Hitachi, Ltd.

Hisayoshi Satoh

Mototsugu Nishioka

Yoichi Seto

The public-key encryption method uses the sender-side apparatus by the creator of a ciphertest and creates the ciphertext of a plaintext x (&#x3b5;{0, 1}), in y=f(x0G(r)), y=H(x0G(r))r with respect to the published trapdoor-equipped unidirectional function f and the random functions G, H. Meanwhile, the receiver of the ciphertext, who has received the ciphertext by the receiver-side apparatus via the communications line, performs the decryption processing with the use of f, i.e., the secret key, in accordance with the steps inverse to those of the encryption processing.

Method of a public key encryption and a cypher communication both secure against a chosen-ciphertext attack

The public-key encryption method uses the sender-side apparatus by the creator of a ciphertest and creates the ciphertext of a plaintext x (&#x3b5;{0, 1}) in y=f (x0G(r)), y=H (x0G(r))r with respect to the published trapdoor-equipped unidirectional function f and the random functions G, H. Meanwhile, the receiver of the ciphertext, who has received the ciphertext by the receiver-side apparatus via the communications line, performs the decryption processing with the use of f, i.e., the secret key, in accordance with the steps inverse to those of the encryption processing.

Growing community of inventors

Yokohama, Japan

Hisayoshi Satoh