US 12,438,696 B2
Copy-and-recurse operations for fully homomorphic encrypted database query processing
Hayim Shaul, Kfar Saba (IL); Guy Moshkowich, Nes Ziyona (IL); and Eyal Kushnir, Kfar Vradim (IL)
Assigned to International Business Machines Corporation, New York, NY (US)
Filed by International Business Machines Corporation, Armonk, NY (US)
Filed on Feb. 27, 2023, as Appl. No. 18/114,682.
Prior Publication US 2024/0297777 A1, Sep. 5, 2024
Int. Cl. H04L 9/00 (2022.01); G06F 16/2455 (2019.01)
CPC H04L 9/008 (2013.01) [G06F 16/24564 (2019.01)] 18 Claims
OG exemplary drawing
 
1. A computer-implemented method comprising:
generating, for a data set in a backend data store, a tree data structure comprising a hierarchy of nodes and edges connecting the nodes in a parent-child relationship;
in response to receiving an encrypted query from a client computing device, executing a search operation using the tree data structure at least by executing a copy-and-recurse computing tool to identify a portion of the tree data structure to which to apply a fully homomorphic encryption (FHE) operation, wherein the copy-and-recurse computing tool copies a subset of nodes of the tree data structure and recurses the search operation into the copied subset of nodes;
executing the FHE operation on a portion of the data set, corresponding to the identified portion of the tree data structure, to generate results of the FHE operation; and
outputting the results as an encrypted output to the client computing device,
wherein the subset of nodes of the tree data structure are child nodes that cross a specified range of the search operation, and wherein the copy-and-recurse computing tool copies the subset of nodes of the tree data structure and recurses the search operation into the copied subset of nodes at least by generating a copy-and-recurse matrix and multiplying a vector representing the child nodes of the tree data structure, that cross the specified range of the search operation, by the copy-and-recurse matrix.