US 12,362,906 B2
Apparatus for privacy preserving text search using homomorphic encryption and method thereof
Garam Lee, Seoul (KR); and Junbum Shin, Suwon-si (KR)
Assigned to CRYPTO LAB INC., Seoul (KR)
Filed by CRYPTO LAB INC., Seoul (KR)
Filed on Sep. 8, 2023, as Appl. No. 18/463,556.
Claims priority of application No. 10-2022-0114120 (KR), filed on Sep. 8, 2022; and application No. 10-2023-0084386 (KR), filed on Jun. 29, 2023.
Prior Publication US 2024/0097878 A1, Mar. 21, 2024
Int. Cl. H04L 9/00 (2022.01); G10L 15/26 (2006.01); H04L 9/08 (2006.01); H04L 9/40 (2022.01)
CPC H04L 9/008 (2013.01) [G10L 15/26 (2013.01); H04L 9/0825 (2013.01); H04L 63/0442 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A text search method in an electronic apparatus, the method comprising:
based on a query including a text being input, computing a vector value having a preset size by using a preset encoding algorithm, the vector value corresponding to the text;
generating a query ciphertext by homomorphic encryption for the computed vector value;
transmitting the generated query ciphertext to a server;
receiving a calculation result ciphertext having similarity information with the query for each of a plurality of indexes;
determining an index having a preset similarity by restoring the calculation result ciphertext; and
receiving information corresponding to the index by transmitting the determined index to the server;
wherein the generating the query ciphertext comprises, based on the text being composed of a plurality of sentences, computing a vector value in a unit of a plurality of sentences, homomorphically encrypting each of the vector values generated in the unit of sentences, and sequentially inserting each of the homomorphically encrypted vector values into each of a plurality of slots in the homomorphic ciphertext to generate a query ciphertext.