Secret Key Generation via Pulse-Coupled Synchronization

TL;DR

This paper introduces a new method for secret key generation in wireless networks using pulse oscillator synchronization, leveraging natural phase differences and network synchronization times, with security against eavesdroppers and jammers.

Contribution

It proposes a novel pulse-coupled synchronization framework for secret key sharing, deriving entropy bounds and analyzing security against passive eavesdroppers and active jammers.

Findings

Entropy bounds for two-user systems derived

Secret key rate bounds considering propagation delays

Protocol resilience to active jamming demonstrated

Abstract

A novel framework for sharing common randomness and generating secret keys in wireless networks is considered. In particular, a network of users equipped with pulse oscillators (POs) and coupling mechanisms in between is considered. Such mechanisms exist in synchronized biological and natural systems, and have been exploited to provide synchronization in distributed networks. We show that naturally-existing initial random phase differences between the POs in the network can be utilized to provide almost identical common randomness to the users. This randomness is extracted from the synchronization time in the network. Bounds on the entropy of such randomness are derived for a two-user system and a conjecture is made for a general $n$-user system. Then, a three-terminal scenario is considered including two legitimate users and a passive eavesdropper, referred to as Eve. Since in a practical setting Eve receives pulses with propagation delays, she can not identify the exact synchronization time. A simplified model is then considered for Eve's receiver and then a bound on the rate of secret key generation is derived. Also, it is shown, under certain conditions, that the proposed protocol is resilient to an active jammer equipped with a similar pulse generation mechanism.