US 12,149,604 B2
Practical sorting on large-scale encrypted data
Jung Hee Cheon, Seoul (KR); and Seungwan Hong, Seoul (KR)
Assigned to Crypto Lab Inc., Seoul (KR); and Seoul National University R&DB Foundation, Seoul (KR)
Appl. No. 17/616,349
Filed by Crypto Lab Inc., Seoul (KR); and Seoul National University R&DB Foundation, Seoul (KR)
PCT Filed Jun. 5, 2020, PCT No. PCT/KR2020/007350
§ 371(c)(1), (2) Date Dec. 3, 2021,
PCT Pub. No. WO2020/246848, PCT Pub. Date Dec. 10, 2020.
Claims priority of provisional application 62/857,617, filed on Jun. 5, 2019.
Claims priority of application No. 10-2020-0036119 (KR), filed on Mar. 25, 2020.
Prior Publication US 2022/0255722 A1, Aug. 11, 2022
Int. Cl. H04L 9/00 (2022.01); H04L 9/06 (2006.01)
CPC H04L 9/008 (2013.01) [H04L 9/06 (2013.01); H04L 2209/125 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method for processing homomorphic ciphertexts, the method comprising:
receiving an input of an instruction for sorting a plurality of homomorphic ciphertexts;
sorting the homomorphic ciphertexts by using a 5-way sorter which can sort five homomorphic ciphertexts in a single stage; and
outputting the sorted homomorphic ciphertexts, wherein the 5-way sorter is configured to:
based on a first homomorphic ciphertext, a second homomorphic ciphertext, and a third homomorphic ciphertext being input, and using a comparison function between two input values, calculate a larger value and a smaller value between the first homomorphic ciphertext and the second homomorphic ciphertext,
input the larger value and the third homomorphic ciphertext into the comparison function and output a first output value,
input the smaller value and the third homomorphic ciphertext into the comparison function and output a third output value, and
calculate a second output value by subtracting the first output value and the third output value from a summed-up value of the first to third homomorphic ciphertexts and output the second output value.