2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/110638If an eavesdropper Eve is equipped with quantum computers, she can easily break the public key exchange protocols used today. In this paper we will discuss the post-quantum Diffie-Hellman key exchange and private key exchange protocols.11 pages, 2 figures. Submitted to SPIE DSS 2006; v2 citation typos fixed; v3 appendix typos correctedQuantum Physicstext