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AssigneeHitachi, Ltd.
InventorKen Naganuma
Estimating the term…
A client executes processing for data encryption by adding an error vector to plaintext, the error vector being not larger than a predetermined criterion and processing for sending limitation information to a server, the limitation information being formed from a sublattice basis of a lattice generated by a secret key. The server executes processing for receiving the limitation information and storing it in a storage device and in the homomorphic computation processing on the encrypted data received from the client, processing for, when a bit length of ciphertext which is a result of the homomorphic computation processing is equal to or larger than a predetermined value, reducing the bit length of the ciphertext to a value not larger than a predetermined threshold by translating a vector of the ciphertext to an inside of a region formed from the sublattice basis corresponding to the stored limitation information.
A confidential computation system which is a computer system comprising:
A confidential computation method performed in a computer system including a client configured to execute data encryption by a homomorphic encryption method using a secret key and send the encrypted data to a server, and the server configured to execute homomorphic computation processing on the encrypted data received from the client and return a result of the computation to the client, the confidential computation method characterized by comprising:
A confidential computation program executed in a computer system including a client configured to execute data encryption by a homomorphic encryption method using a secret key and send data obtained by the encryption to a server, and the server configured to execute homomorphic computation processing on the encrypted data received from the client and return a result of the computation to the client, the confidential computation program causing the client to execute
A confidential computation program executed in a computer system including a client configured to execute data encryption by a homomorphic encryption method using a secret key and send data obtained by the encryption to a server, and the server configured to execute homomorphic computation processing on the encrypted data received from the client and return a result of the computation to the client, the confidential computation program causing the server to execute
Dependencies are inferred from the claim text.