Systems and methods for multi-party private set intersection

Patent metadata

Field	Value
Publication number	US-12519640-B2
Application number	US-202318298296-A
Country	US
Kind code	B2
Filing date	Apr 10, 2023
Priority date	Apr 15, 2022
Publication date	Jan 6, 2026
Grant date	Jan 6, 2026

Abstract

Computer-implemented methods, apparatuses, storage media, and system are disclosed. In an example, a first terminal device sends first encrypted data to a second terminal device. The second terminal device encrypts the first encrypted data by using a second public key to obtain second encrypted data, and sends the second encrypted data and third encrypted data to the first terminal device. The first terminal device encrypts the third encrypted data by using a first public key to obtain fourth encrypted data, acquires first intersection data of the second encrypted data and the fourth encrypted data, and sends the first intersection data to a third terminal device. The third terminal device acquires fifth encrypted data from the first terminal device, determines second intersection data based on the fifth encrypted data and the first intersection data, and sends the second intersection data to the first terminal device and the second terminal device.

First claim

What is claimed is:

1 . A computer-implemented method, comprising:
sending, by a first terminal device, first encrypted data to a second terminal device, wherein the first encrypted data is obtained by the first terminal device by encrypting a first data set in the first terminal device by using a first public key; encrypting, by the second terminal device, the first encrypted data by using a second public key to obtain second encrypted data; sending, by the second terminal device, the second encrypted data and third encrypted data to the first terminal device, wherein the third encrypted data is obtained by the second terminal device by encrypting a second data set in the second terminal device by using the second public key; encrypting, by the first terminal device, the third encrypted data by using the first public key to obtain fourth encrypted data; acquiring, by the first terminal device, first intersection data of the second encrypted data and the fourth encrypted data; and sending, by the first terminal device, the first intersection data to a third terminal device.

2 . The computer-implemented method according to claim 1 , further comprising:
acquiring, by the third terminal device, fifth encrypted data from the first terminal device, wherein the fifth encrypted data is obtained based on a third data set in the third terminal device, the first public key, the second public key, and a third public key; and determining, by the third terminal device, second intersection data based on the fifth encrypted data and the first intersection data, and sending the second intersection data to the first terminal device and the second terminal device.

3 . The computer-implemented method according to claim 2 , before the sending, by a first terminal device, first encrypted data to a second terminal device, further comprising:
generating, by the first terminal device, the first public key by using elliptic curve parameter information; generating, by the second terminal device, the second public key by using the elliptic curve parameter information; and generating, by the third terminal device, the third public key by using the elliptic curve parameter information.

4 . The computer-implemented method according to claim 1 , wherein the sending, by the second terminal device, the second encrypted data and third encrypted data to the first terminal device comprises:
acquiring, by the second terminal device, first random sequence data corresponding to the second encrypted data; acquiring, by the second terminal device, second random sequence data corresponding to the third encrypted data; and sending, by the second terminal device, the first random sequence data and the second random sequence data to the first terminal device.

5 . The computer-implemented method according to claim 4 , wherein the encrypting, by the first terminal device, the third encrypted data by using the first public key to obtain fourth encrypted data, and the acquiring, by the first terminal device, first intersection data of the second encrypted data and the fourth encrypted data comprises:
encrypting, by the first terminal device, the second random sequence data by using the first public key to obtain third random sequence data; and acquiring, by the first terminal device, first intersection data of the first random sequence data and the third random sequence data.

6 . The computer-implemented method according to claim 2 , wherein the determining, by the third terminal device, second intersection data based on the fifth encrypted data and the first intersection data comprises:
encrypting, by the third terminal device, the first intersection data by using the third public key to obtain third intersection data; and acquiring, by the third terminal device, intersection data of the fifth encrypted data and the third intersection data to obtain the second intersection data.

7 . The computer-implemented method according to claim 2 , wherein the acquiring, by the third terminal device, fifth encrypted data from the first terminal device based on a third data set in the third terminal device comprises:
encrypting, by the third terminal device, the third data set in the third terminal device by using the third public key to obtain sixth encrypted data; sending, by the third terminal device, the sixth encrypted data to the second terminal device; encrypting, by the second terminal device, the sixth encrypted data by using the second public key to obtain seventh encrypted data; sending, by the second terminal device, the seventh encrypted data to the first terminal device; encrypting, by the first terminal device, the seventh encrypted data by using the first public key to obtain fifth encrypted data; and sending, by the first terminal device, the fifth encrypted data to the third terminal device.

8 . The computer-implemented method according to claim 2 , wherein the sending the second intersection data to the first terminal device and the second terminal device comprises:
acquiring, by the third terminal device, an arrangement order of data in the third data set; acquiring, by the third terminal device, plaintext data corresponding to the second intersection data from the third data set based on the arrangement order; and sending, by the third terminal device, the plaintext data corresponding to the second intersection data to the first terminal device and the second terminal device.

9 . A computer-implemented system, comprising:
one or more computers comprising a first computer, a second computer, and a third computer; 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 comprising:
sending, by the first computer, first encrypted data to the second computer, wherein the first encrypted data is obtained by the first computer by encrypting a first data set in the first computer by using a first public key;
encrypting, by the second computer, the first encrypted data by using a second public key to obtain second encrypted data;
sending, by the second computer, the second encrypted data and third encrypted data to the first computer, wherein the third encrypted data is obtained by the second computer by encrypting a second data set in the second computer by using the second public key;
encrypting, by the first computer, the third encrypted data by using the first public key to obtain fourth encrypted data;
acquiring, by the first computer, first intersection data of the second encrypted data and the fourth encrypted data; and
sending, by the first computer, the first intersection data to the third computer.

10 . The computer-implemented system according to claim 9 , wherein the one or more operations further comprise:
acquiring, by the third computer, fifth encrypted data from the first computer, wherein the fifth encrypted data is obtained based on a third data set in the third computer, the first public key, the second public key, and a third public key; and determining, by the third computer, second intersection data based on the fifth encrypted data and the first intersection data, and sending the second intersection data to the first computer and the second computer.

11 . The computer-implemented system according to claim 10 , wherein before the sending, by the first computer, first encrypted data to the second computer, the one or more operations further comprise:
generating, by the first computer, the first public key by using elliptic curve parameter infor

Assignees

• Alipay Hangzhou Inf Tech Co Ltd

Inventors

• Cui Jinming
• Duan Pu
• Wang Li

Classifications

• H04L63/0442 Primary

  wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption (cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30) · CPC title

• H04L63/0428

  wherein the data content is protected, e.g. by encrypting or encapsulating the payload · CPC title

• H04L9/30

  Public key, i.e. encryption algorithm being computationally infeasible to invert or user's encryption keys not requiring secrecy · CPC title

• H04L2209/46

  Secure multiparty computation, e.g. millionaire problem · CPC title

• G06F21/6245

  Protecting personal data, e.g. for financial or medical purposes · CPC title