Visa Inc.
Efficient concurrent scalar product calculation

Abstract:

A method and system for performing a calculation of a privacy preserving scalar product are provided. A first party and a second party (e.g., a first computer and a second computer) possessing a first vector and a second vector respectively, can concurrently determine the scalar product of the two vectors, without revealing either vector to the other party. Each vector can be masked and then encrypted using a public key of an asymmetric key pair. Using homomorphic encryption operations, the scalar product of the vectors can be determined while the vectors are still encrypted. Each party can compare the scalar product, or a value derived from the scalar product against a predetermined threshold. As an example, two parties can perform the scalar product to compare two biometric templates expressed as vectors without revealing the biometric templates to one another, preserving the privacy of persons corresponding to those biometrics.