Patent ID: 11909873
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Digital communication (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 6:
7. A cryptographic system comprising:
an encryption device to generate 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, wherein the basis B and a basis B* are dual bases in dual vector spaces, which are generated based on a length (n′) of a public attribute vector and a length (n) of a secret attribute vector such that each of the basis B and the basis B* consists of L partial bases, wherein L is an integer equal to n′+n, each of n′ and n is an integer greater than or equal to 1, and the public attribute vector is published;
a key generation device to generate a decryption key by setting, in the decryption key, the other one of the predicate vector and the attribute vector over the basis B*; and
a decryption device to decrypt 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.