This document summarizes a research paper about using past-future entanglement for quantum cryptography. It discusses how past-future entanglement allows two qubits to become entangled without interacting directly by interacting with a vacuum field at different times. The document proposes that this method could be used for secure communication, as an eavesdropper disturbing the field would break the entanglement and be detected. It suggests past-future entanglement could support quantum teleportation through time and secure key distribution, though realizing it practically requires further research.