Mitsubishi Electric Corporation

Nippon Telegraph and Telephone Corporation

Pratish Datta

Tatsuaki Okamoto

Katsuyuki Takashima

An encryption device () generates a ciphertext by setting, in the ciphertext, one of a predicate vector of arithmetic branching programs (ABP) and an attribute vector over a basis B of the basis B and a basis B*, which are dual bases in dual vector spaces. A key generation device () generates a decryption key by setting, in the decryption key, the other one of the predicate vector and the attribute vector over the basis B*. A decryption device () decrypts the ciphertext by performing a pairing operation on the ciphertext generated by the encryption device () and the decryption key generated by the key generation device ().

Decryption device, cryptographic system, and decryption method

A signature device () acquires a signature key SK(x) in which an attribute vector xis set over a basis B* of a basis B and the basis B*, which are dual bases in dual vector spaces. The signature device () generates a signature sig for a message MSG by setting predicate information of arithmetic branching programs (ABP) for the signature key SK(x). The signature device () outputs the signature sig and the message MSG to a verification device ().

Growing community of inventors

Tokyo, Japan

Pratish Datta