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, user device, and service providing server are provided for information management using a specific tree based on a blockchain. Aspects of the described approach include registering in an open ledger of the blockchain private data that belongs to a set of private data that identifies a particular subject. Furthermore, pseudo-public data including prefix values that correspond to specific private data are generated, registered as sub-data corresponding to a sub-structure of a specific leaf node to which the specific private data is allocated. Also, a pseudo-public function is created based on the pseudo-public data allocated to the specific leaf node.

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: 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: Provided is a method according to the present invention comprising the steps of: (a) generating a message digest of a particular file when a request for authenticating same is obtained; (b) when a message digest encoded with a private key of a first user and a message digest encoded with a private key of a second user are obtained, and if the (i) (A) information for the message digest, which was encoded with the private key of the first user, decoded with a public key of the first user, (ii) (B) information for the message digest, which was encoded with the private key of the second user, decoded with a public key of the second user, and (C) the message digest generated in step (a) match, then registering, in a database, a hash value of the message digest encoded using the private key of the first user, private key of the second user and a private key of a server; and (c) obtaining a transaction ID reflecting location information of the registered hash value in the database.

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: 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 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: 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 information management using a specific tree based on a blockchain is provided. The method includes steps of: a user device (a) if private data related to a subject are acquired from a specific user of the user device, generating the specific tree, wherein the specific tree has leaf nodes to which private function values, created by applying its algorithm to the private data or their processed values, is allocated; and (b) (i) performing one of (i-1) registering a representative value of the specific tree as a subject ID of the subject and (i-2) registering information on the specific tree as the subject ID of the subject, in the blockchain, and (ii) supports another device to register one of (ii-1) the representative value of the specific tree as the subject ID and (ii-2) the information on the specific tree as the subject ID, in the blockchain.

Abstract: A method for providing a notary service for a file is provided. The method includes 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 specific user and a private key of the server.

Abstract: The present invention relates to a method for issuing a currency comprising the steps of: (a) confirming the validity of a currency issuing transaction and a currency issuer, when the currency issuing transaction for issuing the currency from the currency issuer is obtained, the currency issuing transaction including (i) currency receiver information, (ii) issued amount of the currency, (iii) a public key of the currency issuer, and (iv) a signature value of the currency issuer signing the (i), (ii), and (iii) with a private key of the currency issuer; and (b) registering the currency issuing transaction or a function value thereof on a public blockchain network, and obtaining a currency issuance public transaction ID indicating location information of the currency issuing transaction or the function value thereof on the public blockchain network, when the currency issuing transaction and the currency issuer are deemed valid.

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: The present invention provides a method for issuing an electronic voucher, the method comprising: (a) a step in which a server checks whether or not (i) electronic voucher data, (ii) a public key of a specific issuer and (iii) a signature value of the specific issuer are valid; and (b) a step in which, if the validity check result is positive, the server registers or supports the registration of a function value associated with (i) the electronic voucher data, (ii) the public key of the specific issuer and (iii) the signature value of the specific issuer in a public blockchain network, and acquires or supports the acquisition of Txid indicating information on the location of the function value, registered in the public blockchain network, within the public blockchain network.

Abstract: A method for providing a notary service for a file is provided. The method includes 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 specific user and a private key of the server.

Abstract: A secure information transmitting system and method for personal identity authentication, which, on the basis of a user public key, encrypt and transmit an authentication number transmitted from a server that provides a service to a user to a mobile communication terminal of the user, thereby preventing an unauthorized user who obtained the authentication number from being recognized even if an authentication number is externally exposed through hacking.

Abstract: A positive active material for a rechargeable lithium battery includes a LiCoO2 particle. An interior of the particle has a layered structure and a surface of the particle has a spinel structure.

Abstract: A method is provided for providing a notary service for a file, the method including 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 specific user and a private key of the server.

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.