CRYPTO LAB INC.

An electronic apparatus processing homomorphic encryption includes at least one processor including processing circuitry and memory, and the at least one processor is configured to obtain a first ciphertext by performing homomorphic encryption on plaintext data with a first secret key, obtain, through a first key switching module, a second ciphertext corresponding to a second secret key based on the first ciphertext, transmit the second ciphertext to the second key switching module, obtain, through a second key switching module, a third ciphertext corresponding to a third secret key based on the second ciphertext, transmit the third ciphertext to a decryption module, and obtain, through the decryption module, the plaintext data by decrypting the third ciphertext based on the third secret key.

Disclosed is an electronic device. The electronic device includes a communicator, a memory configured to store data for generating a key, and a processor. The processor may generate a secret key by randomly combining values within a preset range based on the data stored in the memory, generate a public key using the secret key and an error, and store the secret key and the public key in the memory, transmit the public key to an external device using the communicator, and a sum of the number of remaining values other than zero (0), among the values within the preset range, may correspond to a Hamming weight. Accordingly, encryption and decryption may be performed efficiently.

Disclosed is an electronic device which distributes secret keys by using a t-out-of-N secret sharing scheme. The electronic device includes: a communication device; a memory storing the secret key; and a processor configured to generate a plurality of secret shares corresponding to a level of 1 by segmenting the secret key corresponding to a level of zero based on a predetermined secret sharing scheme, generate a plurality of secret shares corresponding to a level of L by repeatedly performing a process of generating a plurality of secret shares corresponding to a next level by segmenting the plurality of secret shares each corresponding to the respective levels ranging from the level of 1 based on the predetermined secret sharing scheme, and transmit the plurality of secret shares corresponding to the level of L to N electronic devices through the communication device.

Disclosed is an electronic device. The electronic device includes a communicator, a memory configured to store data for generating a key, and a processor. The processor may generate a secret key by randomly combining values within a preset range based on the data stored in the memory, generate a public key using the secret key and an error, and store the secret key and the public key in the memory, transmit the public key to an external device using the communicator, and a sum of the number of remaining values other than zero (0), among the values within the preset range, may correspond to a Hamming weight. Accordingly, encryption and decryption may be performed efficiently.

Disclosed are a calculation device for encryption using a public key and an encryption method thereof. The present method comprises: a step for setting a secret key, and generating a public key using the secret key and an error extracted from a discrete Gaussian distribution or a distribution that is within a short statistical distance thereto; and a step for applying the public key to a message, and then performing a rounding process to encrypt the message. Accordingly, encryption efficiency can be enhanced.

Disclosed is a method of generating digital signature information comprising: receiving a message; computing a particular solution in which a result of calculating the particular solution in a public key becomes a function-processed output value predetermined in the received message; and generating digital signature information for the message using the computed particular solution, wherein the public key is computed using a ring having a dimension (d) represented by a power of 2 and an integer multiplication of 3 or more.

An encryption method includes: calculating a second random matrix using a first random matrix and a secret key, and generating a ciphertext corresponding to a message using the second random matrix. The generating of the ciphertext includes: performing a rounding process for sending the generated ciphertext to a smaller modulus area. The generating of the ciphertext includes performing message encryption without Gaussian sampling.

Disclosed is a method of generating digital signature information comprising: receiving a message; computing a particular solution in which a result of calculating the particular solution in a public key becomes a function-processed output value predetermined in the received message; and generating digital signature information for the message using the computed particular solution, wherein the public key is computed using a ring having a dimension (d) represented by a power of 2 and an integer multiplication of 3 or more.