Abstract: The invention relates to systems, methods, network devices, and machine-readable media for encrypting and decrypting messages in a decentralized multi-authority attribute-based encryption (MA-ABE) scheme that is provably fully-adaptively secure, specifically, secure against an attacker that may corrupt some of the authorities as well as perform key queries adaptively throughout the lifetime of the system.

Abstract: The invention relates to systems, methods, network devices, and machine-readable media for encrypting and decrypting messages in a decentralized multi-authority attribute-based encryption (MA-ABE) scheme for access structures described by monotone LSSS under the decisional bilinear Diffie-Hellman assumptions. The construction can also be modified to obtain an MA-ABE scheme under computational bilinear Diffie-Hellman assumptions.

Abstract: An encryption device (20) 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 (30) 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 (40) decrypts the ciphertext by performing a pairing operation on the ciphertext generated by the encryption device (20) and the decryption key generated by the key generation device (30).

Abstract: A signature device (30) acquires a signature key SK(x?) in which an attribute vector x? is set over a basis B* of a basis B and the basis B*, which are dual bases in dual vector spaces. The signature device (30) 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 (30) outputs the signature sig and the message MSG to a verification device (40).

Abstract: The invention relates to systems, methods, network devices, and machine-readable media for encrypting and decrypting messages in a decentralized multi-authority attribute-based encryption (MA-ABE) scheme for a non-trivial class of access policies whose security is based in the random oracle model solely on the Learning With Errors (LWE) assumption. In some embodiments, any party can become an authority and there is no requirement for any global coordination other than the creation of an initial set of common reference parameters.

Abstract: A decentralized multi-authority attribute-based inner-product functional encryption FE (MA-ABIPFE) scheme in the prime-order bilinear groups under target-group-based assumptions is used for encryption. In some embodiments, any party can become an authority and there is no requirement for any global coordination other than the creation of an initial set of common reference parameters.

Abstract: A signature device (30) acquires a signature key SK(x?) in which an attribute vector x? is set over a basis B* of a basis B and the basis B*, which are dual bases in dual vector spaces. The signature device (30) 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 (30) outputs the signature sig and the message MSG to a verification device (40).

Abstract: An encryption device (20) 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 (30) 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 (40) decrypts the ciphertext by performing a pairing operation on the ciphertext generated by the encryption device (20) and the decryption key generated by the key generation device (30).