公开(公告)号：US11902428B2

公开(公告)日：2024-02-13

申请号：US17626443

申请日：2020-07-16

申请人： NIPPON TELEGRAPH AND TELEPHONE CORPORATION ,  National University Corporation TOYOHASHI UNIVERSITY OF TECHNOLOGY

发明人： Junichi Tomida ,  Fumitaka Hoshino ,  Akira Nagai ,  Atsushi Fujioka ,  Koutarou Suzuki

IPC分类号： H04L29/06 ,  H04L9/08 ,  H04L9/32

CPC分类号： H04L9/0825 ,  H04L9/083 ,  H04L9/0847 ,  H04L9/3242

摘要： A key exchange system in which a shared key is generated for executing encrypted communication between communication apparatuses according to an authenticated key exchange protocol using ID-based encryption, wherein each communication apparatus includes a memory and a processor configured to generate a short-term private key by using a private key of the communication apparatus; generate a short-term public key of the communication apparatus by using the short-term private key; generate private information on the communication apparatus by using the short-term private key, a short-term public key generated by another communication apparatus, and public information generated by the communication apparatus and said another communication apparatus or public information generated by a key delivering center; and generate the shared key for executing encrypted communication with said another communication apparatus by executing a pairing operation using the private key of the communication apparatus and the private information.

公开(公告)号：US11757620B2

公开(公告)日：2023-09-12

申请号：US17284907

申请日：2019-11-18

申请人： NIPPON TELEGRAPH AND TELEPHONE CORPORATION

发明人： Junichi Tomida

IPC分类号： H04L9/06 ,  H04L9/08 ,  H04L9/14 ,  H04L9/30

CPC分类号： H04L9/0618 ,  H04L2209/16

摘要： An encryption system for performing encryption and decryption by a multi-input inner product functional encryption having a function hiding property includes a setup unit configured to generate, taking a vector length m and the number of arguments μ of an inner product function as input, a master secret key msk and a public parameter pp by using a setup algorithm of a single-input inner product functional encryption having a predetermined characteristic and having a function hiding property and a key generation algorithm of a common key encryption satisfying a predetermined condition, an encryption unit configured to generate, taking the master secret key msk, the public parameter pp, an index i of the arguments, and a vector x as input, a ciphertext cti corresponding to the index i by using an encryption algorithm of the single-input inner product functional encryption and an encryption algorithm of the common key encryption.

公开(公告)号：US11909867B2

公开(公告)日：2024-02-20

申请号：US17607776

申请日：2019-05-29

申请人： NIPPON TELEGRAPH AND TELEPHONE CORPORATION

发明人： Junichi Tomida ,  Fumitaka Hoshino ,  Akira Nagai

IPC分类号： H04L9/08

CPC分类号： H04L9/0825 ,  H04L9/0827

摘要： A key exchange system, for generating a shared key for performing encrypted communication between multiple communication devices, includes the multiple communication devices. Each of the multiple communication devices includes a memory, and a processor configured to generate a short term private key by using a private key, generate a short term public key on one of asymmetric pairing groups used for the ID based encryption, by using the short term private key, and generate a shared key for performing encrypted communication with another communication device by performing a first pairing operation using a private key generated on another one of the asymmetric pairing groups and a short term public key generated in the other communication device, and performing a second pairing operation using the short term private key of the communication device and public information used in generating a private key of the other communication device.

公开(公告)号：US11533176B2

公开(公告)日：2022-12-20

申请号：US17072823

申请日：2020-10-16

申请人： Mitsubishi Electric Corporation ,  NIPPON TELEGRAPH AND TELEPHONE CORPORATION

发明人： Katsuyuki Takashima ,  Junichi Tomida

IPC分类号： H04L9/30 ,  H04L9/08 ,  H04L9/12

摘要： An inner-product functional encryption scheme in which the maximum length of a ciphertext and the maximum length of a secret key are not restricted can be constructed. An encryption device (20) generates a ciphertext ctx in which a vector x is encrypted, using encryption setting information that is of a size depending on the size of the vector x and is generated using as input public information of a fixed size. A key generation device (30) generates a secret key sky in which a vector y is set, using key setting information that is of a size depending on the size of the vector y and is generated using as input the public information. A decryption device (40) decrypts the ciphertext ctx with the secret key sky to calculate an inner-product value of the vector x and the vector y.