摘要:
A key generating device according to an embodiment of the present invention includes: a parameter determining unit that randomly determines a plurality of parameters that are needed when generating a secret key and a public key; a bilinear group selecting unit that selects a plurality of bilinear groups and bilinear mapping on the basis of the plurality of parameters; and a key generating unit that generates the secret key and the public key on the basis of the parameters and the plurality of bilinear groups.
摘要:
A key generation device according to the present invention hierarchically constructs a Y-ary tree structure where n reception devices are assigned to leaves, and forms subgroups where individual intermediate nodes existing between the leaves and a root of the Y-ary tree structure are defined as parent nodes. By providing new parameters to the individual intermediate parameters, the subgroups can be formed flexibly. In a case where no excluded customer exists or the number of excluded customers is small, the size of a header to be delivered and the calculation amount of an operation that a customer needs to perform can be reduced.
摘要:
A terminal device improved with a digraph generation method in a key distribution method of various types of broadcast encryption systems is provided. The terminal device includes an acquiring unit for acquiring information related to a set, which is selected from a plurality of sets representing a combination of a plurality of terminal devices, and which represents some or all of the plurality of terminal devices; an extracting unit for extracting the set contained in the information and to which it belongs; and a digraph generation unit for generating a directional branch for generating a key corresponding to the extracted set in a predetermined digraph formed by a plurality of directional branches.
摘要:
A key providing apparatus for providing a key used for encryption or decryption of data to a predetermined terminal device is provided. The key providing apparatus includes an acquiring unit for acquiring a digraph formed by arranging at least one directional branch connecting the coordinate points on a coordinate axis having a plurality of coordinate points each corresponded with a subset representing a combination of a plurality of terminal devices, an extracting unit for extracting information of all the directional branches contained in the directional path connecting a starting point of the digraph and a predetermined coordinate point, and a key generation unit for generating a key corresponded to a subset to which a predetermined terminal deice belongs based on the digraph, where the information of the directional branch is provided to the predetermined terminal device.
摘要:
A key generation device according to the present invention hierarchically constructs a Y-ary tree structure where n reception devices are assigned to leaves, and forms subgroups where individual intermediate nodes existing between the leaves and a root of the Y-ary tree structure are defined as parent nodes. By providing new parameters to the individual intermediate parameters, the subgroups can be formed flexibly. In a case where no excluded customer exists or the number of excluded customers is small, the size of a header to be delivered and the calculation amount of an operation that a customer needs to perform can be reduced.
摘要:
A key generating device according to an embodiment of the present invention includes: a parameter determining unit that randomly determines a plurality of parameters that are needed when generating a secret key and a public key; a bilinear group selecting unit that selects a plurality of bilinear groups and bilinear mapping on the basis of the plurality of parameters; and a key generating unit that generates the secret key and the public key on the basis of the parameters and the plurality of bilinear groups.
摘要:
There is provided an information processing apparatus according to the invention including a bilinear map selection unit for selecting a bilinear map used for a predetermined operation, a group selection unit for selecting at least two types of groups G1 and G2 used in performing the operation, a determination parameter calculation unit for calculating a determination parameter including at least either one of a computation amount required for the predetermined operation and an information amount for the predetermined operation based on each of the selected at least two types of the groups, and a group decision unit for deciding a group used in performing the operation based on the determination parameter. The group decision unit exchanges contents of the groups G1 and G2 when the computation or information amount for the group G2 is more than that for the group G1.
摘要:
There is provided an information processing unit enabling reduction of the number of keys to be held by a terminal unit and the amount of calculations necessary for decryption of encrypted data. The information processing unit configures an entire binary tree made up of n-number of leaf nodes, a root node and a plurality of intermediate nodes different from the root node and the leaf nodes and divides the entire tree into a plurality of base subtrees including n1/y number of leaf nodes to form a y-level (y is a divisor of log(n)) hierarchical structure, such that root nodes of the base subtrees at a lower level coincide with leaf nodes of the base subtree at an upper level. Further, it assigns subsets of the terminal units to nodes of the respective base subtrees and generates directed graphs where directed edges connecting coordinate points on a coordinate axis are set.
摘要:
A terminal device improved with a digraph generation method in a key distribution method of various types of broadcast encryption systems is provided. The terminal device includes an acquiring unit for acquiring information related to a set, which is selected from a plurality of sets representing a combination of a plurality of terminal devices, and which represents some or all of the plurality of terminal devices; an extracting unit for extracting the set contained in the information and to which it belongs; and a digraph generation unit for generating a directional branch for generating a key corresponding to the extracted set in a predetermined digraph formed by a plurality of directional branches.
摘要:
It relates to an information processing unit, a terminal unit, an information processing method, a key generation method and a program that enable reduction of the number of keys to be held by users and aims at providing an information processing unit capable of generating a directed-graph representing an encryption key generation logic to derive a set-key for encrypting a content or a content-key. The technique relates to a scheme that divides a set of user terminals into some subsets, allocates a set-key and an intermediate-key to each subset, and upon input of an intermediate-key correlated with a subset, outputs the set-key corresponding to the subset and the intermediate-key of the subset associated by the directed-edge. Further, it relates to a technique of replacing the directed-edge in the directed-graph with a shorter directed-edge. The effect of reducing the number of intermediate-keys held by each user is expected from the technique.