Method and server for providing notary service for file and verifying file recorded by notary service

A method for verifying a file recorded by using a notary service, comprising steps of:

• (a) a server computer acquiring a verification request for the file, in response to the server computer having acquired a notary service request for the file, and having registered a first representative value or a processed value of the first representative value in a blockchain, the first representative value being generated with a first specific value and a corresponding at least one of other values under an anchoring condition for generation of a block in the blockchain, and the first specific value being a function value of a result acquired by encoding an encoded message digest with a private key of the server computer, and the encoded message digest is generated by encoding a specific message digest of the file with a private key of a specific user;
• and
• (b) the server computer determining that verification of the file is completed in response to a determination that a second representative value or a processed value of the second representative value generated using input data included in the verification request, corresponds to the first representative value or a processed value of the first representative value,
• the step of (b) further comprising
• (b-1) the server computer performing calculating the second representative value using a second specific value allocated to a specific leaf node of a specific tree, and a value allocated to at least one of other leaf nodes,
• the step (a) further comprising
• (a-1) the server computer referring to a certain transaction ID related to the file in response to the verification request being acquired, and
• (a-2) the server computer acquiring OP message from the blockchain by referring to the certain transaction ID, and
• at the step of (b), in response to determining that the second representative value or a processed value of the second representative value generated by using the input data included in the verification request corresponds to the first representative value or a processed value of the first representative value included in the OP message, the server computer determines that the verification is completed.

A server computer for providing a notary service for a file, comprising:

• at least one memory that stores instructions;
• and
• at least one processor configured to execute the instructions to perform processes of:
• (I) responding to a notary service request being acquired from a specific user device by generating a specific message digest of the file by using a hash function, and
• (II) in response to the processor determining that an anchoring condition for generation of a block in a blockchain is satisfied, registering a representative value or a processed value of the representative value in a blockchain, (II) further comprising
• (II-1) transmitting the specific message digest to the specific user device,
• (II-2) acquiring an encoded message digest generated by encoding the specific message digest with a private key of a specific user from the specific user device,
• (II-3) generating at least one specific tree including a specific leaf node where a specific value is allocated, the specific value being a function value of a result acquired by encoding the encoded message digest with a private key of the server computer, and
• (II-4) in response to the server computer determining that the anchoring condition is satisfied, registering in the blockchain the representative value or the processed value of the representative value calculated in the specific tree by using the specific value and at least one value allocated to at least one of the other leaf nodes.

A server computer for verifying a file recorded by using a notary service, comprising:

• at least one memory that stores instructions;
• and
• at least one processor configured to execute the instructions to perform processes of:
• (I) acquiring a verification request for the file, in response to the server computer having acquired a notary service request for the file, and having registered a first representative value or a processed value of the first representative value in a blockchain, the first representative value being generated with a first specific value and a corresponding at least one of other values under an anchoring condition for generation of a block in the blockchain, and the first specific value being a function value of a result acquired by encoding an encoded message digest with a private key of the server computer, and the encoded message digest is generated by encoding a specific message digest of the file with a private key of a specific user;
• and
• (II) determining that verification of the file is completed in response to a determination that a second representative value or a processed value of the second representative value generated using input data included in the verification request, corresponds to the first representative value or a processed value of the first representative value,
• the step of (II) further comprising
• (II-1) calculating the second representative value using a second specific value allocated to a specific leaf node of a specific tree, and a value allocated to at least one of other leaf nodes,
• the step (I) further comprising
• (I-1) referring to a certain transaction ID related to the file in response to the verification request being acquired, and
• (I-2) acquiring OP message from the blockchain by referring to the certain transaction ID, and
• at the step of (II), in response to determining that the second representative value or a processed value of the second representative value generated by using the input data included in the verification request corresponds to the first representative value or a processed value of the first representative value included in the OP message, the server computer determines that the verification is completed.