This document describes a three-party cryptographic handshake protocol in a wireless network in which a sighter receives, from a beacon, a packet including an exponentiation of a random value and a proxy value and generates an end-to-end encrypted ephemeral identifier (E2EE-EID) from the exponentiation of the random value and the proxy value. The sighter generates a message for an owner, selects a private key, and computes an exchanged key using the private key and the E2EE-EID. The sighter extracts a common symmetric key from the exchanged key, encrypts the message using the common symmetric key, and transmits the encrypted message to the owner.