A Probing Model of Secret Key Generation Based on Channel Autocorrelation Function

Secret key generation(SKG)is a promising solution to the problem of wireless communications security.As the first step of SKG,channel probing affects it significantly.Although there have been some probing schemes,there is a lack of research on the optimization of the probing process.This study investigates how to optimize correlated parameters to maximize the SKG rate(SKGR)in the time-division duplex(TDD)mode.First,we build a probing model which includes the effects of transmitting power,the probing period,and the dimension of sample vectors.Based on the model,the analytical expression of the SKGR is given.Next,we formulate an optimization problem for maximizing the SKGR and give an algorithm to solve it.We conclude the SKGR monotonically increases as the transmitting power increases.Relevant mathematical proofs are given in this study.From the simulation results,increasing appropriately the probing period and the dimension of the sample vector could increase the SKGR dramatically compared to a yardstick,which indicates the importance of optimizing the parameters related to the channel probing phase.

Power Allocation Strategy for Secret Key Generation Method in Wireless Communications

Secret key generation(SKG)is an emerging technology to secure wireless communication from attackers.Therefore,the SKG at the physical layer is an alternate solution over traditional cryptographic methods due to wireless channels’uncertainty.However,the physical layer secret key generation(PHY-SKG)depends on two fundamental parameters,i.e.,coherence time and power allocation.The coherence time for PHY-SKG is not applicable to secure wireless channels.This is because coherence time is for a certain period of time.Thus,legitimate users generate the secret keys(SKs)with a shorter key length in size.Hence,an attacker can quickly get information about the SKs.Consequently,the attacker can easily get valuable information from authentic users.Therefore,we considered the scheme of power allocation to enhance the secret key generation rate(SKGR)between legitimate users.Hence,we propose an alternative method,i.e.,a power allocation,to improve the SKGR.Our results show 72%higher SKGR in bits/sec by increasing power transmission.In addition,the power transmission is based on two important parameters,i.e.,epsilon and power loss factor,as given in power transmission equations.We found out that a higher value of epsilon impacts power transmission and subsequently impacts the SKGR.The SKGR is approximately 40.7%greater at 250 from 50 mW at epsilon=1.The value of SKGR is reduced to 18.5%at 250 mW when epsilonis 0.5.Furthermore,the transmission power is also measured against the different power loss factor values,i.e.,3.5,3,and 2.5,respectively,at epsilon=0.5.Hence,it is concluded that the value of epsilon and power loss factor impacts power transmission and,consequently,impacts the SKGR.

Pattern-reconfigurable antenna-assisted secret key generation from multipath fading channels

Physical layer key generation(PKG)technology leverages reciprocal channel randomness to generate shared secret keys.However,multipath fading at the receiver may degrade the correlation between legitimate uplink and downlink channels,resulting in a low key generation rate(KGR).In this paper,we propose a PKG scheme based on the pattern-reconfigurable antenna(PRA)to boost the secret key capacity.First,we propose a reconfigurable intelligent surface(RIS)based PRA architecture with the capability of flexible and reconfigurable antenna patterns.Then,we present the PRA-based PKG protocol to improve the KGR via mitigation of the effects of multipath fading.Specifically,a novel algorithm for estimation of the multipath channel parameters is proposed based on atomic norm minimization.Thereafter,a novel optimization method for the matching reception of multipath signals is formulated based on the improved binary particle swarm optimization(BPSO)algorithm.Finally,simulation results show that the proposed scheme can resist multipath fading and achieve a high KGR compared to existing schemes.Moreover,our findings indicate that the increased degree of freedom of the antenna patterns can significantly increase the secret key capacity.

Physical layer secret key generation scheme used in 60 GHz band

The technology of 60 GHz radio is considered promising for providing fast connectivity and gigabit data rate. One of the main challenges to its secure indoor transmission is how to generate secret keys between communication devices. To investigate this issue, The authors develop an efficient mechanism of secret key generation exploiting multipath relative delay based on 60 GHz standard channel models. The comparison of key-mismatch probability between line-of-sight （LOS） and non-line-of-sight （NLOS） environments is considered. Verification of the proposed scheme is conducted. Simulation shows that the number of extracted multipath components proportionally did affect key generation rate and key-mismatch probability. It also indicates that communicating transceivers have a slightly lower key-mismatch probability in NLOS condition than in LOS condition. Moreover, in comparison to the existing approach of using received signal amplitude as a common random source, the mechanism can achieve better performance in key agreement.

Methodologies of Secret-Key Agreement Using Wireless Channel Characteristics

In this article, we give an overview of current research on shared secret-key agreement between two parties. This agreement is based on radio wireless channel characteristics. We discuss the advantages of this approach over traditional cryptographic mechanisms and present the theoretical background of this approach. We then give a detailed description of the key-agreement process and the threat model, and we summarize the typical performance metrics for shared secret-key agreement. There are four processes in shared secret-key agreement： sampling, quantization, information reconciliation, and privacy amplification. We classify prior and current research in this area according to innovation on these four processes. We conclude with a discussion of existing challenges and directions for future work.

Analysis and Application of Endogenous Wireless Security Principle for Key Generation

The open and broadcast nature of wireless channels leads to the inherent security problem of information leakage in wireless communication.We can utilize endogenous security functions to resolve this problem.The fundamental solution is channel-based mechanisms,like physical layer secret keys.Unfortunately,current investigations have not fully exploited the randomness of wireless channels,making secret key rates not high.Consequently,user data can be encrypted by reducing the data rate to match the secret key rate.Based on the analysis of the endogenous wireless security principle,we proposed that the channel-based endogenous secret key rate can nearly match the maximum data rate in the fast-fading environments.After that,we validated the proposition in an instantiation system with multiple phase shift keying(MPSK)inputs from the perspectives of both theoretical analysis and simulation experiments.The results indicate that it is possible to accomplish the onetime pad without decreasing the data rate via channelbased endogenous keys.Besides,we can realize highspeed endogenously secure transmission by introducing independent channels in the domains of frequency,space,or time.The conclusions derived provide a new idea for wireless security and promote the application of the endogenous security theory.

Physical layer authentication for automotive cyber physical systems based on modified HB protocol

Automotive cyber physical systems(CPSs)are ever more utilizing wireless technology for V2X communication as a potential way out for challenges regarding collision detection,wire strap up troubles and collision avoidance.However,security is constrained as a result of the energy and performance limitations of modem wireless systems.Accordingly,the need for efficient secret key generation and management mechanism for secured communication among computationally weak wireless devices has motivated the introduction of new authentication protocols.Recently,there has been a great interest in physical layer based secret key generation schemes by utilizing channel reciprocity.Consequently,it is observed that the sequence generated by two communicating parties contain mismatched bits which need to be reconciled by exchanging information over a public channel.This can be an immense security threat as it may let an adversary attain and recover segments of the key in known channel conditions.We proposed Hopper-Blum based physical layer(HB-PL)authentication scheme in which an enhanced physical layer key generation method integrates the Hopper-Blum(HB)authentication protocol.The information collected from the shared channel is used as secret keys for the HB protocol and the mismatched bits are used as the induced noise for learning parity with noise(LPN)problem.The proposed scheme aims to provide a way out for bit reconciliation process without leakage of information over a public channel.Moreover,HB protocol is computationally efficient and simple which helps to reduce the number of exchange messages during the authentication process.We have performed several experiments which show that our proposed design can generate secret keys with improved security strength and high performance in comparison to the current authentication techniques.Our scheme requires less than 55 exchange messages to achieve more than 95%of correct authentication.