2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/169791We propose a new quantum key distribution (QKD) protocol based on the fully quantum mechanical states of the Faraday rotators. The protocol is unconditionally secure against collective attacks for multi-photon source up to two photons on a noisy environment. It is also robust against impersonation attacks. The protocol may be implemented experimentally with the current spintronics technology on semiconductors.7 pages, 7 EPS figuresQuantum Physicstext