Abstract: A method and an apparatus for generating a secret key for encrypted communication using a synchronized neural network, which includes: generating initial codewords based on a bit string of weight values of the synchronized neural network and transmitting a first partial codeword of the initial codewords to a device of another party; receiving a second partial codeword generated by the device of the other party and combining final codewords based on the second partial codeword received from the device of the party and the bit string of the weight values; performing an error correction on the combined final codewords and transmitting first restoration success information according to the error correction to the device of the other party; and receiving second restoration success information from the device of the other party and generating the secret key based on the restoration success information of the device of the other party, are provided.

Abstract: Disclosed are an encryption database device, method, and system. The encryption database device includes a memory configured to store and read information, and a processor configured to control the storing and reading of the memory, wherein the processor is configured to allocate blocks to the memory and store at least one ciphertext for plaintext for each of the blocks, generate mapping information associating order information of the plaintext with block information obtained by encrypting a start position of the block in which the ciphertext is stored, access the block associated with the order information corresponding to a search range of the plaintext requested by a client using the mapping information, and respond with information related to the ciphertext of the accessed block to the client.

Abstract: Disclosed herein is a method for encoding order information. The method may include generating multiple binary trees, preparing multiple different secret keys, determining a binary tree corresponding to any one secret key selected from among the multiple secret keys, and encoding the order information of the determined binary tree.

Abstract: Disclosed herein are a key generation apparatus and method based on machine learning. The key generation method includes generating, by first and second key generation apparatuses, first and second commit values, and uploading the first commit value and the second commit value to an external repository, training, by the first and second key generation apparatuses, a neural network so as to match weight values with each other, sharing, by the first and second key generation apparatuses, the first and second commit values with each other, comparing shared first and second commit values with uploaded commit values, and then verifying the commit values, and when verification of the commit values has succeeded, generating, by the first and second key generation apparatuses, hash values using the matched weight value, verifying whether the hash values are identical to each other, and generating a session secret key based on a result of verification.

Abstract: A method of providing a search index based on a Bloom filter in a distributed data sharing environment based a block chain includes generating, by a data generating device, Bloom filters used as the search index on the basis of a hash value calculated by applying a hash function to a keyword set for searching for data which is to be shared, generating, by a block providing server, a new block on the basis of the Bloom filters and the data received from the data generating device and performing proof of work (PoW) on the new block, for adding the new block to the block chain, and distributing, by a block distributing server, block chain data including the new block added to the block chain.

Abstract: A method and an apparatus for generating a secret key for encrypted communication using a synchronized neural network, which includes: generating initial codewords based on a bit string of weight values of the synchronized neural network and transmitting a first partial codeword of the initial codewords to a device of another party; receiving a second partial codeword generated by the device of the other party and combining final codewords based on the second partial codeword received from the device of the party and the bit string of the weight values; performing an error correction on the combined final codewords and transmitting first restoration success information according to the error correction to the device of the other party; and receiving second restoration success information from the device of the other party and generating the secret key based on the restoration success information of the device of the other party, are provided.

Abstract: Disclosed herein is a method of operating a data management apparatus. The method may include segmenting, by a client device, data into multiple data blocks, generating, by the client device, tags corresponding to the multiple data blocks, generating, by the client device, a representative value by accumulating the tags, generating, by the client device, a client signature value by signing the representative value and a counter value corresponding to the last updated data block, among the multiple data blocks, and transmitting, by the client device, the data and the client signature value to a server.

Abstract: In the present invention, by providing an apparatus for securing data comprising a memory for storing information for data processing, a processor configured to partition original data into a plurality of partial data and generate a plurality of divided data by randomly determining positions of each of the plurality of partial data within the original data, and a communication interface configured to transmit each of the plurality of divided data to each of a plurality of servers, respectively, if an attacker obtains a portion of the divided data, it prevents the entire original data from being restored, and the legitimate user can restore the original data accurately even if some divided data is corrupted, and provides an efficient data polymorphic dividing technique that can minimize the amount of calculation required to secure data.

Abstract: A method for secure distributed data management for dynamic data includes segmenting original data into multiple pieces, generating state information pertaining to row-based data configured with data blocks, and generating additional information for recovering the state information and the row-based data. The data blocks, corresponding to the segmented data, are stored in data servers, and each of the data servers stores data blocks selected at an interval corresponding to the number of data servers in order to store the segmented data.

Abstract: A method of providing a search index based on a Bloom filter in a distributed data sharing environment based a block chain includes generating, by a data generating device, Bloom filters used as the search index on the basis of a hash value calculated by applying a hash function to a keyword set for searching for data which is to be shared, generating, by a block providing server, a new block on the basis of the Bloom filters and the data received from the data generating device and performing proof of work (PoW) on the new block, for adding the new block to the block chain, and distributing, by a block distributing server, block chain data including the new block added to the block chain.

Abstract: The present invention relates to a method and device for verifying data ownership. The user may verify whether the server actually owns the data to be uploaded by him, and the server may simultaneously verify whether the user actually owns the data.

Abstract: Provided are a method and a system for an additive homomorphic encryption scheme with operation error detection functionality. A plaintext is obtained by decrypting a ciphertext encrypted based on a homomorphic encryption technique and subjected to an operation and lower setting bits corresponding to additional secret information included in a final private-key are extracted as plaintext information from the acquired plaintext. An operation error check is performed on the remaining bits other than the lower setting bits in the acquired plaintext.

Abstract: In the present invention, by providing an apparatus for securing data comprising a memory for storing information for data processing, a processor configured to partition original data into a plurality of partial data and generate a plurality of divided data by randomly determining positions of each of the plurality of partial data within the original data, and a communication interface configured to transmit each of the plurality of divided data to each of a plurality of servers, respectively, if an attacker obtains a portion of the divided data, it prevents the entire original data from being restored, and the legitimate user can restore the original data accurately even if some divided data is corrupted, and provides an efficient data polymorphic dividing technique that can minimize the amount of calculation required to secure data.

Abstract: In a client, an encryption key is created using plain text data, a first tag is created using the encryption key, and the plain text data are encrypted under the encryption key to create encrypted data. The first tag is transmitted to the server to confirm whether the encrypted data is duplicated and after transmitting the first tag, the encrypted data is transmitted to the server in accordance with the request of the encrypted data from the server.

Abstract: A method for storing an encrypted file by a server is provided. The server receives a first encrypted file identifier from a client. The server generates a random number and transmits the random number to the client, when the first encrypted file identifier is present in a first database. The server generates a first verification value using the random number. In addition, the server confirms whether or not the client possesses a first encrypted file corresponding to the first encrypted file identifier among encrypted files stored in a second database by comparing the first verification value and a second verification value based on the random number with each other, when receiving the second verification value from the client.

Abstract: The present invention relates to a method and device for verifying data ownership. The user may verify whether the server actually owns the data to be uploaded by him, and the server may simultaneously verify whether the user actually owns the data.

Abstract: In a client, an encryption key is created using plain text data, a first tag is created using the encryption key, and the plain text data are encrypted under the encryption key to create encrypted data. The first tag is transmitted to the server to confirm whether the encrypted data is duplicated and after transmitting the first tag, the encrypted data is transmitted to the server in accordance with the request of the encrypted data from the server.

Abstract: Provided are a method and a system for an additive homomorphic encryption scheme with operation error detection functionality. A plaintext is obtained by decrypting a ciphertext encrypted based on a homomorphic encryption technique and subjected to an operation and lower setting bits corresponding to additional secret information included in a final private-key are extracted as plaintext information from the acquired plaintext. An operation error check is performed on the remaining bits other than the lower setting bits in the acquired plaintext.

Abstract: The present invention relates to a technique which provides a function of compressed encryption large pieces of plaintext information in a single ciphertext in order to improve a space efficiency of the encryption data which occupies most of a storage space to design an efficient SHE technique which is a base of the FHE technique design. More specifically, the present invention relates to a technique which is designed to improve a structure in which only one bit is encrypted/decrypted in the technique of the prior art to encrypt/decrypt multiple bit information to improve the space efficiency for storing a ciphertext.

Abstract: The present invention relates to a compressed encryption and decryption apparatus comprising: an interface receiving a public key, a secret key and a compression ratio; a memory storing instructions for encryption and decryption of plaintexts; and a processor encrypting and decrypting plaintexts according to the instruction, wherein the instruction comprises instructions performing; generating an extended public key and an extended secret key by revising the public key and the secret key according to the compression ratio; outputting the extended public key; receiving compressed ciphertext; and decrypting the compressed ciphertext using modulo operation for multiplication of the extended secret key and the compressed ciphertext.