4 results about "Pseudorandom permutation" patented technology

The invention relates to the technical field of information security, in particular to a searchable encryption method and system based on an sm4 algorithm, and the method comprises the steps: key generation: generating a first key and a second key; index construction: constructing an inverted index dictionary based on the data set; key word encryption: carrying out encryption replacement on key words in the reverse index by using the first key; node encryption and filling: encrypting the nodes in the inverted record tables by using the second key, and filling all the inverted record tables to be equal in length; trap door generation: respectively executing first key encryption and second key encryption on the query keyword to generate a search trap door; and searching and matching: carrying out matching retrieval in the encrypted inverted index by utilizing the search trap door, and outputting a corresponding encrypted document identifier. According to the method, through collaborative design of SM4 double-key encryption, pseudo-random permutation, equal-length filling and a trap door retrieval mechanism, high-security storage of cloud data and efficient retrieval under the ciphertext condition are achieved.

This application discloses a file processing method, an electronic device, and a storage medium. The file processing method includes: determining a first identifier vector for a file based on its position in a file set; generating a first storage location for storing the first identifier vector based on a hash function and the file's feature vector; determining a second identifier vector based on the hash table corresponding to the hash function and the first identifier vector; and storing the second identifier vector in a second storage location obtained by performing a pseudo-random permutation on the first storage location. The second storage location is used to locate the first storage location corresponding to the feature vector of the file to be searched when searching for a file. Thus, based on the second storage location and the position of the file to be searched in the file set, the corresponding file can be found without requiring the user to provide precise keywords for the search, thereby improving file search efficiency.

The invention discloses a block chain-based federated learning system external privacy protection method and system, an electronic device and a storage medium. The method comprises the steps of adding noise to local model parameters by each participant within a specified time; an encrypted address is randomly generated and sent to each participant, and each participant sends the local model parameters added with the noise to the encrypted address and then carries out data confusion processing; verifying the noise-added and confused local model parameters, and participating in global model parameter aggregation of the round after the verification is passed; performing encryption by using the ID and the public key of each participant, performing independent encryption on the ID at the same time, generating an encryption index table, disorganizing a data sequence in the table by using a pseudo-random permutation function, and writing the data into a block; and each participant downloads and decrypts the encrypted ID by using the private key, and downloads and decrypts the ciphertext if the ID is verified to be correct. According to the method provided by the invention, the security of the cryptography level is met, the attack of external opponents can be effectively resisted, and the external privacy security of the system is realized.

An example method includes receiving metadata associated with a plurality of computing devices. Each metadata includes an indication of a cryptographic fingerprint of secret data known to an associated computing device. The method includes receiving, over a short-range wireless communication mode, a ciphertext message broadcast by another computing device. The message is generated by an encryption algorithm that has the secure pseudo-random permutation (PRP) property and that conforms the message to a constrained packet size associated with the communication mode. A cryptographic fingerprint is derivable from the message. The method includes generating the cryptographic fingerprint. The method includes comparing the generated fingerprint with fingerprints associated with previously received metadata. The method includes, upon a determination that the generated fingerprint matches a fingerprint associated with one of the previously received metadata, establishing an integrity of the message. Establishing of the integrity is based on the PRP property of the encryption algorithm.