Secure Communication in an Unknown Network Using Certificates

We consider the problem of secure communication in a network with malicious (Byzantine) faults for which the trust graph, with vertices the processors and edges corresponding to certiied public keys, is not known except possibly to the adversary. This scenario occurs in several models. For example, in survivability models in which certifying authorities may be corrupted, or in networks which are being constructed in a decentralized way. We present a protocol with which secure communication can be achieved in this case, provided the trust graph is suuciently connected.