Secure communication in an unknown network using certificates

Abstract

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 certified public keys, is not known except possibly to the adversary. This scenario occurs in several models, as for example in survivability models in which the certifyinga uthorities may be corrupted, or in networks which are being constructed in a decentralized way. We present a protocol that allows secure communication in this case, provided the trust graph is sufficiently connected.