypting the ciphertext A; Generating, by the information generating node, the N distributed decryption keys using the decryption key A; And generating, by the information generating node, the block A including the ciphertext A.

Each of the decryption key storage nodes determines whether to transmit the distributed decryption key stored therein and transmits it to the decryption request node. Each decryption key storage node requests the decryption using the decryption request signal. Determining whether to allow decryption according to the node's decryption request; And among the decryption key storage nodes, a node determined to allow decryption at the decryption request node (hereinafter referred to as a'decryption grant node') is the distributed decryption key stored by itself among the N distributed decryption keys. It may include transmitting to the decryption request node.

The decryption request node decrypting the ciphertext A may include determining whether the decryption request node can decrypt the ciphertext A using a distributed decryption key transmitted from the decryption granting node; And when the decryption request node determines that decryption of the ciphertext A is possible, decrypting the ciphertext A to extract the information A.

The decryption key storage nodes may include N-1 nodes among the M nodes and the information generation node. Alternatively, the decryption key storage nodes may include N nodes excluding the information generating node among the M nodes.

The decryption request node may be one of the decryption key storage nodes. At this time, in the step of transmitting the decryption request signal to the decryption key storage nodes by the decryption request node, the decryption request node sends the decryption key storage nodes to N-1 nodes other than the decryption request node among the decryption key storage nodes. A decryption request signal can be transmitted. In addition, in the step of determining whether the decryption request node can decrypt the ciphertext A, the decryption request node uses the distributed decryption key stored by the decryption request node and the distributed decryption key received from the decryption granting node. It is possible to determine whether decoding is possible.

Alternatively, the decryption request node may be a node not included in the decryption key storage nodes among the M nodes.

In the step of determining whether the decryption request node can decrypt the ciphertext A, it is determined that decryption of the ciphertext A is possible when the decryption request node receives K or more distributed decryption keys from the decryption key storage nodes. And, when receiving less than K distributed decryption keys from the decryption key storage nodes, it can be determined that decryption of the ciphertext A is impossible.

In the step of determining whether the decryption request node can decrypt the ciphertext A, when the decryption request node receives a distributed decryption key from at least 1/2 of the decryption key storage nodes, decryption of the ciphertext A If it is determined that it is possible, and if a distributed decryption key is received from nodes less than 1/2 of the decryption key storage nodes, it may be determined that decryption of the ciphertext A is impossible.

As described above, according to the information sharing method according to the present invention, any node encrypts the information A owned by itself and generates the ciphertext A, and then transmits it to the M nodes in a block form and can decrypt the ciphertext A. After generating the N distributed decryption keys and transmitting them to the N nodes one by one, the node that wants to extract the information A by decrypting the ciphertext A among the M nodes obtains consent from the N nodes Among the N distributed decryption keys, K or more distributed decryption keys must be obtained. As a result, the security of the information A can be further improved.

1 is a conceptual diagram illustrating an information sharing system according to an embodiment of the present invention.
FIG. 2 is a conceptual diagram illustrating a process of generating ciphertext A, N distributed decryption keys and block A among information sharing methods by the information sharing system of FIG. 1.
FIG. 3 is a conceptual diagram illustrating a process of transmitting the block A and N distributed decryption keys generated in the process of FIG. 2.
FIG. 4 is a conceptual diagram illustrating a process of generating a new blockchain using block A transmitted in the process of FIG. 3.
5 is a conceptual diagram illustrating a new blockchain created in the process of FIG. 4 as an example.
6 is a conceptual diagram illustrating a process of a decryption request node transmitting a decryption request signal among the information sharing methods by the information sharing system of FIG. 1.
7 is a conceptual diagram illustrating an example of a process of decrypting a ciphertext A by a decryption request node among information sharing methods by the information sharing system of FIG. 1.
8 is a conceptual diagram illustrating another example of a process of decrypting a ciphertext A by a decryption request node among information sharing methods by the information sharing system of FIG. 1.

The present invention may be variously modified and may have various forms, and specific embodiments will be illustrated in the drawings and described in detail in the text.

However, this is not intended to limit the present invention to specific disclosure forms, and it should be understood that all modifications, equivalents, and substitutes included in the spirit and scope of the present invention are included. Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from other components. For example, the first component may be referred to as a second component without departing from the scope of the present invention, and similarly, the second component may also be referred to as a first component.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "include" or "have" are intended to indicate the presence of a feature, number, step, action, component, part, or combination thereof described in the specification, but one or more other features or It should be understood that the presence or addition possibilities of numbers, steps, actions, components, parts or combinations thereof are not excluded in advance.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

1 is a conceptual diagram illustrating an information sharing system according to an embodiment of the present invention.

Referring to FIG. 1, the information sharing system according to the present embodiment includes M nodes 10 connected to each other through a network (where M is an integer of 2 or more). In this case, the M nodes 10 may be computer systems connected to each other through a network, for example, server systems.

In this embodiment, each of the M nodes 10 may perform a block generation function capable of generating and sharing a block, and a block verification function capable of feedback after verifying the transmitted block. .

Meanwhile, among the M nodes 10, N nodes (hereinafter referred to as'decryption key storage nodes') for storing and storing a decryption key may be included (wherein N is 2 or more and M Less than or equal to).

Hereinafter, an information sharing method will be described in detail by using the information sharing system described above.

FIG. 2 is a conceptual diagram illustrating a process of generating ciphertext A, N distributed decryption keys and block A among information sharing methods by the information sharing system of FIG. 1.

Referring to FIG. 2, in the information sharing method according to the present embodiment, any node among the M nodes (hereinafter referred to as an'information generating node'), for example, node D1 is encrypted cipher text A in which information A is encrypted. , Block A including N distributed decryption keys for decrypting the ciphertext A and the ciphertext A may be generated.

Specifically, after the information generating node generates the information A and decides to safely share the information A, the ciphertext A can be generated by encrypting the information A. At this time, the information generating node may generate a decryption key A for decrypting the ciphertext A together. Thereafter, the information generating node may generate the N distributed decryption keys using the decryption key A. For example, the information generation node may generate the N distributed decryption keys by dividing the decryption key A into N pieces by a (K, N) threshold secret distribution method. Here, K distributed decryption keys among the N distributed decryption keys must be collected to restore the decryption key A. In this embodiment, the (K, N) threshold secret distribution method may be a secret distribution method by BLS signature. Thereafter, the information generating node may generate the block A including the ciphertext A. At this time, the block A includes the ciphertext A, and may include other types of information.

In this embodiment, the block A may include a block header and a block body. The block header may include a corresponding block representative value that can represent the corresponding block, and a previous block representative value that can represent the previous block in which the corresponding block was immediately generated. For example, the corresponding block representative value may be a corresponding block hash value generated through a hash function, and the previous block representative value may be a previous block hash value generated through a hash function. The block body includes the ciphertext A, and may include other types of information.

FIG. 3 is a conceptual diagram illustrating a process of transmitting the block A and N distributed decryption keys generated in the process of FIG. 2, and FIG. 4 is a method of generating a new blockchain using block A transmitted in the process of FIG. 3 It is a conceptual diagram for explaining the process, and FIG. 5 is a conceptual diagram illustrating a new blockchain created in the process of FIG. 4 as an example.

3, 4 and 5, the information generating node may then transmit the block A to the M nodes. Specifically, when the information generating node transmits the block A to the M nodes, the M nodes perform verification on the received block A to generate a verification result, and then generate the verification result. The information generating node may be fed back. Here, since the information generating node is included in the M nodes, the information generating node can self-verify the block A and feed it back. Thereafter, the information generation node may determine whether the verification of the block A has passed using the verification results, and if the determination result is verification verification, the block A may be transmitted to the M nodes.

At the same time as the transmission of the block A or after the transmission of the block A, the information generating node has the N distributed decryption keys N nodes among the M nodes (hereinafter referred to as'decryption key storage nodes'). Can be sent one by one. For example, the information generating node may transmit five distributed decryption keys to N decryption key storage nodes one by one.

In this embodiment, the information generating node may be included in the N distributed decryption keys. That is, the decryption key storage nodes may include N-1 nodes among the M nodes and the information generation node. For example, as shown in FIG. 3, among the N distributed decryption keys, the distributed decryption key K1 is stored in the information generating node, and among the N distributed decryption keys, the distributed decryption key K2 to the distributed decryption key K5 are nodes N2 to nodes. It can be transmitted and stored one by one in N5.

Alternatively, the information generating node may not be included in the N distributed decryption keys. That is, the decryption key storage nodes may include N nodes excluding the information generating node among the M nodes.

Subsequently, each of the M nodes may connect the block A to a pre-stored blockchain to generate and store a new blockchain. As a result, all of the M nodes may be storing the new blockchain.

6 is a conceptual diagram illustrating a process of a decryption request node transmitting a decryption request signal among the information sharing methods by the information sharing system of FIG. 1.

Referring to FIG. 6, thereafter, any of the M nodes (hereinafter referred to as a'decryption request node') may generate a decryption request signal and transmit it to the decryption key storage nodes.

In this embodiment, the decryption request node may be a node not included in the decryption key storage nodes among the M nodes, for example, node N6. For example, when the decryption request node is a node N6 as shown in FIG. 6, when the node N6 determines that decryption of the ciphertext A included in the block A is necessary, the node N1 is generated after generating the decryption request signal. , Node N2, node N3, node N4 and node N5, respectively.

Alternatively, the decryption request node may be one of the decryption key storage nodes. That is, the decryption request node may transmit the decryption request signal to N-1 nodes other than the decryption request node among the decryption key storage nodes. For example, when the decryption request node is a node N2, if the node N2 determines that decryption of the ciphertext A included in the block A is necessary, the node N1, node N3, node after generating the decryption request signal N4 and node N5, respectively.

7 is a conceptual diagram illustrating an example of a process of decrypting a ciphertext A by a decryption request node among the information sharing methods by the information sharing system of FIG. 1, and FIG. 8 is a method of sharing information by the information sharing system of FIG. 1 It is a conceptual diagram for explaining another example of a process in which the decryption request node decrypts the ciphertext A.

7 and 8, thereafter, each of the decryption key storage nodes may determine whether to transmit the distributed decryption key that it stores by using the decryption request signal and transmit it to the decryption request node.

In detail, each of the decryption key storage nodes can determine whether or not to allow decryption according to the decryption request of the decryption request node by using the decryption request signal received from the decryption request node. For example, when the decryption request signal includes attribute information of the decryption request node, information about the purpose, purpose, and urgency of use of the information A, each of the decryption key storage nodes includes the decryption request node. It is possible to determine whether or not to allow decryption according to the decryption request by determining whether the information A has an attribute that can be used, whether the purpose and purpose of using the information A are appropriate, and whether the information A is in an urgent situation. have.

Then, among the decryption key storage nodes, a node determined to allow decryption at the decryption request node (hereinafter referred to as a'decryption grant node') uses the distributed decryption key stored by itself among the N distributed decryption keys. It can be transmitted to the decryption request node. On the other hand, among the decryption key storage nodes, the node determined to disallow decryption at the decryption request node may transmit an unauthorized decryption message to the decryption request node instead of transmitting the distributed decryption key stored therein.

Subsequently, the decryption request node may decrypt the ciphertext A using the distributed decryption key transmitted from the decryption storage nodes.

In detail, the decryption request node can determine whether the ciphertext A can be decrypted using the distributed decryption key transmitted from the decryption granting node. For example, if the decryption request node does not have a distributed decryption key stored by the decryption request node as shown in FIG. 7, it is determined whether the decryption of the ciphertext A is possible using only the distributed decryption key transmitted from the decryption granting node. Can. On the other hand, when the decryption request node has a distributed decryption key that it stores, as shown in FIG. 8, it uses the distributed decryption key that it stores and the distributed decryption key transmitted from the decryption permission node together, thereby encrypting the ciphertext A. It is possible to determine whether decoding is possible.

In the present embodiment, when the decryption key A is divided into N by the (K, N) threshold secret distribution method and the N distributed decryption keys are generated, the decryption request node has K from the decryption key storage nodes. When receiving the above distributed decryption keys, it is determined that decryption of the ciphertext A is possible, and when less than K distributed decryption keys are received from the decryption key storage nodes, it can be determined that decryption of the ciphertext A is impossible. have. For example, K may be a rounded integer of N/2.

Thereafter, when the decryption request node determines that decryption of the ciphertext A is possible, the ciphertext A may be decrypted to extract the information A.

As described above, according to the present embodiment, the information storage node encrypts the information A owned by the information storage node to generate the ciphertext A, and then transmits it to the M nodes in a block form, and can decrypt the ciphertext A. After generating N distributed decryption keys and transmitting them to N nodes one by one, a node that wants to extract the information A by decrypting the ciphertext A among the M nodes obtains consent from the N nodes Of the N distributed decryption keys, more than K distributed decryption keys must be obtained. As a result, the security of the information A can be further improved.

In the detailed description of the present invention described above, it has been described with reference to preferred embodiments of the present invention, but those skilled in the art or those skilled in the art will appreciate the spirit of the present invention as set forth in the claims below. And it will be understood that various modifications and changes can be made to the present invention without departing from the scope of the technology.

10: node

Claims (12)

Any of the M nodes (hereinafter referred to as an'information generating node') is a ciphertext A with information A encrypted, and N distributed decryption keys for decrypting the ciphertext A (where N is an integer equal to or less than M) And generating block A including the ciphertext A.
The information generating node transmitting the block A to the M nodes;
Transmitting, by the information generating node, the N distributed decryption keys to N nodes among the M nodes (hereinafter referred to as'decryption key storage nodes');
Each of the M nodes connecting the block A to a pre-stored blockchain to generate and store a new blockchain;
A step in which any of the M nodes (hereinafter referred to as a'decryption request node') generates a decryption request signal and transmits it to the decryption key storage nodes;
Each of the decryption key storage nodes using the decryption request signal, determining whether to transmit the distributed decryption key stored therein and transmitting it to the decryption request node; And
And decrypting the ciphertext A by the decryption request node using a distributed decryption key received from the decryption storage nodes. According to claim 1,
The step of generating the ciphertext A, the N distributed decryption keys, and the block A by the information generating node is
The information generating node generating the information A;
Generating, by the information generating node, the information A by encrypting the information A;
Generating, by the information generating node, a decryption key A for decrypting the ciphertext A;
The information generating node generating the N distributed decryption keys using the decryption key A; And
And generating, by the information generating node, the block A including the ciphertext A. According to claim 1,
The step of determining whether each of the decryption key storage nodes transmits the distributed decryption key stored in the decryption key and transmitting the decryption key to the decryption request node is performed.
Determining whether each of the decryption key storage nodes grants decryption according to a decryption request of the decryption request node using the decryption request signal; And
Among the decryption key storage nodes, a node determined to allow decryption at the decryption request node (hereinafter referred to as a'decryption grant node') decrypts the decryption key stored by itself among the N distributed decryption keys. And transmitting to the requesting node. According to claim 3,
The step of decrypting the ciphertext A by the decryption request node
Determining whether the decryption request node can decrypt the ciphertext A by using a distributed decryption key transmitted from the decryption granting node; And
And if the decryption request node determines that decryption of the ciphertext A is possible, decrypting the ciphertext A to extract the information A. According to claim 4,
The decryption key storage nodes are
And N-1 nodes among the M nodes, and the information generating node. According to claim 4,
The decryption key storage nodes are
Information sharing method characterized in that it comprises N nodes of the M nodes excluding the information generation node. According to claim 4,
And the decryption request node is one of the decryption key storage nodes. The method of claim 7,
In the decryption request node transmitting the decryption request signal to the decryption key storage nodes,
And the decryption request node transmits the decryption request signal to N-1 nodes other than the decryption request node among the decryption key storage nodes. The method of claim 8,
In the step of determining whether the decryption request node can decrypt the ciphertext A,
The decryption request node determines whether it is possible to decrypt the ciphertext A by using the distributed decryption key stored in the decryption key received from the decryption grant node and its own. According to claim 4,
And the decryption request node is a node not included in the decryption key storage nodes among the M nodes. According to claim 4,
In the step of determining whether the decryption request node can decrypt the ciphertext A,
When the decryption request node receives more than K distributed decryption keys from the decryption key storage nodes, it is determined that decryption of the ciphertext A is possible, and less than K distributed decryption keys are received from the decryption key storage nodes. If it does, it is determined that decryption of the ciphertext A is impossible. The method of claim 11,
In the step of determining whether the decryption request node can decrypt the ciphertext A,
When the decryption request node receives a distributed decryption key from at least 1/2 of the decryption key storage nodes, it is determined that decryption of the ciphertext A is possible, and less than 1/2 of the decryption key storage nodes When receiving a distributed decryption key from nodes, it is determined that decryption of the ciphertext A is impossible.

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