WO2022177204A1

WO2022177204A1 - Did-based decentralized system for storing and sharing user data

Info

Publication number: WO2022177204A1
Application number: PCT/KR2022/001539
Authority: WO
Inventors: 이정륜; 한황제; 윤태연
Original assignee: 주식회사 블록체인기술연구소
Priority date: 2021-02-22
Filing date: 2022-01-28
Publication date: 2022-08-25
Also published as: KR20220120062A; KR102465467B1; KR102483369B1; KR20220143625A

Abstract

A DID-based decentralized system for storing and sharing user data is provided. The system for storing and sharing user data comprises: a data sharing brokerage server; a first user terminal; and a storage device, wherein the data sharing brokerage server links with a blockchain network and inquires about DID information registered in the blockchain network, the first user terminal registers or deletes DID information for establishing an access right to user data in a DID document of the data sharing brokerage server which is registered in the blockchain network, and transmits encrypted user data, key index information, and initial vector information to the data sharing brokerage server, and the storage device receives, from the data sharing brokerage server, and stores the encrypted user data, the key index information, and the initial vector information.

Description

DID-based decentralized user data storage and sharing system

The present invention relates to a DID-based decentralized user data storage and sharing system. More specifically, users who can enhance security through a decentralized private key recovery service, improve key backup and management issues for the vast amount of key pairs required in a DID environment, and share users’ sensitive data It relates to data storage and sharing systems.

Blockchain refers to a data distribution processing technology that distributes and stores all data that is managed by all users participating in the network. It is also called 'Distributed Ledger Technology (DLT)' or 'Public Transaction Ledger' in that the ledger containing transaction information is not owned by the transaction subject or a specific institution, but is a technology shared by all network participants. Blockchain is a name given to the fact that blocks containing transaction contents are linked like a chain. This block chain is a technology to prevent hacking such as forgery and forgery of transaction contents, and it uses a method to prevent data forgery by sending transaction details to all users participating in the transaction and collating them for each transaction.

Blockchain is a core concept of decentralization, which aims for P2P (Peer to Peer) transactions, away from the existing financial system that secures and manages all transactions in financial institutions. P2P refers to a communication network that connects personal computers without a server or client, and each connected computer acts as a server and client and shares information. A trust relationship is formed digitally through a method in which multiple nodes share and verify the same data. This environment makes it possible to realize smart contracts that can conveniently conclude and modify contracts with P2P without intermediaries.

In the existing financial system, financial companies have kept transaction records in a central server, whereas in a blockchain based on the P2P method, transaction information is stored in blocks and connected in turn, and it is shared by all participants to prevent forgery and falsification of transaction information. can

The technical problem to be solved by the present invention is to provide a user data storage and sharing system that can improve the problem of managing a vast amount of private and symmetric keys for data sharing in a blockchain network.

However, the technical problems to be solved by the present invention are not limited to the above problems, and may be variously expanded without departing from the technical spirit and scope of the present invention.

A user data storage and sharing system according to an embodiment of the present invention for solving the above problems is a user data storage and sharing system including a data sharing mediation server, a first user terminal, and a storage device, and interworking with a blockchain network Registers or deletes DID information for setting access rights to user data in the DID document of the data sharing mediation server registered in the blockchain network and the data sharing mediation server registered in the blockchain network to inquire about DID information registered in the blockchain network, , a first user terminal for transmitting encrypted user data, key index information, and initial vector information to the data sharing mediation server, and the encrypted user data from the data sharing mediation server, the key index information, and the and a storage device for receiving and storing initial vector information, wherein when a second user terminal different from the first user terminal requests user data of the first user terminal from the data sharing intermediary server, the first user terminal registers the DID information of the second user terminal in the DID document of the data sharing mediation server registered in the blockchain network, and grants the second user terminal access to the user data of the first user terminal do.

In some embodiments according to the present invention, the DID document of the data sharing intermediary server registered in the blockchain network includes a first attribute value and a second attribute value, and the first attribute value is DID information of the data owner terminal Including, the second attribute value may include DID information of the user terminal accessible to the shared data.

In some embodiments according to the present invention, when the second user terminal requests the user data of the first user terminal to the data sharing intermediary server, the first user terminal is, Decrypting user data, generating a shared symmetric key and a random initial vector to be shared with the second user terminal, encrypting the decrypted user data using the shared symmetric key, the generated random initial vector and the The encrypted user data may be transmitted to the second user terminal.

In some embodiments according to the present invention, the data sharing mediation server includes the second user terminal in the value of the second attribute of the DID document of the data sharing mediation server associated with the first user terminal registered in the blockchain network. check whether the DID information is registered, and allow access of the second user terminal when the DID information of the second user terminal is registered in the second attribute value, and the second user terminal, A shared symmetric key may be generated by inquiring DID documents of the first user terminal and the second user terminal, and the encrypted user data may be decrypted using the generated shared symmetric key.

Other specific details of the invention are included in the detailed description and drawings.

According to the present invention, the sender and receiver can safely transmit and receive sensitive data while improving the problem of managing a vast amount of symmetric keys for sensitive data including user personal information in a blockchain network.

In addition, according to the present invention, the sender and the receiver can transmit and receive sensitive data by sharing a secure symmetric key within the blockchain network.

In addition, according to the present invention, with respect to the public and private keys required to generate a symmetric key within the blockchain network, the sender and the receiver can record only the index information of the key used for data sharing at any time. Pairs can be created for easy data sharing.

However, the effects of the present invention are not limited to the above effects, and may be variously expanded without departing from the spirit and scope of the present invention.

1 is a diagram illustrating a distributed processing system using a block chain to which the technical idea according to the present invention can be applied.

2 and 3 are block diagrams showing the connection of blocks used in the block chain system.

4 is a block diagram schematically illustrating a DID-based decentralized user data storage and sharing system according to the present invention.

5 is a block diagram illustrating an operation of storing user data in a system for storing and sharing user data according to an embodiment of the present invention.

6 is a block diagram illustrating an operation of generating and backing up a child key in a key management system included in a user data storage and sharing system according to an embodiment of the present invention.

7 is a diagram exemplarily illustrating a DID generation process of a data sharing intermediary server in a user data storage and sharing system according to an embodiment of the present invention.

8 is a diagram exemplarily illustrating a DID document of a first user terminal in a system for storing and sharing user data according to an embodiment of the present invention.

9 is a diagram exemplarily illustrating a DID document of a data sharing mediation server in a user data storage and sharing system according to an embodiment of the present invention.

10 is a block diagram illustrating an operation of sharing user data in a system for storing and sharing user data according to an embodiment of the present invention.

11 is a diagram exemplarily illustrating a DID document of a second user terminal in a system for storing and sharing user data according to an embodiment of the present invention.

12 is a diagram exemplarily illustrating a DID document of a data sharing mediation server in a user data storage and sharing system according to an embodiment of the present invention.

13 is a diagram exemplarily illustrating a DID document of a first user terminal in a system for storing and sharing user data according to an embodiment of the present invention.

14 is a diagram exemplarily illustrating a DID document of a second user terminal in a system for storing and sharing user data according to an embodiment of the present invention.

15 is a block diagram of a computing device of a node according to an embodiment of the present invention.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be embodied in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims.

The terminology used herein is for the purpose of describing the embodiments, and is not intended to limit the present invention. In this specification, the singular also includes the plural, unless specifically stated otherwise in the phrase. As used herein, “comprises” and/or “comprising” refers to the presence of one or more other components, steps, operations and/or elements mentioned. or addition is not excluded.

Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used with the meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not to be interpreted ideally or excessively unless clearly specifically defined.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. The same reference numerals are used for the same components in the drawings, and repeated descriptions of the same components are omitted.

The existing personal information and authentication information management method is centralized, and there are risks in terms of protection of personal privacy and inconvenience in the management and authentication process for the managed personal information and authentication information. An alternative is needed. Therefore, research on self-sovereign identity service (SSI), which combines block chain and identity authentication, is being conducted at home and abroad, but the existing self-authentication method is done through an accredited certificate issued by a third party. have.

However, the need for DID (Decentralized Identifier) has emerged as questions have been raised as to whether identity authentication is performed through a third party. By utilizing the cryptographic nature of the blockchain, it is possible to prove an individual's identity through a unique Distributed Identifier (DID) that proves himself/herself without the involvement of a central authority. When using DID to prove personal identity, DID registration and digital signature are performed based on the private key, so it is also necessary to safely store the private key.

Currently, the DID service is being developed with a focus on registering personal information that can be disclosed on the block chain and specifying the personal use or scope of use when necessary. However, these services focus only on proof of ownership and prevention of forgery, and it is necessary to store and share sensitive data for individuals based on DID.

Hereinafter, the concept of a DID and a DID document will be described first.

DID means a unique identifier that can prove who you are by CRUD (Create, Read, Update, Delete) of information that can identify an individual centered on the user without a central authority. DID acts as a pointer to the DID document of a blockchain transaction as a single key value. In particular, the DID is an identifier generated based on the user's public key.

The DID document refers to a set necessary for an individual to authenticate himself or herself and prove association with the DID. The object of DID CRUD execution is a DID document, which means information necessary for verification when using the DID service. There are properties such as public key, authentication method, and digital signature value in the data set.

The relationship between DID and DID document is to search for DID in the block chain and create a DID document based on the transaction contents, and the method of reading the DID document based on the DID may be different for each block chain.

In order to share user's sensitive data using DID, a symmetric key is shared between the sender and the receiver in advance, or the data is encrypted with the symmetric key and the symmetric key is encrypted with the public key of the receiver and delivered. In both cases, users have the burden of managing a vast amount of private and symmetric keys. Therefore, in the present invention, the problem of managing a vast amount of keys required for sharing user data is to be improved.

Hereinafter, a distributed processing system using a block chain to which the concept of the present invention can be applied will be described.

Referring to FIG. 1 , a distributed processing system 100 using a block chain is a distributed network system consisting of a plurality of nodes 110-170. The nodes 110 to 170 constituting the distributed network 100 may be electronic devices having computing power, such as computers, mobile terminals, and dedicated electronic devices.

In general, the decentralized network 100 can store and refer to information commonly known to all participating nodes in a connected bundle of blocks called blockchain. The nodes 110-170 can communicate with each other and can be divided into a full node that stores, manages, and propagates the block chain and a light node that can simply participate in transactions. . When referring to a node without a separate description in this specification, it often refers to a full node that participates in a distributed network and performs an operation to create, store, or verify a block chain, but is not limited thereto.

Each block connected to the block chain includes transaction details within a certain period, ie, transactions. The nodes can manage transactions by creating, storing, or verifying the blockchain according to their respective roles.

According to an embodiment, the transaction may represent various types of transactions. In one embodiment, the transaction may correspond to a financial transaction for indicating the ownership status of cryptocurrency and its change. In another embodiment, the transaction may correspond to a physical transaction for indicating the ownership status of the object and its change. In another embodiment, the transaction may correspond to an information sharing process to represent the recording, storage and transfer of information. Nodes performing a transaction in the distributed network 100 may have a private key and a public key pair each cryptographically related.

Referring to FIG. 2 , the block chain 200 is a kind of distributed database of one or more sequentially

connected blocks

210 , 220 , 230 . The block chain 200 is used to store and manage user's transaction details in the block chain system, and each node participating in the network of the block chain system creates a block and connects it to the block chain 200 . 3 shows a limited number of

blocks

210 , 220 , 230 , but the number of blocks that can be included in the block chain is not limited thereto.

Each block included in the block chain 200 may be configured to include a block header 211 and a block body 213 . The block header 211 may include a hash value of the previous block 220 to indicate a connection relationship between blocks. In the process of verifying whether the block chain 200 is valid, the connection relationship in the block header 211 is used. The block body 213 may include data stored and managed in the block 210 , for example, a transaction list or a transaction chain.

Referring to FIG. 3 , the block header 211 may include a hash 2112 of a previous block, a hash 2113 of a current block, and a nonce 2114 . Also, the block header 211 may include a root 2115 indicating a header of a transaction list in a block.

As described above, the blockchain 200 may include one or more connected blocks. The one or more blocks are connected based on a hash value in the block header 211 . The hash value 2112 of the previous block included in the block header 211 is the same as the current hash 2213 included in the previous block 220 as a hash value of the previous block 220 . The one or more blocks are chained by the hash value of the previous block in each block header. Nodes participating in the distributed network verify the validity of a block based on the hash value of the previous block included in the one or more blocks, so it is impossible for a single malicious node to forge or falsify the contents of an already created block do.

The block body 213 may include a transaction list 2131 . The transaction list 2131 is a list of blockchain-based transactions. For example, the transaction list 2131 may include a record of financial transactions made in the blockchain-based financial system. The transaction list 2131 may be expressed in the form of a tree, for example, the amount of money transmitted by user A to user B is recorded in the form of a list, and the storage length in the block is the value of the transaction included in the current block. It can be increased or decreased based on the number.

In addition, the block 210 may include other information 2116 other than the information included in the block header 211 and the block body 213 .

Nodes participating in a decentralized network have the same blockchain, and the same transactions are stored in blocks. A block containing a list of transactions is shared on the network, so all participants can verify it.

Hereinafter, a user data storage and sharing system according to an embodiment of the present invention will be described. The user data storage and sharing method described in the present invention is an algorithm executed in a computing device.

4 is a block diagram schematically illustrating a DID-based decentralized user data storage and sharing system according to the present invention. 5 is a block diagram illustrating an operation of storing user data in a system for storing and sharing user data according to an embodiment of the present invention. 6 is a block diagram illustrating an operation of generating and backing up a child key in a key management system included in a user data storage and sharing system according to an embodiment of the present invention. 7 is a diagram exemplarily illustrating a DID generation process of a data sharing intermediary server in a user data storage and sharing system according to an embodiment of the present invention. 8 is a diagram exemplarily illustrating a DID document of a first user terminal in a system for storing and sharing user data according to an embodiment of the present invention. 9 is a diagram exemplarily illustrating a DID document of a data sharing mediation server in a user data storage and sharing system according to an embodiment of the present invention.

4 to 9 , the user data storage and sharing system 300 according to an embodiment of the present invention includes a data sharing mediation server 310 , a first user terminal 321 , and a storage device 330 . is composed

In the user data storage and sharing system 300 according to an embodiment of the present invention, the data sharing mediation server 310, the first user terminal 321, and the storage device 330 are connected to each other through a network, and the network includes a plurality of It refers to a connection structure in which information exchange is possible between each node, such as terminals and servers of Examples of such networks include RF, 3rd Generation Partnership Project (3GPP) network, Long Term Evolution (LTE) network, 5th Generation Partnership Project (5GPP) network, World Interoperability for Microwave Access (WIMAX) network, Internet, LAN (Local Area Network), Wireless LAN (Wireless Local Area Network), WAN (Wide Area Network), PAN (Personal Area Network), Bluetooth network, NFC network, satellite broadcasting network, analog broadcasting network, DMB (Digital Multimedia) Broadcasting) network and the like, but the present invention is not limited thereto.

The first user terminal 321 may be implemented as, for example, a computer that can access a remote server or terminal through a network. Here, the computer may include, for example, navigation, a laptop equipped with a web browser, a desktop, and a laptop.

Alternatively, the first user terminal 321 may be implemented as a terminal capable of accessing a remote server or terminal through a network. For example, as a wireless communication device that guarantees portability and mobility, navigation, Personal Communication System (PCS), Global System for Mobile communications (GSM), Personal Digital Cellular (PDC), Personal Handyphone System (PHS), and Personal Handyphone System (PDA) Digital Assistant), IMT (International Mobile Telecommunication)-2000, CDMA (Code Division Multiple Access)-2000, W-CDMA (W-Code Division Multiple Access), Wibro (Wireless Broadband Internet) terminal, smartphone, smart phone It may include all kinds of handheld-based wireless communication devices such as a smartpad and a tablet PC.

The first user terminal 321 is a device that wants to encrypt the user data data_A and store it in the storage device 330, and the user data data_A may be data requiring privacy protection, such as sensitive personal information, for example. . Alternatively, the user data data_A may be verifiable credential (VC) data.

The first user terminal 321 may share user data (data_A) with other user terminals through the instance service provided by the data sharing mediation server 310, and the instance service provided by the data sharing mediation server 310 is Each user terminal may have ownership. And, each instance service has a DID document, which is registered in the blockchain system.

The process in which the first user terminal 321 encrypts and stores the user data data_A in the storage device 330 is first performed in a state in which the DID and the DID document of the first user terminal 321 are registered in the block chain system. Create a DID and DID document of the data sharing mediation server 310 .

Among the attribute values of the DID document of the data sharing mediation server 310 associated with the first user terminal 321, capabilityInvocation and capabilityDelegation exist, and the meaning of each attribute value is as follows.

capabilityInvocation: " "

capabilityDelegation: "USERApubKey#x"

The attribute value capabilityInvocation means the DID set of the person who has the authority to utilize data, and the property value capabilityDelegation means the DID set of the person who has the right to utilize the data and the set of the person authorized to register/delete users in capabilityInvocation.

Among the DID attribute values of the data sharing intermediary server 310, the capabilityDelegation item must be the DID of the data owner, that is, the first user terminal 321, and in the above example, key information related to sharing of user data (data_A) (index is x-th key) is registered in the capabilityDelegation item.

Then, the first user terminal 321 generates a child key using the key management system, and performs an operation algorithm of encrypting the user data (data_A).

The key management system includes a key management server 410 and the first to third database devices 420, 430, and 440. First, referring to FIG. 6, the key management system recovers a private key and a public key pair. The algorithm will be described.

The key management server 410 generates a 128-bit random S1 code necessary for generating the master key, and transmits it to the first user terminal 321 . Then, the key management server 410 transfers the S1 code to the first database device 420 and stores it. The first to third database devices 440 are devices included in the key backup system and are devices capable of storing information for key restoration. In addition, the first to third database devices 440 are physically separated from each other and store different data, respectively.

The first user terminal 321 generates a 256-bit random S2 code required to generate mnemonic code words, and transmits it to the second database device 430 through the key management server 410. The S2 code is stored in the second database device 430 .

In addition, the first user terminal 321 generates a 128-bit random S3 code as a value for setting a path necessary for generating a child key, and the third database device 440 through the key management server 410 ) to store the S3 code in the third database device 440 .

The first user terminal 321 generates a mnemonic code word using the S2 code, and generates a 512-bit master seed using the generated mnemonic code word and the S1 code.

The first user terminal 321 generates a master key using the master seed, and then generates an HD wallet using the master key. That is, the first user terminal 321 generates a master private key and a master public key by using the master seed.

The first user terminal 321 sets an index to extract a child key from the master key. The index used by the first user terminal 321 for extracting the child key has a numeric value of 4 bytes (0 ~ 2 ³¹ -1).

Then, the first user terminal 321 sets a path for extracting the child key, and the path means a path for deriving the child key from the master key. The path is set as follows by dividing the 128-bit (16-byte) S3 code into four 32-bit signed integers.

S3 = s1 - s2 - s3 - s4

m / companyCode / s1 / s2 / s3 / s4 / index

The first user terminal 321 extracts a child key from the HD wallet using a CKD (Child Key Derivation) function according to the set path. As a result of extraction of the child key of the first user terminal 321, a pair of a private key and a public key pair is generated.

The first user terminal 321 transmits its own S1 code, S2 code, and S3 code values to the first to third database devices 440 through the key management server 410 and stores them. Thereafter, the child key may be extracted using the S1 code, the S2 code, and the S3 code stored in the first to third database devices 440 , and a pair of a private key and a public key may be generated.

The first user terminal 321 may use an application for encrypting user data (data_A), and through the child key extraction algorithm described above with reference to FIG. 6 , the nth child key, which is key information of KeyAgreement of the DID document, is generated. do. Here, it is assumed that the nth child key includes a private key a and a public key a G.

The first user terminal 321 generates a symmetric key S_a using the nth child key (a · (a · G) = S_a). Then, the first user terminal 321 generates a random 16-byte initial vector (iv_a) required for encryption of the user data (data_A). The first user terminal 321 encrypts the user data data_A using the symmetric key S_a and the initial vector iv_a.

E_(S_a, iv_a)(data_A)= Ciphertext_a

The first user terminal 321 makes a request to store the encrypted user data (E_data_A) to the data sharing mediation server 310, and the data sharing mediation server 310 includes the first user terminal ( 321) is registered, and if the DID of the first user terminal 321 is registered, the data sharing intermediary server 310 transmits the encrypted data (E_data_A) to the storage device 330 in the following structure. Save.

header(20byte)header(20byte)		datadata
자식키 index(4byte)child key index(4byte)	initial vector(16byte)initial vector(16byte)	암호화된 민감 데이터Encrypted sensitive data
nn	iv_aiv_a	Ciphertext_aCiphertext_a

The type of the storage device 330 is not limited in the present invention, and various types of storage devices such as cloud, local storage, and IPFS may be used.

10 is a block diagram illustrating an operation of sharing user data in a system for storing and sharing user data according to an embodiment of the present invention. 11 is a diagram exemplarily illustrating a DID document of a second user terminal in a system for storing and sharing user data according to an embodiment of the present invention. 12 is a diagram exemplarily illustrating a DID document of a data sharing mediation server in a user data storage and sharing system according to an embodiment of the present invention. 13 is a diagram exemplarily illustrating a DID document of a first user terminal in a system for storing and sharing user data according to an embodiment of the present invention. 14 is a diagram exemplarily illustrating a DID document of a second user terminal in a system for storing and sharing user data according to an embodiment of the present invention.

10 to 14, the user data storage and sharing system 300 according to an embodiment of the present invention is a data sharing mediation server 310, a first user terminal 321, a second user terminal 322, and a storage device 330 .

The second user terminal 322 provides its DID and the key index (y) to be used together to the first user terminal 321 , and requests sharing of the user data data_A of the first user. The following is an example of the key index y provided by the second user terminal 322 .

key index: did:lit:thisisB#y

The first user terminal 321 registers the DID of the second user terminal 322 in the DID document of the data sharing intermediary server 310 of the block chain system after user authentication of the second user terminal 322 . At this time, it is registered in the capabilityInvocation attribute value to determine whether to use the user data data_A of the first user terminal 321 for the second user terminal 322 .

capabilityDelegation : "did:lit:USERA#x"

capabilityInvocation : "did:lit:USERB#y"

The first user terminal 321 recovers the symmetric key S_a to decrypt the encrypted user data E_data_A. To this end, the first user terminal 321 extracts the n-th child key (a, a·G). That is, the first user terminal 321 may use an application for decrypting the encrypted user data E_data_A, and through the child key extraction algorithm described above with reference to FIG. 5 , the nth key information of KeyAgreement of the DID document Create a child key.

The first user terminal 321 decrypts the encrypted user data E_data_A downloaded from the storage device 330 .

D_(S_a, iv_a)(Ciphertext_a) = data_A

The first user terminal 321 inquires the nth public key of the second user terminal 322 . The first user terminal 321 searches the did resolver for did:lit:USERB to inquire the DID document of the second user terminal 322 . The first user terminal 321 inquires the value of the nth public key among the public keys of the second user terminal 322 (b·G).

The first user terminal 321 generates a symmetric key to be shared with the second user terminal 322 . In this case, the DID documents of the first user terminal 321 and the second user terminal 322 are inquired to utilize key information of keyAgreement.

keyAgreement: "USERBpubKey#n"

keyAgreement: "USERApubKey#n"

The shared symmetric key of the first user terminal 321 and the second user terminal 322 is obtained by using the n-th private key of the first user terminal 321 and the n-th public key of the second user terminal 322 (a) · bG), create a shared symmetric key (S_ab).

The first user terminal 321 generates a 16-byte random initial vector required for encryption (iv_ab). The first user terminal 321 encrypts the user data data_A using the shared symmetric key S_ab.

E_(S_ab, iv_ab )(data_A) = Ciphertext_ab

The first user terminal 321 transmits the initial vector iv_ab and the encrypted user data E_data_A to the second user terminal 322 (Ciphertext_ab, iv_ab).

At this time, the data sharing mediation server 310 checks whether the DID of the second user terminal 322 is registered in the DID document of the data sharing mediation server 310 associated with the first user terminal 321 of the block chain system. 2 The user terminal 322 is allowed to access. Specifically, the data sharing mediation server 310 checks whether the DID of the second user terminal 322 is registered in the capabiltiyInvocation attribute value of the DID document of the data sharing mediation server 310 associated with the first user terminal 321 . do. The data sharing mediation server 310 is the second user when the DID of the second user terminal 322 is registered in the capabiltiyInvocation attribute value of the DID document of the data sharing mediation server 310 associated with the first user terminal 321. Allows access to the data sharing mediation server 310 of the terminal 322 .

And, the second user terminal 322 also generates a shared symmetric key. In this case, the DID documents of the first user terminal 321 and the second user terminal 322 are inquired to utilize key information of keyAgreement.

keyAgreement: "USERBpubKey#n"

keyAgreement: "USERApubKey#n"

The shared symmetric key of the second user terminal 322 and the first user terminal 321 is the nth private key of the second user terminal 322, the nth public key of the first user terminal 321 (b·a· G) is used to generate a shared symmetric key (S_ab).

The second user terminal 322 shares the user data data_A of the first user terminal 321 by decrypting the encrypted user data E_data_A.

D_(S_ab, iv_ab)(Ciphertext_ab) = data_A

Referring to FIG. 15 , a computing device 1000 of a node according to an embodiment of the present invention includes a processor 1100 and a memory 1200 , and the processor 1100 includes one or more cores and a graphic processing unit and/or Alternatively, it may include a connection path (eg, a bus, etc.) for transmitting and receiving signals with other components.

The processor 1100 according to an embodiment executes one or more instructions stored in the memory 1200, thereby executing the operation of the user data storage and sharing algorithm with reference to FIGS. 5 to 14 .

For example, the processor 1100 collects information about user identification authentication and private key generation generated in one or more nodes by executing one or more instructions stored in the memory, and generates a transaction based on the collected information. Provides related information for at least one node.

Meanwhile, the processor 1100 may further include a random access memory (RAM) and a read-only memory (ROM) for temporarily and/or permanently storing signals (or data) processed therein. . In addition, the processor 1100 may be implemented in the form of a system on chip (SoC) including at least one of a graphic processing unit, a RAM, and a ROM.

The memory 1200 may store programs (one or more instructions) for processing and controlling the processor 1100 . Programs stored in the memory 1200 may be divided into a plurality of modules according to functions.

The operations of the system described in relation to the embodiments of the present invention may be implemented directly in hardware, as a software module executed by hardware, or by a combination thereof. A software module may include random access memory (RAM), read only memory (ROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory, hard disk, removable disk, CD-ROM, or It may reside in any type of computer-readable recording medium well known in the art to which the present invention pertains.

The components of the present invention may be implemented as a program (or application) to be executed in combination with a computer, which is hardware, and stored in a medium. Components of the present invention may be implemented as software programming or software components, and similarly, embodiments may include various algorithms implemented as data structures, processes, routines, or combinations of other programming constructs, including C, C++ , Java, assembler, etc. may be implemented in a programming or scripting language. Functional aspects may be implemented in an algorithm running on one or more processors.

It is to be understood that the above-described embodiments are illustrative in all respects and not restrictive, the scope of the present invention being indicated by the following claims rather than by the foregoing detailed description. And it should be construed that all changes and modifications derived from the meaning and scope of the claims as well as equivalent concepts are included in the scope of the present invention.

Claims

A user data storage and sharing system comprising a data sharing intermediary server, a first user terminal, and a storage device,

a data sharing mediation server that interworks with the blockchain network to inquire DID information registered in the blockchain network;

Registers or deletes DID information for setting access rights to user data in the DID document of the data sharing intermediary server registered in the blockchain network, and stores encrypted user data, key index information, and initial vector information in the data A first user terminal for forwarding to a shared mediation server; and

a storage device for receiving and storing the encrypted user data, the key index information, and the initial vector information from the data sharing mediation server;

When a second user terminal different from the first user terminal requests user data of the first user terminal to the data sharing intermediary server, the first user terminal transmits the DID information of the second user terminal to the block chain network Registering in the DID document of the data sharing intermediary server registered in, and granting access to the user data of the first user terminal to the second user terminal, user data storage and sharing system.
The method of claim 1,

The DID document of the data sharing mediation server registered in the blockchain network includes a first attribute value and a second attribute value,

The first attribute value includes DID information of the data owner terminal,

The second attribute value includes the DID information of the user terminal accessible to the shared data, user data storage and sharing system.
3. The method of claim 2,

When the second user terminal requests the user data of the first user terminal to the data sharing intermediary server,

The first user terminal,

decrypts the encrypted user data downloaded from the storage device, generates a shared symmetric key and a random initial vector to be shared with the second user terminal, and encrypts the decrypted user data using the shared symmetric key, A user data storage and sharing system for transferring the generated random initial vector and the encrypted user data to a second user terminal.
4. The method of claim 3,

The data sharing mediation server,

Check whether the DID information of the second user terminal is registered in the second attribute value of the DID document of the data sharing mediation server associated with the first user terminal registered in the blockchain network, and the second attribute When the DID information of the second user terminal is registered in the value, the access of the second user terminal is allowed,

The second user terminal,

A system for storing and sharing user data, generating a shared symmetric key by inquiring DID documents of the first user terminal and the second user terminal, and decrypting the encrypted user data using the generated shared symmetric key.