Multi-Party Private Set Intersection Using Elliptic Curve Keys
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Solution Overview
Problem
Existing multi-party private set intersection protocols lack a secure and efficient solution using elliptic curve cryptography, leading to high network bandwidth and hardware requirements, and immature homomorphic encryption issues.
Innovation Solution
A data determination method utilizing elliptic curve cryptography for encrypting data between multiple terminal devices, employing public keys to determine intersection data without relying on mature symmetric cryptography primitives, thereby reducing network bandwidth and improving security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional finite-field cryptography is used for multi-party private set intersection, then security level is maintained, but key length is longer and network bandwidth requirements are higher
Solution Approach 1:
The patent changes the cryptographic parameter system from conventional finite-field cryptography to elliptic curve cryptography. This parameter change allows achieving the same security level (e.g., 128-bit security) with significantly shorter key lengths - elliptic curve keys are approximately one-quarter the length of conventional RSA keys for equivalent security, directly resolving the contradiction between security level and key length
2Reliability
If homomorphic encryption is used for multi-party private set intersection, then security is enhanced, but hardware requirements become higher and the technology remains immature
Solution Approach 1:
The patent extracts the heavy computational burden from the multi-party computation process by using elliptic curve cryptography operations that can be efficiently performed on standard hardware. The protocol design separates the cryptographic operations from complex homomorphic encryption operations, extracting only the essential encryption/decryption functions that can be implemented with mature, low-hardware-complexity elliptic curve algorithms while maintaining security
3Ease of manufacture
If symmetric cryptography primitives are used, then implementation is simpler, but network bandwidth requirements increase
Solution Approach 1:
The patent applies asymmetry by using asymmetric encryption (elliptic curve cryptography) instead of symmetric cryptography. In the protocol, each party generates public-private key pairs where public keys are distributed openly and private keys remain secret. This asymmetric approach allows parties to encrypt data for others using their public keys without requiring secure key exchange channels, reducing network bandwidth requirements while maintaining implementation feasibility through well-established elliptic curve algorithms
Data Source
AI summary
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.