2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/144587A method is given to detect the presence of eavesdroppers when a noisy message is sent to a privileged receiver. A proof of the effectiveness if this method is demonstrated, and a comparison is made to other quantum cryptographic tasks.21 pages, 1 figure. Submitted to Quantum Information & Computation journalQuantum Physicstext