SMOCK: A Scalable Method of Cryptographic Key Management For Mission-Critical Networks

In this paper, we study challenges and possible solutions to cryptographic key management in mission-critical networks. Existing symmetric key cryptography mechanisms do not scale well when supporting end-to-end secure and private communication. Existing public key cryptography mechanisms in self-organized ad hoc networks cannot resist a Sybil attack, where a single malicious node presents multiple identities to control a substantial fraction of a network. In this paper, we present a new paradigm of public key cryptography based on combinatorial design, called SMOCK, where nodes combine more than one key to encrypt and decrypt each message. Our key allocation scheme guarantees that a set of keys held by one user is not a subset of keys held by any other user. We show that our proposed method offers efficiency in memory usage, control data exchange, as well as controllable resilience against node captures.