Homomorphic encryption processing device, system including the same and method of performing homomorphic encryption processing

A method of performing homomorphic encryption processing, the method comprising:

• receiving field information representing a technology field to which homomorphic encryption processing is applied;
• generating ciphertext operation level information representing a maximum number of multiplication operations between homomorphic ciphertexts without a bootstrapping process;
• selecting a homomorphic encryption parameter based on the ciphertext operation level information;
• and
• performing one of a homomorphic encryption, a homomorphic decryption and a homomorphic operation, based on the homomorphic encryption parameter.

A homomorphic encryption system comprising:

• a homomorphic encryption processing server;
• and
• one or more homomorphic encryption clients configured to request a service to the homomorphic encryption server,
• wherein at least one of the homomorphic encryption processing server and the homomorphic encryption clients includes processing circuitry configured to
• generate ciphertext operation level information based on field information, the field information representing a technology field to which homomorphic encryption processing is applied, the ciphertext operation level information representing a maximum number of multiplication operations between homomorphic ciphertexts without a bootstrapping process;
• select and output a homomorphic encryption parameter based on the ciphertext operation level information;
• and
• perform one of a homomorphic encryption, a homomorphic decryption and a homomorphic operation, based on the homomorphic encryption parameter.