2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/117099In this paper, we reconsider the communication model used in the no-go theorems on the impossibility of quantum bit commitment and oblivious transfer. We state that a macroscopic classical channel may not be replaced with a quantum channel which is used in the reduced model proving the no-go theorems. We show that in some restricted cases, the reduced model is insecure while the original model with a classical channel is secure.9 pages, 8 figures. Due to attacks received from reviewers, an important case-study on "coin-flipping-based protocols" is removed. Comments are welcomeQuantum Physicstext