Abstract: A tampering verification system and method for financial institution certificates are based on blockchain and verify whether one of the financial institution certificates has been tampered with by comparing the contents of the financial institution certificate at the point of first being generated by a financial institution and at the point of client issue.

Abstract: The present invention, when at least one from among chat participants requests recording of data generated by the chat participants in an environment in which a messenger bot participates in a chat, registers at least a portion of the generated data as recorded data in a database, provides a transaction ID indicating location in the database of the data registered therein to at least one participant from among the chat participants, determines, in response to a recorded data-related verification request, whether input data included in the verification request corresponds to the recorded data, and, if the input data corresponds to the recorded data, then concludes the recorded data-related verification to have been successful.

Abstract: Provided in the present invention is a method comprising steps of: (a) confirming validity of a currency issuing transaction and a currency issuer when the currency issuing transaction including (i) a specific unique nonce, (ii) a receiver of the currency, (iii) issued amount of the currency, (iv) a public key of the currency issuer, and (v) a signature value of the currency issuer signing the (i), (ii), (iii), and (iv) with a private key of the currency issuer is obtained, and if valid, registering the currency issuing transaction on a private BCDB, wherein registering includes updating a balance database by referencing amount of change in balance due to the issued amount of the currency, included in the currency issuing transaction; and (b) registering, on the public BCDB, a specific representative hash value generated by calculating an associated hash value matching the specific hash value, when a specific condition is satisfied.

Abstract: According to one aspect of the present disclosure, provided is a method for providing a notary service for a file, the method comprising the steps in which: (a) when a notary service request for a specific file is obtained, a server generates, by using a hash function, or supports the generation of, a message digest of the specific file; and (b) if a predetermined condition is satisfied, the server registers, in a database, or supports the registration of, a representative hash value or a value obtained by processing the representative hash value, the representative hash value being generated by calculating at least one neighboring hash value that matches a specific hash value, wherein the specific hash value is a hash value of the result of encrypting the message digest with a private key of a first user, a private key of a second user and a private key of the server.

Abstract: Provided is a method according to one embodiment of the present invention comprising the steps of: (a) a server generating, by means of a hash function, a message digest (MD) of a particular file when a request for authenticating same is obtained; (b) when an MD encoded with a private key of a particular user is obtained, and if (A) information for the MD, which was encoded with the private key of the particular user, decoded with a public key of the particular user matches (B) the MD generated in step (a), then the server registering, in a database, a hash value of the MD encoded with the private key of the particular user and a private key of the server; and (c) the server obtaining a transaction ID.

Abstract: A method for providing an authentication service by using a decentralized identity (DID) application of a first user device, a mobile device, is provided. The method includes steps of: (a) if a signature verification value is transmitted from a service provider server in response to a DID service requested by a second user device, a DID authentication server transmitting the signature verification value to the DID application so that the DID application transmits a user signature and a user DID to the DID authentication server, and (b) verifying the user signature by using a user public key and transmitting signature verification result information to the service provider server, or transmitting the user signature and the user DID to the service provider server, to allow the service provider server to verify the user signature by using the user public key, to thereby provide the DID service to the second user device.

Abstract: A tampering verification system and method for financial institution certificates are based on blockchain and verify whether one of the financial institution certificates has been tampered with by comparing the contents of the financial institution certificate at the point of first being generated by a financial institution and at the point of client issue.

Abstract: A method is provided for providing a notary service for a file, the method includes the steps in which: (a) when a notary service request for a specific file is obtained, server generates, by using a hash function, or supports the generation of, a message digest of the specific file; and (b) if a predetermined condition is satisfied, the server registers, in a database, or supports the registration of, a representative hash value or a value obtained by processing the representative hash value, the representative hash value being generated by calculating at least one neighboring hash value that matches a specific hash value, wherein the specific hash value is a hash value of the result of encrypting the message digest with a private key of a first user, a private key of a second user and a private key of the server.

Abstract: A method for providing a virtual asset service based on a DID (decentralized identifier) is provided. The method includes steps of: a service providing server (a) if VADs (virtual asset addresses) are registered as a whitelist and if virtual asset transmission is requested, (a1) transmitting the virtual asset from a sender's VAD to a first VAD, (a2) if the first VAD is not registered, allowing a sender's device to request for registration of receiver's KYC, transmit or register a receiver's signature to the service providing server or in a data hub, and (3) transmit a receiver's DID to the service providing server; and (b) (i) acquiring a receiver's public key and a second VAD, or acquiring the signature from the data hub (ii) verifying the signature and the first VAD, and (iii) if the first and the second VADs are identical, registering the first VAD and transmitting the virtual asset.

Abstract: A method is provided for providing a notary service for a file, the method includes the steps in which: (a) when a notary service request for a specific file is obtained, a server generates, by using a hash function, or supports the generation of, a message digest of the specific file; and (b) if a predetermined condition is satisfied, the server registers, in a database, or supports the registration of, a representative hash value or a value obtained by processing the representative hash value, the representative hash value being generated by calculating at least one neighboring hash value that matches a specific hash value, wherein the specific hash value is a hash value of the result of encrypting the message digest with a private key of a first user, a private key of a second user and a private key of the server.

Abstract: A method for providing a relational DID (decentralized identifier) service is provided. The method includes steps of: if a specific entity's device broadcasts to a blockchain network a request for registration of relational information which represents a relation between a specific entity's DID and another entity's DID and is set by another entity and confirmed by a specific entity, a blockchain node in the blockchain network (i) verifying the request and registering the relational information in the blockchain network as corresponding to the specific entity's DID and said another entity's DID or (ii) transmitting the request to an identity contract registered in the blockchain network, to allow the identity contract to verify the request and to register the relational information in the blockchain network as corresponding to the specific entity's DID and said another entity's DID.

Abstract: A method for providing a virtual asset service based on a DID (decentralized identifier) is provided. The method includes steps of: a service providing server (a) if VADs (virtual asset addresses) are registered as a whitelist and if virtual asset transmission is requested, (a1) transmitting the virtual asset from a sender's VAD to a first VAD, (a2) if the first VAD is not registered, allowing a sender's device to request for registration of receiver's KYC, transmit or register a receiver's signature to the service providing server or in a data hub, and (3) transmit a receiver's DID to the service providing server; and (b) (i) acquiring a receiver's public key and a second VAD, or acquiring the signature from the data hub (ii) verifying the signature and the first VAD, and (iii) if the first and the second VADs are identical, registering the first VAD and transmitting the virtual asset.

Abstract: The present invention relates to an accredited certificate issuance system based on a block chain and a method using the same, and an accredited certificate authentication system based on a block chain and a method using the same, which disenable a leak of a personal key by autonomously generating, storing and managing the personal key by a random number generator mounted in a terminal in which it is impossible to install a function or an additional program for physically accessing; enable a public key for accredited certification to be stored in a block chain of electronic wallets mounted in block chain retention servers via a P2P network-based distribution database, not in a server of an accredited certificate authority (CA), and thus incur almost no costs for maintenance and for operating the established accredited certificate issuance system; and can perform an accredited certification process without ActiveX.

Abstract: A method for issuing certificates based on a blockchain network is provided. The method includes steps of: an authentication-supporting server, (a) if personal information on a user is acquired, (i) instructing a user device to generate a public and a private key of the user and transmit the public key to the authentication-supporting server, (ii) storing the certificate including the public hey as corresponding to the personal information, and (iii) determining whether one of current anchoring conditions is satisfied; (b) if it is, generating a root hash value by a Merkle tree operation on leaf nodes including hash values of the certificates stored after a previous anchoring condition is satisfied; and (c) one of (c-1) storing the transaction including the root hash value in a distributed database on the blockchain network and (c-2) instructing a blockchain node to store the transaction in the distributed database, and acquiring a transaction ID.

Abstract: A method for authenticating a specific user by using certificates including a specific certificate of the specific user based on a blockchain network is provided. The method includes steps of: an authentication-supporting server, (a) on condition that a transaction is stored in a distributed database on the blockchain network from when a previous anchoring condition is satisfied to when a current anchoring condition is satisfied, wherein the transaction includes a root hash value created by a Merkle tree operation to leaf nodes having hash values of the certificates and the certificates including public keys of users, root hash identification information, and a transaction ID for locating the transaction on the distributed database are stored in the authentication-supporting server as corresponding to the specific user, if authentication of the specific user is requested, confirming validity of the specific certificate; and (b) if the specific certificate is valid, authenticating the specific user.

Abstract: A method for providing a certificate registration service based on a smart contract, wherein the smart contract is source code compilable into executable byte code, is configured to perform procedures if particular conditions are satisfied, and wherein integrity is verified by a consensus, is provided. The method includes steps of: (a) acquiring a public key (PubA) of a user device, an (IdhashA) which is hashed personal information, and a (VcertA) which includes validity conditions, acquiring the smart contract corresponding to the validity conditions and byte code; (b) registering the PubA, the IdhashA and the byte code with a private blockchain database, and acquiring locating certificate information (PrivTxidA) in the private blockchain database; (c) registering the PrivTxidA and a state of the smart contract with State Database (SDB); and (d) acquiring and registering a hash value calculated using the PubA, the IdhashA and the byte code, and its neighboring hash value.

Abstract: A method for creating and registering the authentication information is provided. The method includes steps of: (a) an intermediate server determining whether the specific user's public key is registered if (i) the specific user's public key and (ii) a hash value of the specific user's information or its processed value are acquired from the biometric authentication server which received a request for registration of authentication information; and (b) the intermediate server, if the specific user's public key is determined to be unregistered and at least one certain anchoring condition is satisfied, registering with a database a representative hash value or its processed value in a certain data structure, wherein the representative hash value is created by using (1) a specific hash value and (2) at least one hash value of at least one neighboring node which corresponds to a node of the specific hash value.

Abstract: A method for creating and registering authentication information is provided. The method includes steps of: (a) an intermediate server determining whether a specific user's public key is registered if (i) the specific user's public key and (ii) a hash value of the specific user's information or its processed value are acquired from a biometric authentication server which received a request for registration; (b) the intermediate server, if the specific user's public key is unregistered, creating and transmitting to a database a transaction whose outputs include (i) the specific user's public key and (ii) the hash value or its processed value (c) the intermediate server acquiring a transaction ID representing location information indicating where the transaction is stored in the database; and (d) the intermediate server notifying the biometric authentication server of a successful registration of (i) the specific user's public key and (ii) the hash value or its processed value.

Abstract: A method for secure transmission of user-authenticating information is provided. The method includes steps of: a service-providing server (a) determining whether a public key of the user is registered in a blockchain network, and instructing a user-authenticating information generator to generate user-authenticating information for reference, instructing an encrypting engine to encrypt the generated user-authenticating information for reference by using the public key of the user retrieved from the blockchain network, and instructing a message-sending part to transmit the encrypted user-authenticating information for reference to a mobile device of the user; and (b) in case that user-authenticating information for comparison is acquired from the user device and if the user-authenticating information for comparison is determined as identical to the user-authenticating information for reference, providing the user device with the service desired by the user.

Abstract: A method is provided for providing a notary service for a file, the method includes the steps in which: (a) when a notary service request for a specific file is obtained, server generates, by using a hash function, or supports the generation of, a message digest of the specific file; and (b) if a predetermined condition is satisfied, the server registers, in a database, or supports the registration of, a representative hash value or a value obtained by processing the representative hash value, the representative hash value being generated by calculating at least one neighboring hash value that matches a specific hash value, wherein the specific hash value is a hash value of the result of encrypting the message digest with a private key of a first user, a private key of a second user and a private key of the server.