77 results about "Proxy re-encryption" patented technology

The invention discloses a blockchain-based data cloud storage encryption method and system. The method includes the following steps that: a data owner uses a symmetric key to encrypt a file so as to obtain a file ciphertext, and then, encrypts the symmetric key by using the public key of the data owner so as to obtain a key ciphertext, and the data owner uses the public key of an attribute key pair to perform secondary encryption on the key ciphertext, and stores the file ciphertext and the key ciphertext which has been subjected to secondary encryption to could, wherein the attribute encryption public and private key pair is generated by a proxy re-encryption module; the proxy re-encryption module generates a re-encryption key that authorizes access to the file ciphertext to a data visitor, and writes the re-encryption key and the private key of the attribute encryption public and private key pair into a blockchain; and the data owner writs the access control policy of the file ciphertext into a smart contract. According to the blockchain-based data cloud storage encryption method and system of the embodiments of the invention, the re-encryption technology and the attribute encryption technology are combined, so that the encrypted storage of data files on the cloud can be realized; and the smart contract technology is used to realize the access control of the data on the cloud, and therefore, the privacy and security of the data can be fully guaranteed.

The invention is applicable to the field of data storage technology improvement, and provides a file security sharing method based on blockchain cloud storage. The method includes the steps as follows: S1, performing data encryption on a file by using a symmetric encryption algorithm, and storing a data ciphertext in a cloud disk; S2, enabling a user to generate a key ciphertext by using a symmetric key for decrypting the data ciphertext through encryption, and storing the storage locations of the key ciphertext and the data ciphertext together on a blockchain as a part of metadata; and S3, performing proxy re-encryption on the stored file data by using a new key, and securely sharing the data through the new key and the re-encrypted new ciphertext. Through the implementation of a cloud security storage and sharing mechanism for a private file under a decentralized storage architecture of the blockchain, the data stored in the cloud by the user can only be accessed through a private key, when the own encrypted data needs to be shared to other users, the own original key of an owner cannot be exposed to other people, and the process of downloading all cloud data, re-encrypting the data by using a shared key, and then uploading the data in sequence is not required.

The invention provides a method and device with a privacy protection function for data sharing and publishing. A data owner encrypts own data and data-related keywords according to a preset demand and then stores the data and the data-related keywords at a service provider, a user sends a keyword query request to the service provider, the service provider forwards the received keyword query request to the data owner, the data owner authorizes the service provider by issuing a proxy re-encryption key to the service provider, the service provider, by utilizing the query request of the user, verifies available encrypted files satisfying the query request by comparing the trap door information of a pre-stored encryption query keyword with the trap door information of a hidden query keyword, then the service provider uses the proxy re-encryption key for encrypting the encrypted files satisfying the query request of the user and provides the encrypted files for the user, and the user decrypts the files with own private key, thus data privacy of the data owner is put under protection and the data of the data owner is shared with the authorized legal user.

The invention discloses a method for realizing timely user attribute cancel based on ciphertext-policy attribute-based encryption. The method is realized by the following steps: a system is established to generate a system public key and a master key; an encipherer constructs an access strategy; the encipherer carries out encryption to generate a ciphertext; an attribute authority center generates a user private key and an authorization private key; a cloud server constructs a path secret key binary tree; the cloud server carries out proxy re-encryption and generates a re-ciphertext to realize the cancel of user attributes; and a decipher carries out decryption to obtain a plaintext. The method helps to reduce the burden of the attribute authority center, and can solve the private key updating problem corresponding to the attribute cancel quickly and efficiently; when one or some attributes of a user is cancelled, access authority for other attributes is still reserved; and the cancelling of one or some attributes of the user does not influence the access authorities of other uses to the cancelled attribute; and the method has the advantages of being capable of cancelling the user attributes in a flexible, timely, fine-grained and efficient manner.

A block chain ciphertext cloud storage sharing method based on attribute proxy re-encryption is provided. On the basis of proxy re-encryption and attribute-based encryption technology, the invention proposes a block chain ciphertext storage sharing idea based on attribute proxy re-encryption for keyword retrieval. The metadata ciphertext is stored separately from the original information ciphertext by the attribute proxy re-encryption algorithm, the pool verification pool mechanism of block chain technology is used to determine the bookkeeping weight of the node, the information interaction contract is introduced to audit the identity of the user, and the transaction cost is automatically cleared. The security and the experimental analysis show that the invention shortens the encryption and decryption time, and reduces the high-frequency access pressure of the cloud memory. When the number of attributes is 100, the time consuming of re-encryption and decryption is 1.69 s, and the efficiency of the system is improved by 19.04%-49.68%. The method has stronger anti-collusion aggression, and has good application prospect in the field of internet of things.

The invention discloses a CP-ABE-based fixed ciphertext length proxy re-encryption system and method in cloud computing. By the adoption of the method, efficient safe access and sharing of a data file in the cloud computing environment are achieved. According to the method, on one hand, the proxy re-encryption technology is adopted for ciphertext conversion so that a ciphertext which can be decrypted by an authorizer can be converted into a ciphertext which can be decrypted by an authorized person, to be specific, after a file of a data owner is encrypted and uploaded to a cloud proxy server, under the condition that the authorizer is not available, the cloud proxy server re-encrypts the encrypted file, and the authorized person can acquire a plaintext through decryption with a private key of the authorized person after acquiring the re-encrypted file from the cloud proxy server, so that safe access and sharing of data are guaranteed; on the other hand, during ciphertext encryption, the CP-ABE-based fixed ciphertext length algorithm is adopted for ciphertext computing, so that the length of the ciphertext is fixed and does not increase along with the increase of the number of attributes, and then computing expenses are effectively reduced.

The invention provides an authorized file sharing method and a device. The method comprises the following steps: generating a re-encryption key according to the file sharing request and the private key of the file owner, wherein the file sharing request includes a file requester public key and file identification information; sending the re-encryption key and the file identification information tothe smart contract on the block chain, so that the intelligent contract uses the file identification information to query the correspondence between the pre-established file identification information and the cipher text of the file information encrypted by the file owner's public key, obtaining the ciphertext of the file information encrypted by the public key of the file owner, and performing proxy re-encryption on the ciphertext of the file information by using the re-encryption key; the re-encrypted ciphertext being decrypted using the private key of the file requester. The plaintext of the decrypted file information is used for obtaining the file corresponding to the file identification information. The invention can protect data security and ensure data ownership by using block chain and proxy re-encryption.

In an embodiment, content may be encrypted by a first device using a dual hash chain technique, where the first device maintains a forward hash chain and a second device maintains a backward hash chain, and content keys for encrypting content are derived using values of the forward and backward hash chains. The second device may not have knowledge of a seed used to generate the forward hash chain, and therefore may be unable to generate the content keys, reducing a likelihood that the encrypted content becomes compromised. Additionally, embodiments provide for techniques for using proxy re-encryption (PRE) to re-encrypt content, such that the encrypted content may be provided to and decrypted by a requesting device without knowledge of the forward and backward hash chains. Additionally, embodiments provide techniques for distributing encrypted content to a requesting device with fine-grained access control.

The systems and methods on a blockchain platform for one or more intermediaries for services including proxy re-encryption, independent audit, multiple-signatures based smart wallet associated with a smart contract and split-key authentication to achieve secure passwordless login. Proxy re-encryption by receiving a ciphertext from a first user with condition parameters that has been encrypted with a dynamically selected encryption algorithm. Audit service receiving an encrypted file from a user for storage on the blockchain platform; enforcing the security policy parameters for all access requests to the file on the blockchain platform; and optionally providing audit report of the encrypted file storage and access. A smart wallet with a group key using multiple signatures based on receipt of a threshold number of signatures. Split-key authentication by splitting the private key into two or more parts; and assigning the split private key part to two or more client devices.

The invention discloses an attribute-based ciphertext searching system and method in support of proxy re-encryption. According to the method, two functions that a user securely carries out searching and effectively shares searching authority in a cloud environment are realized at the same time. According to the method, through adoption of an LSSS linear secret sharing scheme, an attribute of an access user can be described in fine granularity, and the relatively high computing efficiency is achieved. In a threshold generation phase, a blind technology is carried out on a user key through utilization of a random value, and then the user key is submitted to a cloud server, so the confidentiality and security of the user key are ensured. A searching authority entrusting problem when an authorization user is offline in practical application is taken into consideration. A proxy re-encryption technology is imported, and the cloud server converts a ciphertext, so the encryption/decryption pressure of a data owner is migrated, and the system efficiency is greatly improved.

The invention relates to a data authorization deterministic update method based on proxy re-encryption for a cloud. The method is realized based on a system model, and the system model comprises a KGCserver, an RKM server, an RKG server and an RE-Enc server; the method comprises the following steps of establishing a system; creating data; generating proxy re-encryption key parameters; generatingciphertext data with authorization information; obtaining the ciphertext data; carrying out re-encryption ciphertext decryption by a user; and updating authorization deterministic. According to the method, the proxy re-encryption is introduced into the cloud data sharing and authorization update, and authorization management of the data is carried out by managing a re-encryption key; and the key management difficulty and the calculation amount of the user during data sharing and authorization management are reduced, and meanwhile, the re-encryption key is segmented and managed, and the deterministic update of the key is realized when the authorization is changed.

The invention discloses a certificateless-condition-based proxy re-encryption system and method. A certificateless public key system and a proxy re-encryption system are combined together, so that certificate management is avoided and problems in secrete key distribution and escrow are eliminated. In a condition of ensuring encryption safety, online re-encryption is performed flexibly and the re-encryption capability of a proxy center is controlled, so that only ciphertext meeting specific conditions can be re-encrypted effectively. At the same time, since the certificateless public key system is used, the system and method provided by the invention have advantages of traditional public key encryption and identify-based encryption and are good in performance and convenient in application in an open network environment. The novel system and method provided by the invention are safe and efficient.

A proxy-based encryption method includes generating, according to a private key of a sending end and a public key of a receiving end, proxy keys that correspond to at least two proxy servers, respectively. The number of the proxy keys is equal to the number of the proxy servers. The method further includes sending encrypted ciphertexts and the proxy keys that correspond to the at least two proxy servers respectively to the at least two proxy servers, respectively, so that the at least two proxy servers re-encrypt the encrypted ciphertexts according to the corresponding proxy keys.

The invention discloses an encrypted image retrieval method supporting multiple keys. The invention utilizes proxy re-encryption technology to convert different image encryption keys into the form that the inquiry user can decrypt with his private key, applies local sensitive hash algorithm to pre-classify the image set, improves the retrieval speed, and then encrypts the image feature vector withthe safe nearest neighbor algorithm to improve the retrieval precision. The invention supports a query user to query image sets from different encryption keys by using a query trap under a multi-keyscenario, and the user can only decrypt the query result by using a legal private key. The invention can protect data privacy and safety, and the cloud server cannot obtain any plaintext information from the ciphertext set, the index set and the ciphertext key set, nor can it obtain any plaintext information from the query trap. The invention is efficient and feasible in practical application.

The invention relates to a semantic searchable encryption method for proxy re-encryption resistant to a post quantum attack. According to the method, synonym extension is performed on a search keyword input by a user, so that relative keywords semantically similar to the original input keyword can be found, extension query is beneficial to matching more relative documents, and flexibility of search can be effectively enhanced; search permission proxy can be supported via a proxy re-encryption mechanism; a data owner utilizes unidirectional proxy re-encryption to consign own search permission to the other user, the consignee can search encrypted data of the consignor, and the consignor cannot search the data of the consignee; the function of resisting the post quantum attack is achieved by a lattice-based password technology, and security of cloud storage is improved. According to the scheme of the method provided by the invention, the problems that existing searchable schemes are low in query efficiency, limited in search permission and unable to resist quantum attack are effectively solved.

The present invention discloses a multiple users-based outsourcing database audit method, aiming to solve problems of low signature verification efficiency and complex decryption in the prior art. The method comprises a first step that a data owner encrypts data by using a proxy re-encryption method so as to form a second-level ciphertext, generates a re-encryption secret key by inquiring a public key of a user, generates a searching label by using an Evdokimov encryption manner, and generates hash tree root signature by using aggregate signature; and the signature, second-level ciphertext, re-encryption secret key and the searching label are transmitted to a cloud server; a second step that the cloud server encrypts the second-level ciphertext so as to generate a first-level ciphertext; a third step that a user sends a search request to the cloud server, and the cloud server searches and returns a corresponding first-level ciphertext; and a fourth step that the user decrypts the first-level ciphertext so as to form a plaintext, and performs aggregate verification on the plaintext. Through adoption of the method, the burden on the data owner is greatly reduced, interaction is reduced for one time, data privacy protection is improved, and the method can be applied to safe data outsourcing in a cloud calculation environment.

The invention provides a CCA secure proxy re-encryption method with delegable verifiability and is used for solving the problem that in the prior art, an encryption method is insufficient in security. The method comprises the realization steps that a data owner generates a system parameter and calculates own public key and private key; a data receiver calculates own public key and private key; the data owner carries out second-layer ciphertext encryption on a plaintext, uploads a result to a cloud server, moreover calculates a re-encryption key and sends the re-encryption key to the cloud server; the cloud server carries out composite encryption on a second-layer ciphertext, signs the result, moreover, calculates a signature verification key and sends the second-layer ciphertext, a public key encrypted ciphertext, a signature value and the signature verification key to the data receiver; the data receiver sends the received data and the public key encrypted private key to a client; the client carries out legality verification on the public key encrypted ciphertext; the client carries out integrity and legality verification on a re-encrypted ciphertext; and the data receiver decides whether to decrypt the ciphertext or not according to verification results.

The invention discloses a data broadcasting distribution protection method based on proxy re-encryption and security chips. The method includes that a data user adopts a general-purpose computer system provided with the security chips as computing equipment, before data is distributed, a data owner and the data user agree upon public security parameters and cryptology algorithms of both sides and the security chips acquire encryption keys, the data owner generates a data encryption packet, binds configuration requirements for hardware to the data encryption packet and then broadcasts the data encryption packet to a public channel, and the data user acquires the data encryption packet from the public channel, the security chips checks the configuration of the computer system, if the configuration requirements are met, the data encryption packet is re-encrypted and then the data user decrypts the re-encrypted data, and if the configuration requirements are not met, the decryption is rejected. The data broadcasting distribution protection method based on the proxy re-encryption and the security chips can ensure that a computing platform of the data user can obtain and use the distributed data only when specific configuration is met, the protection strength is strong, and the implementation cost is low.

The invention discloses a group key distribution method for machine-type communication based on proxy re-encryption. The problem of network signaling jam and server overload in the prior art is mainly solved. The distribution method is realized through the following steps: 1, generating a system parameter; 2, generating and distributing public and secret keys; 3, generating a re-encryption key; 4, obtaining a ciphertext; 5, sending a message to a proxy gateway; 6, receiving the message by the proxy gateway; 7, generating and broadcasting a re-encrypted ciphertext; 8, receiving a broadcast message; and 9, decoding the re-encrypted ciphertext to obtain a group key. According to the invention, through proxy re-encryption, the re-encrypted ciphertext is generated and broadcasted by utilization of the proxy gateway, and the problem, of network signaling jam and server overload, generated during key distribution of a machine-type communication server and a machine-type communication equipment group is relieved. The method is applicable to a machine-type communication network.

The invention discloses a ciphertext retrieval system and method for supporting proxy re-encryption in combination with identity and attribute. The method realizes sharing of a secure and efficient one-to-many user search authority in a cloud environment. The previous identity-based searchable encryption and proxy scheme combines identity-based proxy re-encryption with a searchable encryption scheme to implement agency for a one-to-one search authority. The scheme uses an identity-based encryption method in the initial ciphertext encryption, and adopts an LSSS linear secret shared matrix access structure in the re-encryption phase, which can authorize the ciphertext retrieval authority to other users who conform to the access structure. Therefore, the scheme supports the sharing of a moregranular user search authority and has higher computational efficiency. In the re-encryption threshold generation phase, the user key is blinded by the random value and submitted to a cloud server, ensuring the confidentiality and security of the user key.

Disclosed is an orthogonal access control system based on cryptographic operations provided by multi-hop proxy re-encryption (PRE) that strictly enforces only authorized access to data by groups of users, scalable to large numbers of users. Scalable delegation of decryption authority can be shared with a plurality of members of a group whether those members be users or devices, and members of a group can further create sub groups and delegate decryption authority to those members, whether users or devices. Members are granted access via generation of transform keys, and membership or access can be revoked merely be deleting the transform key—no elimination of the encrypted data, regardless of its storage location, is needed.

The invention discloses a multi-user file sharing control method in a cloud environment. The method utilizes an NTRU algorithm and a proxy re-encryption technology, proposes an efficient and safe multi-user shared file control scheme, and implements more fine-grained delegate control of a file owner on a shared file. The method mainly comprises parts of key generation, encryption, proxy re-encryption and decryption. When a ciphertext storage space is reduced, the method only needs to carry out addition, subtraction, multiplication and modular operations, calculated quantities of file encryption and decryption are only in linear increasing relationship with a multiplication operation of a number of file blocks, and after the file owner authorizes, file sharing users can access respective different file block contents. The multi-user file sharing control method disclosed by the invention has the advantages of resistance to a quantum calculation attack, low calculation cost and low communication traffic, and is more suitable for an environment in which client calculation resources and communication resources are limited.