Huazhong University of Science and Technology

Yubo Zheng

Hai Jin

Wei Wang

Peng Xu

Tianyang Chen

Yinjia Pi

Shuning Xu

A method and system for automatic deletion of information based on time synchronization and trusted counting is provided, the method including: defining different data structures including configurations in a normalized manner; setting triggering conditions for automatic information deletion, including conditions for automatic deletion based on time synchronization and/or based on trusted counting; maintaining synchrony of the configurations across different domains; and after satisfying the triggering conditions, making an information source domain and/or an information propagation domain perform the automatic information deletion. Considering that existing data deletion mechanisms cannot delete information according to preset retention periods, the present application employs synchrony across system clocks to perform automatic deletion of authorization information under circulation after a certain time period, and further limits a circulation count for information of interest so as to ensure that the information and its copies are all deleted after reaching a preset maximum permittable circulation count.

Method and system for automatic deletion of information based on time synchronization and trusted counting

A method for increasing the difficulty for attackers to launch keyword guessing attacks, which uses a time-delay encryption with a keyword search based on a public key that generates searchable ciphertexts and/or files ciphertexts for keywords of at least one file that uploaded by time-delay encryption from a cloud server. A system for implementing the method is also described.

Method of time-delay encryption with keyword search and system using the same

The present invention relates a method for ensuring search completeness of searchable public key encryption, applicable to a blockchain network formed by a plurality of computer nodes. The method at least comprises: the blockchain network receiving a keyword ciphertext and a corresponding file-identifier ciphertext generated by a transmitting end based on the public key encryption, and at least one miner storing the ciphertexts in a ciphertext table; the blockchain network receiving a search trapdoor Ttransmitted by a receiving end, generated according to a private key and a keyword w to be searched; the at least one miner in the blockchain network performing a secure search based on information of a state table and the search trapdoor T, and outputting a search result to the blockchain network; and the blockchain network feeding the search result back to the receiving end. The invention uses the blockchain technology to solve the long-standing search completeness problem in searchable public key encryption, and the proposed method has universality.

Method and system for ensuring search completeness of searchable public key encryption

The present invention relates to a method and a system for robust, searchable, symmetrical encryption, the method comprising: during initialization, having a retrieval server perform retrieval on stored ciphertext information according to a searchable ciphertext and retrieval trapdoor information (Cnt, K, Loc) sent by a client, wherein, the retrieval server acquires a last received first ciphertext set Cfrom a ciphertext database CDB just before the present retrieval according to a retrieval key K and an encryption counter Cntsent by the client, acquiring a second ciphertext set Cin a retrieval request history from a cache ciphertext database GRP according to a cache ciphertext index Loc, and merging the first ciphertext set Cand the second ciphertext set Cto form a retrieval set, and sending it to the client for decryption. The present invention is able to improve retrieval performance of searchable symmetrical encryption algorithm with robust forward and backward secrecy and to make searchable symmetrical encryption algorithm more practical.

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Wuhan, China

Yubo Zheng