Relationship of three cryptographic channels in the UC framework

This paper shows that three cryptographic channels, secure channels (SC), anonymous channels (AC) and direction-indeterminable channels (DIC), are reduced to each other in the UC (universally composable) framework. We first define ideal functionalities for these channels, F_SC, F_AC and F_DIC. We then prove that a SC protocol UC-realizes F_SC in the F_DIC -hybrid model, that a DIC protocol UC-realizes F_DIC in the F_AC-hybrid model, and that a AC protocol UC-realizes F _AC-hybrid model in the F_SC-hybrid model