Jamming Based on an Ephemeral Key to Obtain Everlasting Security in Wireless Environments

TL;DR

This paper introduces a jamming method using ephemeral keys to achieve everlasting security in wireless communications, even against powerful eavesdroppers with advanced hardware, by exploiting receiver vulnerabilities and combining frequency hopping.

Contribution

The paper proposes a novel jamming technique leveraging ephemeral keys to convert cryptographic secrets into information-theoretic secure bits in wireless environments.

Findings

Achieves positive secrecy rates even with perfect eavesdropper access.

Effective in wideband systems with frequency hopping.

Maintains security despite advanced eavesdropper hardware capabilities.

Abstract

Secure communication over a wiretap channel is considered in the disadvantaged wireless environment, where the eavesdropper channel is (possibly much) better than the main channel. We present a method to exploit inherent vulnerabilities of the eavesdropper's receiver to obtain everlasting secrecy. Based on an ephemeral cryptographic key pre-shared between the transmitter Alice and the intended recipient Bob, a random jamming signal is added to each symbol. Bob can subtract the jamming signal before recording the signal, while the eavesdropper Eve is forced to perform these non-commutative operations in the opposite order. Thus, information-theoretic secrecy can be obtained, hence achieving the goal of converting the vulnerable "cheap" cryptographic secret key bits into "valuable" information-theoretic (i.e. everlasting) secure bits. We evaluate the achievable secrecy rates for different settings, and show that, even when the eavesdropper has perfect access to the output of the transmitter (albeit through an imperfect analog-to-digital converter), the method can still achieve a positive secrecy rate. Next we consider a wideband system, where Alice and Bob perform frequency hopping in addition to adding the random jamming to the signal, and we show the utility of such an approach even in the face of substantial eavesdropper hardware capabilities.