Abstract: The present invention provides a method of generating a sequence of pseudo-random numbers which are difficult to predict. The method includes: (i) generating a plurality of candidate pseudo-random numbers by a respectively corresponding plurality of (differently structured) linear feedback shift registers; (ii) generating a “selector number” from one or more additional linear feedback shift registers; and (iii) selecting a candidate number from the plurality of candidate numbers, based on the “selection number” to produce a selected pseudo-random number for output.

Abstract: A programmable apparatus for executing a function is disclosed. The programmable apparatus includes a physical interface configured to be connected with an external apparatus. The programmable apparatus also includes a function logic circuit configured to execute the function on the programmable apparatus. The programmable apparatus further includes a plurality of peripheral logic circuits, each of which is configured to connect the function logic circuit with the physical interface using a respective protocol. The programmable apparatus also includes a selector circuit configured to select one from among the plurality of the peripheral logic circuits to activate.

Abstract: A decryption condition addition device (300) acquires an original ciphertext cts in which a secret distribution matrix M is set as information specifying a decryption condition and acquires an additional access structure S+ which is a restriction condition to restrict the decryption condition of the original ciphertext cts. The decryption condition addition device (300) adds a row and a column which are indicated in the additional access structure S+ to the secret distribution matrix M set in the original ciphertext cts, and thereby generates an updated ciphertext cts, for which the decryption condition of the original ciphertext cts is restricted.

Abstract: The present invention provides a method of generating a sequence of pseudo-random numbers which are difficult to predict. The method includes: (i) generating a plurality of candidate pseudo-random numbers by a respectively corresponding plurality of (differently structured) linear feedback shift registers; (ii) generating a “selector number” from one or more additional linear feedback shift registers; and (iii) selecting a candidate number from the plurality of candidate numbers, based on the “selection number” to produce a selected pseudo-random number for output.

Abstract: An encryption device 200 outputs a ciphertext ct including a ciphertext c and a ciphertext c˜. The ciphertext c has been set with one of attribute information x and attribute information v related to each other. The ciphertext c˜ has been set with one of attribute information y and attribute information z related to each other. A decryption device 300 outputs a re-encryption key rk including a decryption key k*rk, a decryption key k˜*rk, and encrypted conversion information ?rk. The decryption key k*rk is obtained by converting the decryption key k* which is set with the other one of attribute information x and attribute information v, with conversion information W1,t. The decryption key k˜*rk has been set with the other one of the attribute information y and the attribute information z. The encrypted conversion information ?rk is obtained by encrypting the conversion information W1,t by setting one of attribute information x? and attribute information v? related to each other.

Abstract: The present invention provides a method of generating a sequence of pseudo-random numbers which are difficult to predict. The method includes: (i) generating a plurality of candidate pseudo-random numbers by a respectively corresponding plurality of (differently structured) linear feedback shift registers; (ii) generating a “selector number” from one or more additional linear feedback shift registers; and (iii) selecting a candidate number from the plurality of candidate numbers, based on the “selection number” to produce a selected pseudo-random number for output.

Abstract: The present invention provides a method of generating a sequence of pseudo-random numbers which are difficult to predict. The method includes: (i) generating a plurality of candidate pseudo-random numbers by a respectively corresponding plurality of (differently structured) linear feedback shift registers; (ii) generating a “selector number” from one or more additional linear feedback shift registers; and (iii) selecting a candidate number from the plurality of candidate numbers, based on the “selection number” to produce a selected pseudo-random number for output.

Abstract: An encrypted data receiving unit (201) receives encrypted data which has been encrypted, in which a decryption condition to define a user attribute of a decryption-permission user who is permitted to decrypt the encrypted data is embedded. A data storage unit (202) stores the encrypted data received by the encrypted data receiving unit (201) in an encrypted state. A revocation processing unit (209) adds revocation information in which a user attribute of a revoked user who is no longer the decryption-permission user is indicated, to an embedded decryption condition that is embedded in the encrypted data, while the encrypted data remains in an encrypted state.

Abstract: A data storage unit (202) stores encrypted data while remaining in an encrypted state, and stores decryption conditions to define a user attribute of a decryption-permission user who is permitted to decrypt the encrypted data. In a case wherein revocation information to indicate a user attribute of a revoked user who is no longer the decryption-permission user has been added to the decryption condition when update timing arrives, a revocation information removing unit (206) removes the revocation information from the decryption condition while the encrypted data remains in the encrypted state.

Abstract: A master key update apparatus (400) acquires a master public key mpk including a basis B and a master secret key msk including a basis B* which is different from the basis B included in the master public key mpk. The master key update apparatus (400) updates the basis B included in the master public key mpk with updating information upk so as to generate a new master public key mpk?, and updates the basis B* included in the master secret key msk with the updating information upk so as to generate a new master secret key msk?.

Abstract: A decryption condition addition device (300) acquires an original ciphertext cts in which a secret distribution matrix M is set as information specifying a decryption condition and acquires an additional access structure S+ which is a restriction condition to restrict the decryption condition of the original ciphertext cts. The decryption condition addition device (300) adds a row and a column which are indicated in the additional access structure S+ to the secret distribution matrix M set in the original ciphertext cts, and thereby generates an updated ciphertext cts, for which the decryption condition of the original ciphertext cts is restricted.

Abstract: In a server apparatus (301), a data storage part (303) stores a plurality of pieces of encrypted data. An index storage part (304) stores, as an index I, a data structure which is for performing search with using a function H that outputs a unique numeric value in response to an inputted keyword, the data structure having a plurality of storage areas corresponding, in one-to-one relation, to numeric values outputted from the function H, and storing, for a plurality of keywords corresponding to plaintext data, an identifier of encrypted data being post-encryption data of the plaintext data to which each keyword corresponds, in a storage area corresponding to the numeric value outputted from the function H when each keyword is inputted.

Abstract: It is an object to provide predicate encryption that can conceal both attribute information being set in a ciphertext and predicate information being set in a decryption key even in a public key setting. An encryption device 200 generates a ciphertext ctx in which attribute information x is set as a basis vector of a basis D. A conversion device 300 converts with conversion information W the basis D of the ciphertext ctx generated by the encryption device 200 to a basis B so as to generate a ciphertext CTx. A decryption device 400 decrypts the ciphertext CTx generated by the conversion device 300 with a token tkv in which predicate information v is set as a coefficient of a basis vector of a basis B* corresponding to the basis B.

Abstract: A matrix generation apparatus includes a tree structure generation part, a root processing part, and a node processing part. The tree structure generation part generates a binary tree T which expresses a logical formula F. The root processing part generates a matrix corresponding to the type of the element expressed by the root of the binary tree T, among the elements of the logical formula F. The node processing part sequentially selects nodes, other than the root, of the binary tree T, performs an operation corresponding to the type of the element expressed by each node having a child node, on the matrix M, and associates a variable being the element expressed by each node not having a child node, with one row of the matrix. The node processing part, after having selected the nodes of the binary tree T, outputs the matrix M and a mapping ?. The mapping ? is information indicating variables associated with the respective rows of the matrix M.

Abstract: An encryption device (200) outputs a ciphertext ct0 in which is set one of attribute information x0 and attribute information v0 corresponding to each other. A decryption device (300) receives a decryption key k* in which is set the other one of the attribute information x0 and the attribute information v0, and outputs a re-encryption key rk1 that includes a decryption key k*rk0 obtained by converting the received decryption key k* with conversion information r1, and includes a ciphertext ct?1 obtained by encrypting the conversion information r1 with one of attribute information x1 and attribute information v1 corresponding to each other being set. A re-encryption device (400) outputs a re-encrypted ciphertext ct1 that includes a session key K?0 obtained by decrypting the ciphertext ct0 with the decryption key k*rk0, and includes the ciphertext ct?1.

Abstract: A cryptographic system (10) uses a cryptographic scheme capable of decrypting ciphertext on which one of two pieces of information corresponding to each other is set, with a decryption key on which the other piece of information is set. A key generation apparatus (401) generates a user private key on which one of key information u and key information y corresponding to each other is set, and a re-encryption key to convert ciphertext which can be decrypted with an attribute private key on which one of user attribute information x and user attribute information v corresponding to each other is set, into a re-ciphertext on which the other of the key information u and the key information y is set. A ciphertext storage apparatus (201) stores ciphertext on which the other of the user attribute information x and the user attribute information v is set. A re-encryption apparatus (301) re-encrypts the ciphertext stored in the ciphertext storage apparatus with the re-encryption key to generate the re-ciphertext.

Abstract: An encryption device 200 outputs a ciphertext ct including a ciphertext c and a ciphertext c˜. The ciphertext c has been set with one of attribute information x and attribute information v related to each other. The ciphertext c˜ has been set with one of attribute information y and attribute information z related to each other. A decryption device 300 outputs a re-encryption key rk including a decryption key k*rk, a decryption key k˜*rk, and encrypted conversion information ?rk. The decryption key k*rk is obtained by converting the decryption key k* which is set with the other one of attribute information x and attribute information v, with conversion information W1,t. The decryption key k˜*rk has been set with the other one of the attribute information y and the attribute information z. The encrypted conversion information ?rk is obtained by encrypting the conversion information W1,t by setting one of attribute information x? and attribute information v? related to each other.

Abstract: It is an object to implement a functional proxy re-encryption scheme. A decryption device 300 transmits to a re-encryption device 400 a decryption key k*rk which is generated by converting, using conversion information W1, a decryption key k* in which is set one of attribute information x and attribute information v corresponding to each other, and encrypted conversion information ?rk which is generated by encrypting the conversion information W1 with one of attribute information x? and attribute information v? corresponding to each other being set.

Abstract: It is an object to provide predicate encryption that can conceal both attribute information being set in a ciphertext and predicate information being set in a decryption key even in a public key setting. An encryption device 200 generates a ciphertext ctx in which attribute information x is set as a basis vector of a basis D. A conversion device 300 converts with conversion information W the basis D of the ciphertext ctx generated by the encryption device 200 to a basis B so as to generate a ciphertext CTx. A decryption device 400 decrypts the ciphertext CTx generated by the conversion device 300 with a token tkv in which predicate information v is set as a coefficient of a basis vector of a basis B* corresponding to the basis B.

Abstract: It is an object to implement a functional proxy re-encryption scheme. A decryption device 300 transmits to a re-encryption device 400 a decryption key k*rk which is generated by converting, using conversion information W1, a decryption key k* in which is set one of attribute information x and attribute information v corresponding to each other, and encrypted conversion information ?rk which is generated by encrypting the conversion information W1 with one of attribute information x? and attribute information v? corresponding to each other being set.