Error-free message transmission in the universal composability framework

Abstract

This thesis introduces models for error-prone communication channels and functionalities for error-free communication in the Universal Composability framework. Realizing these functionalities enables protocols to make use of cryptographic error-correcting schemes which are more powerful than classical codes. First, we define new ideal functionalities TrCLOSE and FCWT to model error-prone communication channels. Then, we define four different ideal functionalities for error-free message transmission, each providing successively stronger message delivery guarantees. Using ideal message certification, we give protocols which realize three of these functionalities for error rates up to 1/2. Finally, we prove that the fourth functionality, which models error-free data storage, is not realizable if the error rate exceeds 1/4.