Federated data query methods and apparatuses based on privacy preserving

A non-transitory, computer-readable medium storing one or more instructions executable by a computer system to perform operations for federated data query by a third party device to securely query target data from a federated data table of a plurality of data parties, wherein the federated data table is an attribute ciphertext data table created based on federated attribute data of the plurality of data parties for multiple service subjects, and the operations are performed by the third party device and comprises:

• obtaining multiple associated index points of a query target based on comparison between a ciphertext of the query target and ciphertexts of a plurality of index points corresponding to a first attribute column, wherein each index point corresponding to the first attribute column is a data segmentation point for indexes created based on attribute value sorting of the first attribute column, and the query target comprises a query value in the first attribute column;
• obtaining a coded ciphertext of each of row identifiers corresponding to the multiple associated index points, wherein a row identifier of each row is determined through row coding for an out-of-order data table pre-obtained by disordering the federated data table;
• restoring a corresponding coded ciphertext to a plaintext row identifier, to determine a candidate row from the out-of-order data table;
• and
• comparing a ciphertext of an attribute value of each of candidate rows in the first attribute column with the ciphertext of the query target, to determine a target row from the candidate rows to obtain target data in the target row.

A computer-implemented apparatus, comprising:

• one or more computers;
• and
• one or more computer memory devices interoperably coupled with the one or more computers and having tangible, non-transitory, machine-readable media storing one or more instructions that, when executed by the one or more computers, perform one or more operations for federated data query by the computer-implemented apparatus to securely query target data from a federated data table of a plurality of data parties, wherein the federated data table is an attribute ciphertext data table created based on federated attribute data of the plurality of data parties for multiple service subjects, and the one or more operations comprise:
• obtaining multiple associated index points of a query target based on comparison between a ciphertext of the query target and ciphertexts of a plurality of index points corresponding to a first attribute column, wherein each index point corresponding to the first attribute column is a data segmentation point for indexes created based on attribute value sorting of the first attribute column, and the query target comprises a query value in the first attribute column;
• obtaining a coded ciphertext of each of row identifiers corresponding to the multiple associated index points, wherein a row identifier of each row is determined through row coding for an out-of-order data table pre-obtained by disordering the federated data table;
• restoring a corresponding coded ciphertext to a plaintext row identifier, to determine a candidate row from the out-of-order data table;
• and
• comparing a ciphertext of an attribute value of each of candidate rows in the first attribute column with the ciphertext of the query target, to determine a target row from the candidate rows to obtain target data in the target row.