PUBLIC KEY ENCRYPTION METHOD CAPABLE OF COMPUTING RING HOMOMORPHISM, PUBLIC KEY ENCRYPTION SYSTEM CAPABLE OF COMPUTING RING HOMOMORPHISM, TRANSMISSION DEVICE, PROCESSING DEVICE, RECEPTION DEVICE, AND PROGRAM AND RECORDING MEDIUM THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a public key encryption method, capable of computing ring homomorphism, that computes a new ciphertext corresponding to addition of a plaintext and a new ciphertext corresponding to multiplication of a plaintext through computation on the ciphertexts, and has efficiency of practical use.;SOLUTION: Public key encryption having homomorphism with respect to addition is used, and a transmission device, a processing device and a reception device perform encryption processing and decryption processing. The reception device generates a secret key and a public key prior to the processing, and makes the public key open to the public. The transmission device encrypts two messages respectively and transmits them to the processing device. The processing device performs computation on the two encrypted messages having been received through a combination of the four rules of arithmetic while communicating with the reception device. The reception device decrypts the received ciphertexts into messages multiplied by the two messages.;COPYRIGHT: (C)2012,JPO&INPIT