Cryptographic processing system
AssigneesMitsubishi Electric Corporation, Nippon Telegraph and Telephone Corporation
InventorsKatsuyuki Takashima, Tatsuaki Okamoto
Life of this patent
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Abstract
It is aimed to implement a hierarchical predicate encryption (HPE) scheme. A cryptographic process is performed using dual vector spaces (dual distortion vector spaces (DDVS)) of a space V and a space V* paired through a pairing operation. An encryption device generates as a cipher vector a vector in the space V, the vector having transmission information embedded therein. A decryption device, using a predetermined vector in the space V* as a key vector, performs the pairing operation on the cipher vector generated by the encryption device and the key vector, to decrypt the cipher vector and to extract information concerning the transmission information.
Claims47
A cryptographic processing system that performs a cryptographic process using dual vector spaces of a space V and a space V* paired through a pairing operation, the cryptographic processing system comprising:
- an encryption device that, using a processing device, generates as a cipher vector a vector in the space V, the vector having predetermined information embedded therein;
- and
- a decryption device that, using the processing device and using a predetermined vector in the space V* as a key vector, performs the pairing operation on the cipher vector generated by the encryption device and the key vector, to decrypt the cipher vector and to extract information concerning the predetermined information.
A key generation device that generates a key vector kL, 0 which is a secret key in a predicate encryption scheme, the key generation device comprising:
- a master key storage unit that, when a space V and a space V* are dual vector spaces paired through a pairing operation, stores in a storage device the space V* as a master secret key;
- and
- a key vector generation unit that, using a processing device, generates as the key vector kL, 0 a vector in which a predetermined value is set as a coefficient of a basis vector b*n of basis vectors b*i (i=0, . . . , N−1) in a predetermined basis B* of the space V*, and in which each of predicate information vi (i=0, . . . , μL−1) is set as a coefficient of each of basis vectors b*i (i=0, . . . , μL−1), the space V* being the master secret key stored by the master key storage unit.
A key delegation device that generates a key vector which is a secret key in a predicate encryption scheme, the key delegation device comprising:
- a key vector acquisition unit that, when a space V and a space V* are dual vector spaces paired through a pairing operation, acquires a key vector in the space V* that can decrypt predetermined cipher vectors in the space V, and
- a key vector generation unit that, using a processing device, generates a new key vector in the space V* that can decrypt some cipher vectors of the predetermined cipher vectors that can be decrypted by the key vector.
An encryption device comprising:
- a transmission information setting unit that, when a space V and a space V* are dual vector spaces paired through a pairing operation, using a processing device, generates as a transmission information vector a vector in which p is set as a coefficient of a basis vector bn of basis vectors bi (i=0, . . . , N−1) in a predetermined basis B of the space V;
- and
- a cipher vector generation unit that, using the processing device, generates a cipher vector by adding an attribute vector in which each of attribute information xi (i=0, . . . , μLx−1) is set as a coefficient of each of basis vectors bi (i=0, . . . , μLx−1) to the transmission information vector generated by the transmission information setting unit.
A decryption device comprising:
- a vector input unit that, when a space V and a space V* are dual vector spaces paired through a pairing operation, inputs as a cipher vector a vector in which ρ is set as a coefficient of a basis vector bn, of basis vectors bi (i=0, . . . , N−1) of a predetermined basis B of the space V, and in which each of attribute information xi (i=0, . . . , μLx−1) is set as a coefficient of each predetermined basis vector of basis vectors bi (i=0, . . . , μLx−1);
- a key vector storage unit that stores, as a key vector and in a storage device, a vector in which a predetermined value is set as a coefficient of a predetermined basis vector b*n of basis vectors b*i (i=0, . . . , N−1) in a predetermined basis B* of the space V*, and in which each of predicate information vi (i=0, . . . , μLv−1) is set as a coefficient of each of basis vectors b*i (i=0, . . . , μLv−1)(μLx≧vLv);
- and
- a pairing operation unit that, using a processing device, performs the paring operation on the cipher vector input by the vector input unit and the key vector stored by the key vector storage unit, and extracts from the cipher vector a value concerning the ρ set as the coefficient of the basis vector bn.
A cryptographic processing system that performs a cryptographic process using dual modules of a space V and a space V* paired through a pairing operation, the cryptographic processing system comprising:
- an encryption device that generates as a cipher vector a vector in the space V, the vector having predetermined information embedded therein;
- and
- a decryption device that, using a predetermined vector in the space V* as a key vector, performs the pairing operation on the cipher vector generated by the encryption device and the key vector, to decrypt the cipher vector and to extract information concerning the predetermined information.
A key generation device that generates a key vector kL, 0 which is a secret key in a predicate encryption scheme, the key generation device comprising:
- a master key storage unit that, when a space V and a space V* are dual modules paired through a pairing operation, stores in a storage device the space V* as a master secret key;
- and
- a key vector generation unit that generates as a key vector kL, 0 a vector in which a predetermined value is set as a coefficient of a predetermined basis b*n of basis vectors b*i (i=0, . . . , N−1) of a predetermined basis B* of the space V*, and in which each of predicate information vi (i=0, . . . , μL−1) is set as a coefficient of each of basis vectors b*i (i=0, . . . , μL−1), the space V* being the master secret key stored by the master key storage unit.
A key delegation device that generates a key vector which is a secret key in a predicate encryption scheme, the key delegation device comprising:
- a key vector acquisition unit that, when a space V and a space V* are dual modules paired through a pairing operation, acquires a key vector in the space V* which can decrypt predetermined cipher vectors in the space V;
- and
- a key vector generation unit that, using a processing device and based on the key vector acquired by the key vector acquisition unit, generates a new key vector in the space V* which can decrypt some cipher vectors of the predetermined cipher vectors that can be decrypted by the key vector.
An encryption device comprising:
- a transmission information setting unit that, when a space V and a space V* are dual modules paired through a pairing operation, generates as a transmission information vector a vector in which p is set as a coefficient of a basis vector bn of basis vectors bi (i=0, . . . , N−1) in a predetermined basis B of the space V;
- and
- a cipher vector generation unit that generates a cipher vector by adding an attribute vector in which each of attribute information xi (i=0, . . . , μLx−1) is set as a coefficient of each of basis vectors bi (i=0, . . . , μLx−1) to the transmission information vector generated by the transmission information setting unit.
A decryption device comprising:
- a vector input unit that, when a space V and a space V* are dual modules paired through a pairing operation, inputs as a cipher vector a vector in which ρ is set as a coefficient of a basis vector bn of basis vectors bi (i=0, . . . , N−1) in a predetermined basis B of the space V, and in which each of attribute information xi (i=0, . . . , μLx−1) is set as a coefficient of each predetermined basis vector of basis vectors bi (i=0, . . . , μLx−1);
- and
- a key vector storage unit that stores, as the key vector and in a storage device, a vector in which a predetermined value is set as a coefficient of a predetermined basis vector b*n of basis vectors b*i (i=0, . . . , N−1) in a predetermined basis B* of the space V*, and in which each of predicate information vi (i=0, . . . , μLv−1) is set as a coefficient of each of basis vectors b*i (i=0, . . . , μLv−1);
- and
- a pairing operation unit that performs the pairing operation on the cipher vector input by the vector input unit and the key vector stored by the key vector storage unit, and extracts from the cipher vector a value concerning the ρ set as the coefficient of the basis vector bn.
A cryptographic processing method for performing a cryptographic process using dual vector spaces of a space V and a space V* paired through a pairing operation, the cryptographic processing method comprising:
- an encryption step of, by a processing device, generating as a cipher vector a vector in the space V, the vector having predetermined information embedded therein;
- and
- a decryption step of, by the processing device, using a predetermined vector in the space V* as a key vector and performing the pairing operation on the cipher vector generated in the encryption step and the key vector, to decrypt the cipher vector and to extract information concerning the predetermined information.
A non-transitory computer-readable medium for storing computer-readable instructions there that when executed by a computer cause the computer to perform a cryptographic method using dual vector spaces of a space V and a space V* paired through a pairing operation, the method comprising:
- an encryption step of generating as a cipher vector a vector in the space V, the vector having predetermined information embedded therein;
- and
- a decryption step of using a predetermined vector in the space V* as a key vector and performing the pairing operation on the cipher vector generated by the encryption process and the key vector, to decrypt the cipher vector and to extract information concerning the predetermined information.
Dependencies are inferred from the claim text.