Two-party Models and the No-go Theorems

Abstract

In 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.