Secure Communication In Stochastic Wireless Networks With The Aid Of Jamming

Security systems for wireless networks based on cryptographic primitives generally ignore the physical properties of the wireless medium and the spatial configuration of nodes. These two factors are important since they affect the communication channels between nodes, which in turn determine the fundamental secrecy limits of wireless networks. The inherent randomness associated with the wireless channel and the spatial location of the nodes can be leveraged to provide intrinsic security at the physical-layer level. More recently, there has been a renewed interest in information-theoretic security over wireless channel. A fundamental limitation of this research is that it only considers scenarios with a small number of nodes. To account for large-scale networks composed of multiple legitimate and eavesdropper nodes, the intrinsically secure communications graph, i S-graph is introduced from a geometrical perspective and an information-theoretic perspective. The i S-graph is a random graph which describes the connections that can be securely established over a wireless network by exploiting the physical properties of the wireless medium.Secrecy capacity of the i S-graph can be increased by reducing the signal-to-interference-plus-noise-ratio(SINR) of the eavesdroppers via controlled interference. Interference then emerges as a valuable resource for wireless security, and can be used by the legitimate nodes to increase the noise level of the eavesdropper to ensure higher secure communication rates.Inspired by recent results on information-theoretic security, this paper considers the transmission of secret messages over wireless networks in which the legitimate communication nodes are aided by cooperative jamming nodes, and proposes a model of a secure communication graph with jamming, namely, j S-graph, on the basis of i S-graph. This paper aims to characterize the security properties of the j S-graph in the protocol model and the threshold model. The results show that, with the aid of jamming, the secure communication graph can lead to significant secrecy gains compared to its counterpart i S-graph without the aid of jamming. Then, jamming strategies to handle unknown eavesdropper locations are proposed. These results help us to clarify how the presence of eavesdroppers and the cooperative jamming can influence secure connectivity in wireless networks.