Secret Key Generation With Cross Multiplication of Two-Way Random Signals

Liang Jin,Yangming Lou,Shengjun Zhang,Xiaoming Xu,Zhou Zhong

doi:10.1109/access.2019.2935206

Liang Jin, Yangming Lou + Show 3 more

Open Access

https://doi.org/10.1109/access.2019.2935206

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Journal: IEEE Access	Publication Date: Jan 1, 2019
Citations: 16	License type: CC BY 4.0

Affiliation: PLA Information Engineering University

Abstract

The secret key generation rate (SKGR) of current physical layer security methods is not high enough for practical requirements. A novel SKG method based on the cross multiplication (XM) of two-way random signals is proposed for TDD-MIMO system. The principle concealed beneath the XM method is found that the XM operation not only derives the common random source for both legitimate partners, but also employs new generated cross-terms due to bilinear operation to provide more measurements of the random source and more secret keys accordingly, which is essentially superior to the existing paired multiplication (PM) method. Then, the theoretical SKGR of two-way random signals is analyzed and it is validated that SKGR is determined by the randomness of the reciprocal channel and the two-way secure transmission rates collectively. Furthermore, SKGR of XM and PM methods are derived in closed-form respectively under infinite antenna condition and the former shows a linear increase with the channel coherence interval, which are also approximately valid for finite antenna. The innovative conclusion means the slow-changing property of some channel environments can be further exploited and the proposed XM method can be applied to solve the low SKGR problem in static or quasi-static channel environment such as IoT. Finally, the simulations verify the theoretical results and show that the XM method achieves several orders of magnitude higher SKGR than the PM method.

Highlights

Wireless communications are vulnerable to being attacked due to the inherent broadcast nature of radio propagation [1]
Considering that the equal power allocation is optimal and the paired multiplication (PM) common random source implies the condition of equal time allocation, so we choose equal allocation strategy to maximize the practical secret key generation rate (SKGR) and compare the two secret key generation [6] (SKG) methods
The Lilliefors test is performed to verify that the Gaussian distribution approximately holds at limited antenna number and further evaluate the performance improvement of proposed SKG method

Summary

Introduction

Wireless communications are vulnerable to being attacked due to the inherent broadcast nature of radio propagation [1]. Encryption and authentication based on symmetric-key are important measures to ensure the security of wireless network, where the critical issue is how to distribute secret keys to the legitimate partners without leaking any information to the eavesdroppers [2]. Some computational complexity based methods are developed, such as DiffieHellman key exchange protocol, which works on the assumption that the eavesdroppers are unable to solve a certain mathematical problem in feasible time [3]. It is not clear whether these methods are still valid with the development of quantum computer [4].

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Results

Conclusion