KR102368525B1 - System and Method for Managing Digital document using Blockchain and IPFS - Google Patents

Abstract

The present invention relates to a system for managing a digital document which uses multilateral agreement as well as a threshold value signature for managing high reliability approach in a digital document using blockchain and an InterPlanetary File System (IPS), and a driving method thereof. The system for managing a digital document comprises: a key generator to generate at least one partial scret key for storing a digital doucment according to a document storing request from a user terminal; a key issue unit to issue the generated partial scret key to at least one user; and an access allowing unit to allow access to a document when a partial scret key signature greater than a threshold value is authenticated using the issued scret key according to access request to the digital document from the user terminal. The system for managing a digital document may distribute an access authority to the digital doucment using a signal scheme greater than a threshold value of the partial scret key to prevent dogmatic and malicious action or danger due to secret key deodorization, and may be safe and reliable using a smart contract in a signature scheme.

Description

System and Method for Managing Digital document using Blockchain and IPFS

The present invention relates to a digital document management system and a method for driving the same, and more particularly, using a multi-party agreement including a threshold signature to manage reliable access to digital documents using blockchain and IPFS (InterPlanetary File System) It relates to a digital document management system and a driving method thereof.

In general, a blockchain is a peer-to-peer electronic ledger implemented as a computer-based decentralized system composed of blocks, which in turn are composed of transactions. Each transaction is a data structure that encodes the transfer of control of a digital asset between participants in a blockchain system, and includes at least one input and at least one output. With each block containing the hash of the previous block, the blocks are chained together to create a permanent, immutable record of every transaction written to the blockchain from the beginning.

Blockchain technology refers to a technology that distributes and stores data to provide data integrity. There are two main types of block chain: private block chain, consortium block chain, and public block chain. In the case of a public blockchain, anyone can participate, and in the case of a private blockchain, only authorized nodes can participate in the blockchain network.

The concept of decentralization is fundamental to the Bitcoin methodology. Decentralized systems offer the advantage of not having a single point of failure, unlike decentralized or centralized systems. Thus, the system provides an improved level of security and resiliency. This security is further improved using known encryption techniques such as elliptic curve cryptography and ECDSA.

KR 10-2018-0104767 A KR 10-2020-0041338 A

The present invention is derived from such a technical background, and in order to access a digital document, it uses a signature method exceeding the threshold value of the partial private key to distribute the access rights of the digital document, thereby risking arbitrary and malicious actions or theft of the private key. The purpose of this is to provide a more secure and reliable digital document management system and its driving method by using a smart contract for the signature method.

In addition, by using IPFS to store digital documents, it is intended to provide a digital document management system that can safely store digital documents without risk of loss and a driving method thereof.

The present invention for achieving the above object includes the following configuration.

That is, the digital document management system according to an embodiment of the present invention includes a key generator for generating at least one partial secret key for storing digital documents in response to a document storage request from a user terminal, and at least the generated partial secret key. a key issuing unit issued to one or more users, and an access permitting unit that allows access to the document when a partial private key signature over a threshold value is authenticated using the issued private key when an access request is made to a digital document stored from the user terminal; .

Meanwhile, in a digital document management method performed in a digital document management system including a key generation unit, a key issuing unit, and an access permitting unit, at least one part for the key generation unit to store a digital document in response to a document storage request from a user terminal In the steps of generating a secret key, the key issuing unit issuing the generated partial secret key to at least one user, and requesting access to the digital document stored from the user terminal, the access permitting unit uses the issued secret key and allowing document access when the partial secret key signature greater than the threshold is authenticated.

According to the present invention, in order to access a digital document, it is possible to prevent arbitrary and malicious actions or the risk of stealing the private key by distributing the access rights of the digital document by using a signature method greater than the threshold value of the partial private key. By using a smart contract, the effect of providing a more secure and reliable digital document management system and its driving method is derived.

In addition, by using IPFS to store digital documents, there is an effect of providing a digital document management system that can safely store digital documents without risk of loss and a driving method thereof.

1 is a block diagram showing the configuration of a digital document management system according to an embodiment of the present invention;
2 is an exemplary diagram for explaining the operation of a digital document management system according to an embodiment of the present invention;
3 is an exemplary diagram for explaining a process of storing a digital document in response to a digital document protection request from a user in the digital document management system according to an embodiment of the present invention;
4 is an exemplary diagram for explaining a process of inquiring a digital document according to a digital document inquiry request from a user in the digital document management system according to an embodiment of the present invention;
5 is a flowchart illustrating a digital document management method according to an embodiment of the present invention;
6 is a flowchart illustrating a digital document storage process in a digital document management method according to an embodiment of the present invention;
7 is a flowchart illustrating a digital document inquiry process in a digital document management method according to an embodiment of the present invention.

It should be noted that the technical terms used in the present invention are only used to describe specific embodiments, and are not intended to limit the present invention. In addition, the technical terms used in the present invention should be interpreted as meanings generally understood by those of ordinary skill in the art to which the present invention belongs, unless otherwise specifically defined in the present invention, and excessively comprehensive It should not be construed in the meaning of a human being or in an excessively reduced meaning.

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

1 is a block diagram illustrating a configuration of a digital document management system according to an embodiment of the present invention.

The digital document management system 10 according to an embodiment of the present invention relates to a technology using multi-party agreements including IPFS, block chain, and threshold signature for the management of highly reliable digital assets (documents), that is, digital documents. The digital document is encrypted and stored in the IPFS 30, and the hash value for accessing the encrypted stored digital document and partial secret keys for signing the threshold value are stored in the block chain to safely store the digital document. In other words, it is characterized in that a multi-party agreement is reached by signing a user above a threshold using a smart contract on the block chain 40 .

In addition, the secret key used to encrypt the digital document is divided or recombined into several pieces, the digital document encrypted through IPFS is stored, the hash value and partial secret keys are stored for access from IPFS, and the secret key retrieval function and digital document access Use a smart contract that includes a signature function for

The digital document management system 10 according to an embodiment of the present invention stores an encrypted digital document using a new secret key, and converts a hash value for accessing the encrypted digital document, but by accessing the docu contract By verifying the user's own signature through the secret key retrieval function, only the user's own partial private key can be safely retrieved.

1 , the digital document management system 10 according to an embodiment includes a communication unit 110 , a key generation unit 120 , a key issuing unit 130 , a document storage unit 140 , and an access permission unit 150 . includes

The communication unit 110 communicates with any internal component or at least one external terminal through a wired/wireless communication network. In this case, the external arbitrary terminal may include user terminal 1, user terminal 2, user terminal 3.. (20-1, 20-2, 20-3...), and the like.

Here, as wireless Internet technologies, wireless LAN (WLAN), DLNA (Digital Living Network Alliance), WiBro (Wireless Broadband: Wibro), Wimax (World Interoperability for Microwave Access: Wimax), HSDPA (High Speed Downlink Packet Access) ), High Speed Uplink Packet Access (HSUPA), IEEE 802.16, Long Term Evolution (LTE), Long Term Evolution-Advanced (LTE-A), Wireless Mobile Broadband Service (WMBS), etc. In this case, the communication unit 110 transmits and receives data according to at least one wireless Internet technology within a range including Internet technologies not listed above. In addition, short-range communication technologies include Bluetooth, Radio Frequency Identification (RFID), Infrared Data Association (IrDA), Ultra Wideband (UWB), ZigBee, and Near Field Communication (NFC). , Ultra Sound Communication (USC), Visible Light Communication (VLC), Wi-Fi (Wi-Fi), Wi-Fi Direct (Wi-Fi Direct), etc. may be included. In addition, the wired communication technology may include Power Line Communication (PLC), USB communication, Ethernet, serial communication, optical/coaxial cable, and the like.

In one embodiment, the communication unit 110 includes a Service Interface Layer for communicating with the user terminal 20 and an IPFS & blockchain Interface Layer for communicating with the block chain 40 and IPFS 30 . .

IPFS (InterPlanetary File System, 30) is a peer-to-peer distributed file system that attempts to connect all computing devices to the same file system.

The block chain 40 is the name of a digital public transaction ledger technology that connects the information to the existing ledger by creating a 'block' whenever a transaction occurs. Whenever a transaction occurs, a block, a mass of transaction information, is created, and when all participants approve the transaction specification, it is distributed/stored in each ledger, and the block is connected like a chain.

The user terminal 20 includes a smart phone, a portable terminal, a mobile terminal, a foldable terminal, a personal digital assistant (PDA), and a portable multimedia (PMP). Player) terminal, telematics terminal, navigation terminal, personal computer, notebook computer, slate PC, tablet PC, ultrabook, wearable device Device, for example, watch-type terminal (Smartwatch), glass-type terminal (Smart Glass), HMD (Head Mounted Display), etc.), Wibro (Wibro) terminal, IPTV (Internet Protocol Television) terminal, smart TV, for digital broadcasting It can be applied to various terminals such as a terminal, an audio video navigation (AVN) terminal, an audio/video (A/V) system, a flexible terminal, and a digital signage device.

An example of the user terminal 20 is a terminal capable of installing an application, 3G, 4G, 5G terminal, a smart phone (smart phone), a smart pad (smart pad), a tablet PC (Tablet PC), PCS (Personal Communication System) ), GSM (Global System for Mobile communications), PDC (Personal Digital Cellular), PHS (Personal Handyphone System), PDA (Personal Digital Assistant), IMT (International Mobile Telecommunication)-2000, CDMA (Code Division Multiple Access)-2000 , W-Code Division Multiple Access (W-CDMA), Wireless Broadband Internet (Wibro), and the like, may include all kinds of wireless communication devices that ensure portability and mobility.

The key generating unit 120 generates at least one or more partial secret keys for storing digital documents in response to a document storage request from the user terminal 20 . In order to store the digital document, the key generator 120 generates and issues the number (n) of partial secret keys requested by the user based on the multi-party consensus algorithm including the threshold signature.

In one aspect of the present invention, the key generator 120 generates at least one partial secret key by dividing the generated secret key by the number of participants using the Sharmir's Secret Sharing algorithm.

There is a method using the Secret Sharing algorithm as a method of using multilateral consensus including threshold signature. Among them, Sharmir's Secret Sharing is an algorithm published in 1979, which is the only K-1 polynomial that passes through K different points. It is an algorithm that uses the fact that For example, there is only one quadratic polynomial passing through three different points, and in this case, the constant term of the polynomial becomes a secret to be shared safely.

In response to a user request for archiving a digital document, the key generator 120 generates a partial secret key as many as the number (n) requested by the user based on the multi-party consensus algorithm including the threshold signature by the administrator providing the archiving service. create

And the key issuing unit 130 issues the generated partial secret key to at least one or more users.

In one aspect of the present invention, when a request for reissuing the partial secret key is received from the user terminal 20 , the key issuing unit 130 reissues the partial secret key through an agreement between users and an authentication process. There is an effect of reinforcing the security of the private key by reissuing the partial secret key after the agreement and authentication process of more than a threshold value among users who have been issued with the partial secret key is performed.

Afterwards, the access permitting unit 150 permits document access when a partial private key signature greater than or equal to a threshold is authenticated using the issued private key when an access request is made to the stored digital document from the user terminal 20 . That is, in order to access a digital document, users over a threshold value must sign using the partial secret key, thereby distributing the responsibility for trusted access to the digital document and preparing for the loss of the key, thereby improving security.

The document storage unit 140 encrypts the digital document in response to the document storage request from the user terminal 20 and stores it in the IPFS 30 , and returns a hash value for accessing the digital document storage requested from the IPFS 30 . receive

According to a characteristic aspect of the present invention, the document storage unit 140 stores the IPFS hash value of the corresponding digital document when a new digital document storage request is made, creates a new Docu contract, and distributes it to the public blockchain 40. characterized in that

At this time, the DoQ contract is created including the wallet addresses of participating users, the partial secret key bundle, and the threshold value required to recombining the secret key used for digital document encryption.

2 is an exemplary diagram for explaining the operation of a digital document management system according to an embodiment of the present invention.

The digital document management system 10 according to an embodiment is a management system that uses a multi-party agreement including a threshold signature for reliable access to a digital document.

In the digital document management system 10 according to an embodiment, in order to store digital documents, the administrator generates and issues partial secret keys as many as the number (n) requested by the user based on a multi-party consensus algorithm including threshold signatures. .

Conversely, when a user wants to access a digital document, it is possible to access the digital document by using a partial secret key over a threshold value. Therefore, since a specific user cannot access a digital document alone, security can be improved and key loss can be prepared.

In addition, it includes a module that generates n partial secret keys based on a multi-party consensus algorithm using a threshold value signature, and a module (Encryption Layer) that recovers the original secret key using a partial secret key greater than or equal to the threshold value, and the user It includes a module (Key Sharing Layer) that divides and reassembles the private key so that it can be issued and used.

And blockchains like Ethereum include smart contracts (System Contracts, Doc Contracts). At this time, not only Ethereum, but also various blockchain networks that provide smart contract functions can all be used.

To this end, as shown in FIG. 2, the digital document management system 10 uses a module (Encrypt/Decrypt Manager) for encrypting or decrypting a digital document including a secret key generating module (Key Generator) and a secret key used to encrypt the digital document. A module that divides or reconstructs into pieces (Distribute/Reconstruct Manager) and IPFS (30) that stores an encrypted digital document and a hash value and partial secret keys for accessing the encrypted digital document in IPFS (30) are stored and secret A smart contract (System Contract, Doc Contract) that includes a key retrieval function and a signature function for accessing digital documents, and IPFS and blockchain interface (IPFS & blockchain Interface) for accessing IPFS (30) and blockchain (40) layer) is included.

3 is an exemplary diagram for explaining a process of storing a digital document in response to a digital document protection request from a user in the digital document management system according to an embodiment of the present invention.

3, the digital document management system 10 according to an embodiment includes an encryption/decryption module, a secret key division/recombination module, an IPFS and block chain interface, a block chain system contract and Docu contracts, and IPFS.

The encryption/decryption module (Encrypt/Decrypt manager) includes a key generator 120 that generates a new secret key, and receives the digital document requested to be kept from the user and encrypts it using the generated secret key. .

And the secret key partitioning/reconstruct manager (Distribute/Reconstruct Manager) uses the Shamir secret sharing algorithm to split the secret key generated by the encryption/decryption module by the number of participants.

In an embodiment, the IPFS and block chain interface of the communication unit 110 controls and manages communication between the IPFS and the digital document management system 10 , and the block chain 40 and the digital document management system 10 . The IPFS 30 stores an encrypted digital document using the new secret key generated by the encryption/decryption module, and returns a hash value for accessing the encrypted digital document.

The system contract of the block chain 40 is a contract distributed to the block chain 40 that provides a smart contract function such as Ethereum when the digital document storage system 10 is initially driven, and corresponds to a new digital document storage request. The IPFS hash value of the digital document is stored, and a new document is created and automatically distributed to the blockchain 40 that provides smart contract functions such as Ethereum.

In the new DoQ contract, the wallet addresses of participating users, partial secret key bundles, and the threshold value required to reconstruct the secret key used to encrypt digital documents are stored. Users can access the DoQ contract and withdraw their encrypted partial secret key. The process involves verifying the user's own signature through the secret key retrieval function written in the DoQ contract, and then safely assigning their own portion to the user. Only the secret key can be retrieved.

In addition, the user terminal has the document contract address of the digital document requested by the user and the user's partial secret keys, and the encrypted digital document is stored in the IPFS 30, and the hash value for accessing the IPFS is stored in the system contract. It is possible to store

4 is an exemplary diagram for explaining a process of inquiring a digital document in response to a digital document inquiry request from a user in the digital document management system according to an embodiment of the present invention.

In the DoQ contract distributed on the block chain, a function to receive users’ digital document access permission signatures is written, and when the signature above the threshold value for recombining the secret key used for digital document encryption is completed, the DoQ contract is sent to the system contract. Threshold of digital document access Notifies completion of signature.

When the inquiry request of the digital document stored by the digital document management system 10 is received from the user terminal 20, the secret key division/recombination module is a portion from the user above a threshold value for recombination of the private key used for digital document encryption It receives the secret key and restores the original secret key using the Shamir secret sharing algorithm.

The digital document management system 10 according to an embodiment must obtain a hash value from the system contract through the IPFS and block chain interface that controls and manages communication with the IPFS 30 and the block chain 40 .

At this time, the digital document requested for inquiry is stored in the IPFS 30 in an encrypted state, and a hash value for accessing the encrypted digital document of the IPFS is stored in the system contract.

The IPFS 30 returns an encrypted digital document corresponding to the transmitted hash value. The encryption/decryption module decrypts the encrypted digital document returned from the IPFS 30 using the original secret key recombined in the secret key division/recombination module.

In addition, the user can safely inquire the digital document by using the signature as much as a predetermined threshold value when the digital document storage request is made through the user terminal 20 .

5 is a flowchart illustrating a digital document management method according to an embodiment of the present invention.

A digital document management method performed in a digital document management system including a key generation unit, a key issuing unit, and an access permitting unit includes first, at least one key generation unit for storing digital documents in response to a document storage request from a user terminal (S200). The above partial secret key is generated (S210).

In one aspect, the generating of the partial secret key is characterized in that at least one partial secret key is generated by dividing the generated secret key by the number of participants using the Shamir secret sharing algorithm.

Then, the key issuing unit issues the generated partial secret key to at least one user (S215).

Then, the document storage unit encrypts the digital document according to the document storage request from the user terminal, stores it in the IPFS, and receives a hash value for accessing the stored digital document from the IPFS (S220).

That is, IPFS stores an encrypted digital document using the new secret key generated by the encryption/decryption module, and returns a hash value for accessing the encrypted digital document.

At this time, receiving the hash value includes a series of processes of storing the IPFS hash value of the digital document corresponding to the request for storage of a new digital document, creating a new Docu contract and distributing it to the blockchain 40 such as Ethereum do.

That is, the system contract of the block chain 40 is a contract that is distributed to a block chain such as Ethereum when the digital document storage system 10 is initially operated. When a new digital document storage request is made, the IPFS hash value of the digital document Save, create a new DoQ contract, and automatically distribute it to a blockchain such as Ethereum.

The digital document management method according to an embodiment stores a threshold value necessary for recombining the wallet addresses and partial secret key bundles of users participating in the new docu contract, and the secret key used for digital document encryption (S230).

The user terminal has the document contract address of the digital document requested by the user and the user's partial secret keys, and the encrypted digital document is stored in the IPFS 30, and the hash value for accessing the IPFS is stored in the system contract. It is possible to keep

Afterwards, when an inquiry or access request for a digital document stored in the digital document management system is received from the user terminal (S240), the partial secret key signature greater than the threshold value is authenticated using the private key issued by the access permitting unit 150. In case (S250), document access is allowed.

Users can access the DoQ contract and withdraw their encrypted partial secret key. The process involves verifying the user's own signature through the secret key retrieval function written in the DoQ contract, and then safely assigning their own portion to the user. Only the secret key can be retrieved.

Based on the information stored in the Dokyu contract, which includes the wallet addresses and partial secret key bundles of users participating in the Dokyu contract, and the threshold value required to recombine the secret key used to encrypt the digital document, the secret key used to encrypt the digital document is determined. The partial secret key is received from the user above the threshold for recombination, and the original secret key is restored using the Shamir secret sharing algorithm (S252).

Then, a hash value for accessing the encrypted digital document of the IPFS stored in the system contract is obtained (S254), and the encrypted digital document corresponding to the hash value transmitted from the IPFS 30 is returned.

And the encryption/decryption module decrypts the encrypted digital document returned from the IPFS 30 using the original secret key recombined in the secret key division/recombination module (S256).

After that, when a request for reissuance of the partial secret key is received from the user terminal (S260), if permission for reissuance greater than a threshold value is obtained through agreement and authentication between users (S270), the partial secret key can be reissued (S275). However, the present invention is not limited thereto.

6 is a flowchart illustrating a digital document storage process in a digital document management method according to an embodiment of the present invention;

6 , according to the digital document storage process in the digital document management method according to an embodiment, first, the digital document management system 10 receives a digital document (Doc), threshold information (K), and the number of users ( N) receive information.

The digital document management system 10 encrypts a digital document (Doc) and generates (Distribute) partial secret keys as many as N users.

Then, the encrypted digital document (end(Doc)) is uploaded to the IPFS (30), and a hash key is returned (CID). Afterwards, the digital document management system 10 stores the IPFS hash value of the digital document corresponding to the request for storage of a new digital document as a system contract of the block chain 40, and creates a new document contract with Ethereum It is automatically distributed to the same block chain 40 .

In the new Docu contract, the wallet address (addr(N)) of the participating users, the partial secret key bundle (PartialKey(N)), and the threshold value (threshold(K)) required to recombine the secret key used to encrypt the digital document are is saved Users can access the Docu contract and withdraw their encrypted partial secret key. You can safely retrieve only your own partial private key (PartialKey) assigned to the user.

In addition, the user terminal has the document contract address of the digital document requested by the user and the user's partial secret keys, and the encrypted digital document is stored in the IPFS 30, and the hash value for accessing the IPFS is stored in the system contract. It is possible to store

7 is a flowchart illustrating a digital document inquiry process in a digital document management method according to an embodiment of the present invention.

A function to receive users' digital document access permission signatures is written (DocContract.Sign()) in the DoQ contract distributed on the block chain, and when the signature above the threshold for recombining the private key used for digital document encryption is completed, , the docu contract notifies the system contract of completion of signing the threshold of digital document access.

When the inquiry request of the digital document stored by the digital document management system 10 is received from the user terminal 20, the secret key division/recombination module is a portion from the user above a threshold value for recombination of the private key used for digital document encryption Receive the secret key and restore the original secret key using the Shamir secret sharing algorithm (Reconstruct(PartialKey[K]).

The digital document management system 10 according to an embodiment must obtain a hash value from the system contract through the IPFS and block chain interface that controls and manages communication with the IPFS 30 and the block chain 40 .

At this time, the digital document requested for inquiry is stored in the IPFS 30 in an encrypted state, and a hash value for accessing the encrypted digital document of the IPFS is stored in the system contract.

The digital document management system 10 requests confirmation of the threshold signature with the system contract of the block chain (Retrieve(DocContract addr, PartialKey[K]), and when the signature of the threshold is completed in the system contract (Validate(is Signed))) hash value is delivered (CID(hash)).

The digital document management system 10 requests download of the digital document to IPFS using the obtained hash key (Download(CID(hash))), and the IPFS 30 sends an encrypted digital document corresponding to the transmitted hash value. returns (enc(Doc)).

The encryption/decryption module of the digital document management system 10 uses the original secret key reconstructed (Reconstruct(PartialKey[K])) of the encrypted digital document returned from the IPFS 30 in the secret key division/recombination module. Decrypt(enc(Doc))).

In addition, the user can safely inquire the digital document (Doc) by using the signature as much as a predetermined threshold value when the digital document storage request is made through the user terminal 20 .

The above-described method may be implemented as an application or implemented in the form of program instructions that may be executed through various computer components and recorded in a computer-readable recording medium. The computer-readable recording medium may include program instructions, data files, data structures, etc. alone or in combination.

The program instructions recorded in the computer-readable recording medium are specially designed and configured for the present invention, and may be known and available to those skilled in the computer software field.

Examples of the computer-readable recording medium include hard disks, magnetic media such as floppy disks and magnetic tapes, optical recording media such as CD-ROMs and DVDs, and magneto-optical media such as floppy disks. media), and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like.

Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device may be configured to operate as one or more software modules for carrying out the processing according to the present invention, and vice versa.

Although the above has been described with reference to the embodiments, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the following claims. will be able

10: digital document management system 20: user terminal
30: IPFS 40: Blockchain
110: communication unit 120: key generation unit
130: key issuing unit 140: document storage unit
150: access permission unit

Claims (12)

a key generator for generating at least one or more partial secret keys for storing digital documents in response to a document storage request from a user terminal;
a key issuing unit that issues the generated partial secret key to at least one user; and
When a request for access to a digital document stored from a user terminal is requested, an access permitting unit that allows document access when the partial secret key signature over a threshold value is authenticated using the issued private key;
The key generator,
At least one partial secret key is generated by dividing the generated secret key by the number of participants using the Shamir secret sharing algorithm,
In response to a document storage request from the user terminal, the digital document is encrypted and stored in IPFS, and further comprising a document storage unit that receives a hash value for accessing the digital document requested to be stored from IPFS,
The key issuing unit,
When a partial secret key reissuance request is received from the user terminal,
Among users who have been issued with a partial secret key, it is understood that a multi-party agreement is reached by signing using a smart contract on the block chain by users over a threshold value.
The document storage unit,
When a new digital document storage request is made, the IPFS hash value of the corresponding digital document is stored, a new DoQ contract is created and distributed to the public blockchain, and the DoQ contract recombines the partial secret key bundle and the secret key used to encrypt the digital document. is prepared, including the threshold values necessary for
Convert the hash value for accessing the encrypted digital document using a smart contract that includes a secret key retrieval function and a signature function for digital document access for hash value and partial secret key retrieval for accessing IPFS, A digital document management system that accesses the docu contract and retrieves only the user's partial private key by verifying the user's own signature through the secret key retrieval function.
delete delete The method of claim 1,
The document storage unit,
A digital document management system that stores the IPFS hash value of the corresponding digital document upon request for storage of a new digital document, creates a new Docu contract, and distributes it on the blockchain.
5. The method of claim 4,
The docu contract includes a threshold value required for recombining the wallet addresses and partial secret key bundles of participating users and the secret key used for digital document encryption, a digital document management system.
delete A digital document management method performed in a digital document management system including a key generation unit, a key issuing unit and an access permitting unit, the method comprising:
generating, by a key generator, at least one partial secret key for storing a digital document according to a document storage request from a user terminal;
issuing, by a key issuing unit, the generated partial secret key to at least one user; and
When an access request is made from the user terminal to the stored digital document, the access permitting unit permits access to the document when the partial secret key signature is authenticated using the issued secret key.
The step of generating the partial secret key comprises:
At least one partial secret key is generated by dividing the generated secret key by the number of participants using the Shamir secret sharing algorithm,
The document storage unit encrypts the digital document according to the document storage request from the user terminal, stores it in IPFS, and receives a hash value for accessing the digital document requested to be stored from the IPFS; further comprising;
The issuing step is
When a request for reissuance of the partial secret key is received from the user terminal, it is determined that a multi-party agreement is reached by signing using a smart contract on the block chain among users who have been issued with the partial secret key. When this is done, the partial secret key is reissued,
The document storage unit stores the IPFS hash value of the corresponding digital document when a new digital document storage request is made, creates a new docu contract and distributes it to the public blockchain, and the docu contract stores the partial secret key bundle and the secret used for digital document encryption It is written including the number of threshold values required to recombine the key;
Convert the hash value for accessing the encrypted digital document using a smart contract that includes a secret key retrieval function and a signature function for digital document access for hash value and partial secret key retrieval for accessing IPFS, A digital document management method that accesses the DoQ contract and retrieves only the user's partial private key by verifying the user's own signature through the secret key retrieval function.
delete delete 8. The method of claim 7,
The step of returning the hash value includes:
A digital document management method that stores the IPFS hash value of the corresponding digital document when a new digital document storage request is made, creates a new docu contract, and distributes it on the blockchain.
11. The method of claim 10,
The docu contract includes a threshold value necessary for recombining the wallet addresses and partial secret key bundles of participating users and the secret key used for digital document encryption, a digital document management method.
delete

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