Security in Asynchronous Interactive Systems

Secure function computation has been thoroughly studied and optimized in the past decades. We extend techniques used for secure to simulate arbitrary protocols involving a mediator. The key feature of our notion simulation is that it bidirectional: not only does produce outputs could happen original protocol, but produces all such outputs. In synchronous system, can be shown this requirement already achieved by standard computation. However, an asynchronous new subtleties arise because scheduler influence output. provide construction if $n > 4t$, where $t$ number malicious agents, which provably best possible. also show satisfies additional security properties even $3t < n \le 4t$.