Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

IEEE Transactions on Mobile Computing

Threshold Constraints on Symmetric Key Extraction from Rician Fading Estimates

Gill R. Tsouri, David M. Wagner

Published Oct 24, 2012• 18 citations
Publisher

Abstract

Symmetric key establishment using reciprocal quantization of channel estimates in wireless Rician fading environments is considered. The quantization bits from channel-phase and channel-amplitude are treated as the output of a random number generator. We determine threshold constraints on the required minimal distance of the legitimate communicating parties from a passive eavesdropper, and determine threshold constraints on maximal key establishing rates. The analysis makes use of widely accepted statistical test suites applied to the generated bit streams along with a lemma we define and prove. For distance analysis, the minimal required distance from the eavesdropper to maintain perfect secrecy during key establishment is derived. For key establishing rates, the maximal rates are derived while ensuring the generated bits streams pass the statistical test suites. The work results in generic and clear threshold requirements on distance and rates as function of the Rician factor and quantization bit for any transmission frequency. Clear thresholds are useful for systems operating in a-priori known or estimated propagation environments. In addition, we address the effect of imperfect channel reciprocity on key agreement. Results show practical systems can operate under reciprocal and secure conditions, and that channel-phase estimates perform better than channel-amplitude estimates.

DOI
10.1109/tmc.2012.226

Related papers

Analysis of Symmetric Key Establishment Based on Reciprocal Channel Quantization

David M. Wagner

Methods of symmetric key establishment using reciprocal quantization of channel parameters in wireless Rayleigh and Rician fading channels are considered. Two important aspects are addressed through generic analysis: impact of a proximity attack by a passive eavesdropper and achievable key establishing rates. The analysis makes use of the National Institute of Standards and Technology statistical test suite applied to the channel quantization bits as the outputs of a random number generator. For proximity attacks, a passive mobile eavesdropper with an ability to approach one of the communicating parties and a possible signal-to-noise ratio advantage is assumed. The minimal required distance from the eavesdropper in order to maintain perfect secrecy during key establishment is evaluated as a function of the Rician factor and quantization depth. For key establishing rates, the maximal rates are evaluated while ensuring that the generated secret key bits pass the entire statistical test suite. The generic analysis is applied to channel-phase quantization and performance in practical systems is considered as well.

•Jan 1, 2010•1 citation

A practical wireless reciprocity-aware key establishment protocol

Satya Prakash Ponnaluri, Babak Azimi-Sadjadi, Yik‐Kiong Hue +3 more

Practical generation of secret bits using wireless channel measurements between two terminals is presented in this paper. The model used for this implementation assumes imperfect reciprocity between the channel measurements made by the two terminals in the presence of a passive eavesdropper. The channel measurements (e.g., received signal strength values) are used to estimate the secret key rate in order to establish the number of secret bits that can be generated between any two terminals. The main contributions of this paper are: 1) algorithm to generate uncorrelated channel measurements even when channel measurement statistics between the two terminals are time-varying; 2) development of a reconciliation algorithm based on BCH codes, where the statistics of error between bits generated by the two terminals is not known a priori; and 3) implementation of secret bit generation using channel reciprocity in a Linux environment. The channel measurement data that was collected for this paper is available at http://downloads.i-a-i.com/RAPOR.

IEEE Military Communications Conference (MILCOM)•Nov 1, 2016•3 citations

Maximizing the Secret Key Rate for Informed Radios under Different Channel Conditions

Britton T. Quist, Michael A. Jensen

The performance of techniques for establishing secret encryption keys from the reciprocal electromagnetic propagation between two wireless radios is generally measured by comparing the number of key bits generated to the key rate, or the information theoretic bound on the number of key bits that can be determined for a single independent channel estimate. While typically this bound is computed by assuming that the radios have no information regarding the channel, recent work has demonstrated an approach for computing this bound for nodes using beamformed antenna arrays that know the spatial covariance of a wide-sense stationary channel. Since this bound does not directly indicate how to perform practical channel estimation to obtain estimates that can achieve the bound, the prior work demonstrates an approximation that indicates a practical channel estimation procedure while yielding a mutual information near that of the key rate in rich multipath fading environments. This paper demonstrates appreciable degradation in the mutual information achieved using this approximation when the channel includes a line-of-sight component and proposes a modified approximation technique that performs well over a broad range of propagation conditions.

IEEE Transactions on Wireless Communications•Sep 9, 2013•12 citations

An Efficient Security Method Based on Exploiting Channel State Information (CSI)

Jehad M. Hamamreh, Haji Muhammad Furqan, Zain Ali +1 more

A channel amplitude quantization method that can effectively quantize the channel response using just one single threshold value is proposed in order to extract a random manipulating sequence with good secrecy properties. Specifically, a Time Division Duplex (TDD) wireless system is considered over independent identical distributed (i.i.d.) Rayleigh fast fading channel, where potential passive eavesdroppers (Eves) can only estimate their own channel and have no knowledge about CSI between legitimate communication parties. The transmitter (Alice) is only aware of the CSI of the legitimate user (Bob). Particularly, the proposed security technique takes the bits of the transmitted data packets and manipulate them with a logical vector that characterizes the channel randomness based on the estimated CSI gain. The process of manipulation is implemented on a bit level basis using an XOR operation exactly before modulation process. The same XOR operation is implemented after demodulation process on the detected bits to extract the concealed bits. The obtained simulation results show that the employment of such mechanism can ensure data confidentiality. Furthermore, the simulation results are extended to include the effect of the selected quantization threshold on the BER performance of Eve as well as the amount of information leakage to its side. It is shown that security gap region between Bob and Eve is made very large over all expected Signal to Noise ratio (SNR) values despite the small degradation in the bit error rate (BER) performance of Bob because of the expected channel estimation errors due to noise.

International Conference on Frontiers of Information Technology (FIT)•Dec 1, 2017•3 citations

Cooperative Key Establishment Protocol for Full-Duplex Relay Systems

Ali M. Allam

Using the fading channel characteristics, as a randomness source, for the secret key generation earns significant attention because of it’s computational less power and low energy consumption. Current researches focus on point-to-point reciprocal-based key extraction from these randomness sources. Most practical communication situations are non-line of sight, so endpoints use a relaying channel to improve communication performance. Besides that, in the upcoming 5G systems, the full-duplex (FD) communications will be one of the main techniques, which will remove the advantage of using the reciprocal feature in the randomness source common observation. In this paper, we consider the challenge of generating a symmetric secret key between two legitimate parties in the relaying channel with FD capability. We suggest an efficient key extraction protocol that accomplished an acceptable shared secret key rate compared to the direct channel traditional approach. Unlike similar schemes, we provide full statistical analysis for the construction of randomness source from the relaying channel with FD capability. Additionally, we investigate the performance analysis of the suggested key agreement protocol. We also analyze the effect of the curious-but-honest relay and an eavesdropper on the proposed protocol.

International Journal of Communication Networks and Information Security (IJCNIS)•Apr 17, 2022•1 citation

Improper Quantization Decision and Key Entropy Loss in Wireless Physical-Layer Security with False Channel Statistics Knowledge

Apirath Limmanee

Wireless physical-layer security is recently proposed for several types of cutting-edge networks, such as 5G and 6G. In wireless physical-layer security, it is usually suggested in literature that eavesdroppers need to locate themselves near legitimate transmitters or receivers if they want to steal some secret key information. By means of scenario analysis, this paper shows that if the eavesdropper knows the channel statistics better than the legitimate stations, e.g., know the K-factor estimates of Rician fading channel, they can exploit these knowledges to derive some secret key information. We define a concept called “improper quantization decision loss$k$” as the entropy loss in the generated key that can be obtained by the eavesdropper. We show step-by-step how the eavesdropper can obtain such information. We also propose mathematical expressions of$n$and derive some results based on empirical values of channel parameters available in literature. From our analytical result for an urban area case, the loss is as large as almost 4/5 of key information, thus requiring a privacy amplification process that yields about 1/5 of the original key length. With our new concept, the new upper and lower bounds of vulnerable key bits are derived.

IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)•Sep 12, 2022•2 citations
Symmetric key establishment using reciprocal quantization of channel estimates in wireless Rician fading environments is considered. The quantization bits from channel-phase and channel-amplitude are treated as the output of a random number generator. We determine threshold constraints on the required minimal distance of the legitimate communicating parties from a passive eavesdropper, and determine threshold constraints on maximal key establishing rates. The analysis makes use of widely accepted statistical test suites applied to the generated bit streams along with a lemma we define and prove. For distance analysis, the minimal required distance from the eavesdropper to maintain perfect secrecy during key establishment is derived. For key establishing rates, the maximal rates are derived while ensuring the generated bits streams pass the statistical test suites. The work results in generic and clear threshold requirements on distance and rates as function of the Rician factor and quantization bit for any transmission frequency. Clear thresholds are useful for systems operating in a-priori known or estimated propagation environments. In addition, we address the effect of imperfect channel reciprocity on key agreement. Results show practical systems can operate under reciprocal and secure conditions, and that channel-phase estimates perform better than channel-amplitude estimates.
Methods of symmetric key establishment using reciprocal quantization of channel parameters in wireless Rayleigh and Rician fading channels are considered. Two important aspects are addressed through generic analysis: impact of a proximity attack by a passive eavesdropper and achievable key establishing rates. The analysis makes use of the National Institute of Standards and Technology statistical test suite applied to the channel quantization bits as the outputs of a random number generator. For proximity attacks, a passive mobile eavesdropper with an ability to approach one of the communicating parties and a possible signal-to-noise ratio advantage is assumed. The minimal required distance from the eavesdropper in order to maintain perfect secrecy during key establishment is evaluated as a function of the Rician factor and quantization depth. For key establishing rates, the maximal rates are evaluated while ensuring that the generated secret key bits pass the entire statistical test suite. The generic analysis is applied to channel-phase quantization and performance in practical systems is considered as well.
Practical generation of secret bits using wireless channel measurements between two terminals is presented in this paper. The model used for this implementation assumes imperfect reciprocity between the channel measurements made by the two terminals in the presence of a passive eavesdropper. The channel measurements (e.g., received signal strength values) are used to estimate the secret key rate in order to establish the number of secret bits that can be generated between any two terminals. The main contributions of this paper are: 1) algorithm to generate uncorrelated channel measurements even when channel measurement statistics between the two terminals are time-varying; 2) development of a reconciliation algorithm based on BCH codes, where the statistics of error between bits generated by the two terminals is not known a priori; and 3) implementation of secret bit generation using channel reciprocity in a Linux environment. The channel measurement data that was collected for this paper is available at http://downloads.i-a-i.com/RAPOR.
The performance of techniques for establishing secret encryption keys from the reciprocal electromagnetic propagation between two wireless radios is generally measured by comparing the number of key bits generated to the key rate, or the information theoretic bound on the number of key bits that can be determined for a single independent channel estimate. While typically this bound is computed by assuming that the radios have no information regarding the channel, recent work has demonstrated an approach for computing this bound for nodes using beamformed antenna arrays that know the spatial covariance of a wide-sense stationary channel. Since this bound does not directly indicate how to perform practical channel estimation to obtain estimates that can achieve the bound, the prior work demonstrates an approximation that indicates a practical channel estimation procedure while yielding a mutual information near that of the key rate in rich multipath fading environments. This paper demonstrates appreciable degradation in the mutual information achieved using this approximation when the channel includes a line-of-sight component and proposes a modified approximation technique that performs well over a broad range of propagation conditions.
A channel amplitude quantization method that can effectively quantize the channel response using just one single threshold value is proposed in order to extract a random manipulating sequence with good secrecy properties. Specifically, a Time Division Duplex (TDD) wireless system is considered over independent identical distributed (i.i.d.) Rayleigh fast fading channel, where potential passive eavesdroppers (Eves) can only estimate their own channel and have no knowledge about CSI between legitimate communication parties. The transmitter (Alice) is only aware of the CSI of the legitimate user (Bob). Particularly, the proposed security technique takes the bits of the transmitted data packets and manipulate them with a logical vector that characterizes the channel randomness based on the estimated CSI gain. The process of manipulation is implemented on a bit level basis using an XOR operation exactly before modulation process. The same XOR operation is implemented after demodulation process on the detected bits to extract the concealed bits. The obtained simulation results show that the employment of such mechanism can ensure data confidentiality. Furthermore, the simulation results are extended to include the effect of the selected quantization threshold on the BER performance of Eve as well as the amount of information leakage to its side. It is shown that security gap region between Bob and Eve is made very large over all expected Signal to Noise ratio (SNR) values despite the small degradation in the bit error rate (BER) performance of Bob because of the expected channel estimation errors due to noise.
Using the fading channel characteristics, as a randomness source, for the secret key generation earns significant attention because of it’s computational less power and low energy consumption. Current researches focus on point-to-point reciprocal-based key extraction from these randomness sources. Most practical communication situations are non-line of sight, so endpoints use a relaying channel to improve communication performance. Besides that, in the upcoming 5G systems, the full-duplex (FD) communications will be one of the main techniques, which will remove the advantage of using the reciprocal feature in the randomness source common observation. In this paper, we consider the challenge of generating a symmetric secret key between two legitimate parties in the relaying channel with FD capability. We suggest an efficient key extraction protocol that accomplished an acceptable shared secret key rate compared to the direct channel traditional approach. Unlike similar schemes, we provide full statistical analysis for the construction of randomness source from the relaying channel with FD capability. Additionally, we investigate the performance analysis of the suggested key agreement protocol. We also analyze the effect of the curious-but-honest relay and an eavesdropper on the proposed protocol.
Wireless physical-layer security is recently proposed for several types of cutting-edge networks, such as 5G and 6G. In wireless physical-layer security, it is usually suggested in literature that eavesdroppers need to locate themselves near legitimate transmitters or receivers if they want to steal some secret key information. By means of scenario analysis, this paper shows that if the eavesdropper knows the channel statistics better than the legitimate stations, e.g., know the K-factor estimates of Rician fading channel, they can exploit these knowledges to derive some secret key information. We define a concept called “improper quantization decision losskkk” as the entropy loss in the generated key that can be obtained by the eavesdropper. We show step-by-step how the eavesdropper can obtain such information. We also propose mathematical expressions ofnnnand derive some results based on empirical values of channel parameters available in literature. From our analytical result for an urban area case, the loss is as large as almost 4/5 of key information, thus requiring a privacy amplification process that yields about 1/5 of the original key length. With our new concept, the new upper and lower bounds of vulnerable key bits are derived.