Cryptographically secure and privacy-preserving matching

Abstract

This disclosure relates to protecting the security and privacy of data, including user identifiers (IDs). In some aspects, a method includes receiving, by a cryptographically-secure private set intersection (CSPSI) server and from a first device corresponding to a first entity, a first identifier retrieval request corresponding to a digital component request being sent from the first device to a second device corresponding to a second entity. The first identifier retrieval request includes a first encrypted user identifier generated by encrypting a user identifier for a user using a first encryption key corresponding to the first entity. The CSPSI server determines, using the encrypted user identifier, a bilateral encrypted user identifier for the user generated by encrypting the first encrypted user identifier using a second encryption key corresponding to the second entity. The CSPSI server sends the bilateral encrypted user identifier for the user to the first device.