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

International Conference on Communications

Experimental Investigation of MIMO Reciprocal Channel Key Generation

Jon W. Wallace, R. K. Sharma

Published May 1, 2010• 10 citations
Publisher

Abstract

There is growing interest in physical-layer key generation schemes that provide very strong or even perfect security in wireless communication systems. One such scheme is reciprocal channel key generation, where two nodes quantize reciprocal channel state information to generate keys. Although the use of multiple-input multiple-output (MIMO) techniques is interesting in this case since the number of random parameters available for rapid key generation is increased, MIMO techniques may also provide more information to an eavesdropper. This work presents a new MIMO measurement campaign performed in LOS and NLOS indoor environments that studies the correlation of the channel between legitimate users with the eavesdropper channel, revealing what key generation rates can be attained in practice and what fraction of generated key bits are safe from eavesdroppers. The effect of eavesdropper separation, number of antennas, eavesdropper advantage, and covariance separability are studied.

DOI
10.1109/icc.2010.5502078

Related papers

Measured statistics of reciprocal channel key generation of indoor MIMO channels

R. K. Sharma, J W Wallace

There is growing interest in physical-layer security methods that exploit the random nature of the physical propagation channel to strengthen existing crypto-systems. In reciprocal channel key generation (RCKG), legitimate nodes (Alice and Bob) observe a common fluctuating channel to generate keys that are safe from the eavesdropper (Eve). Previous work [1, 2] derived expressions for the available key bits and those safe from an eavesdropper for MIMO systems with correlated complex Gaussian statistics. This paper applies these expressions to new MIMO measurements in indoor LOS and NLOS environments, indicating how propagation effects limit secure key generation and what key generation rates can be expected in practice.

Digest - IEEE Antennas and Propagation Society. International Symposium•Jul 1, 2010•1 citation

Automatic Secret Keys From Reciprocal MIMO Wireless Channels: Measurement and Analysis

Jon W. Wal, R. K. Sharma

Information theoretic limits for random key generation in multiple-input multiple-output (MIMO) wireless systems exhibiting a reciprocal channel response are investigated experimentally with a new three-node MIMO measurement campaign. As background, simple expressions are presented for the number of available key bits, as well as the number of bits that are secure from a close eavesdropper. Two methods for generating secret keys are analyzed in the context of MIMO channels and their mismatch rate and efficiency are derived. A new wideband indoor MIMO measurement campaign in the 2.51- to 2.59-GHz band is presented, whose purpose is to study the number of available key bits in both line-of-sight and nonline-of-sight environments. Application of the key generation methods to measured propagation channels indicates key generation rates that can be obtained in practice for four-element arrays.

IEEE Transactions on Information Forensics and Security•Jun 16, 2010•256 citations

Secret Key Generation With Precoding and Role Reversal in MIMO Wireless Systems

Saygın Bakşi, Dimitrie C. Popescu

Secret key generation based on channel measurements has emerged as a meaningful approach to enhance the security of wireless links. The key generation mechanism takes advantage of wireless channel reciprocity and uses the mutual information between legitimate users' channel measurements. However, the rate at which key bits are generated depends on the channel coherence time. Furthermore, eavesdroppers may obtain information to generate the secret key bits if their channels become correlated to the legitimate channels. In this paper, we propose a new approach for key generation that uses MIMO precoding and role switching by legitimate users during the key generation process in order to prevent an eavesdropper whose channel is correlated with the legitimate channel to acquire information that can be used to generate the encryption key, while also ensuring that the rate at which uncorrelated key bits are generated does not depend on the channel coherence time. The proposed approach is supported by an information theoretic analysis and is illustrated with numerical results obtained from simulations showing that, even when the legitimate and eavesdropper channels are correlated, the bit mismatch rate at the eavesdropper does not improve with increasing SNR, while that at the legitimate users improves.

IEEE Transactions on Wireless Communications•Apr 16, 2019•27 citations

Secure Physical Layer Key Generation Schemes: Performance and Information Theoretic Limits

Jon W. Wallace

There is growing interest in wireless security methods that provide strong or even perfect secrecy by taking advantage of features of the physical propagation channel. In advantage-based methods, high channel quality in an average or opportunistic sense is exploited between two legitimate nodes, such that nonzero secrecy capacity can be achieved. Since such methods require bounds on the quality of the eavesdropper channel, they are somewhat impractical. Secret key generation based on tracking channel evolution in time division duplex systems is a more attractive option, where two nodes generate secret key bits based on a mutually known random channel. Since the eavesdropper channel is typically independent of the legitimate channel, the key can only be broken by brute force attacks, which are difficult when new keys are continuously generated. In this paper, the information theoretic limits of key generation schemes are investigated, based on the level of estimation error, temporal correlation, and dependence of the eavesdropper and legitimate channels. Three practical candidate key generation schemes are also considered: channel quantization and channel quantization with guardband.

International Conference on Communications•Jun 1, 2009•82 citations

Analysis of Secret Key Randomness Exploiting the Radio Channel Variability

Taghrid Mazloum, Alain Sibille

A few years ago, physical layer based techniques have started to be considered as a way to improve security in wireless communications. A well known problem is the management of ciphering keys, both regarding the generation and distribution of these keys. A way to alleviate such difficulties is to use a common source of randomness for the legitimate terminals, not accessible to an eavesdropper. This is the case of the fading propagation channel, when exact or approximate reciprocity applies. Although this principle has been known for long, not so many works have evaluated the effect of radio channel properties in practical environments on the degree of randomness of the generated keys. To this end, we here investigate indoor radio channel measurements in different environments and settings at either 2.4625 GHz or 5.4 GHz band, of particular interest for WIFI related standards. Key bits are extracted by quantizing the complex channel coefficients and their randomness is evaluated using the NIST test suite. We then look at the impact of the carrier frequency, the channel variability in the space, time, and frequency degrees of freedom used to construct a long secret key, in relation to the nature of the radio environment such as the LOS/NLOS character.

International Journal of Antennas and Propagation•Jan 1, 2015•3 citations

Blind channel estimation based robust physical layer key generation in MIMO networks

Ravi P. Ramachandran, Sachin S. Shetty

An emerging area of interest in wireless security is the generation of secret encryption keys by leveraging the features of the physical propagation channel. The shared randomness of the wireless channel between two legitimate nodes in a communication network is exploited to provide strong secrecy. The secret keys are generated based on fluctuations or evolution of the wireless channel state. However, to the best of our knowledge, little work has been performed on algorithms to exploit the increased randomness available to wireless nodes equipped with MIMO antennas. In this paper, we present a practical key generation scheme for MIMO channels based on quantization performed on blind channel estimates. Our schemes generate random keys for transmitter and receiver by simultaneously quantizing the blind channel estimates. Our schemes are simulated for a realistic fading channel model, and performance metrics for error rate and efficiency are provided.

IEEE International Symposium on Circuits and Systems proceedings•May 1, 2010•3 citations
There is growing interest in physical-layer key generation schemes that provide very strong or even perfect security in wireless communication systems. One such scheme is reciprocal channel key generation, where two nodes quantize reciprocal channel state information to generate keys. Although the use of multiple-input multiple-output (MIMO) techniques is interesting in this case since the number of random parameters available for rapid key generation is increased, MIMO techniques may also provide more information to an eavesdropper. This work presents a new MIMO measurement campaign performed in LOS and NLOS indoor environments that studies the correlation of the channel between legitimate users with the eavesdropper channel, revealing what key generation rates can be attained in practice and what fraction of generated key bits are safe from eavesdroppers. The effect of eavesdropper separation, number of antennas, eavesdropper advantage, and covariance separability are studied.
There is growing interest in physical-layer security methods that exploit the random nature of the physical propagation channel to strengthen existing crypto-systems. In reciprocal channel key generation (RCKG), legitimate nodes (Alice and Bob) observe a common fluctuating channel to generate keys that are safe from the eavesdropper (Eve). Previous work [1, 2] derived expressions for the available key bits and those safe from an eavesdropper for MIMO systems with correlated complex Gaussian statistics. This paper applies these expressions to new MIMO measurements in indoor LOS and NLOS environments, indicating how propagation effects limit secure key generation and what key generation rates can be expected in practice.
Information theoretic limits for random key generation in multiple-input multiple-output (MIMO) wireless systems exhibiting a reciprocal channel response are investigated experimentally with a new three-node MIMO measurement campaign. As background, simple expressions are presented for the number of available key bits, as well as the number of bits that are secure from a close eavesdropper. Two methods for generating secret keys are analyzed in the context of MIMO channels and their mismatch rate and efficiency are derived. A new wideband indoor MIMO measurement campaign in the 2.51- to 2.59-GHz band is presented, whose purpose is to study the number of available key bits in both line-of-sight and nonline-of-sight environments. Application of the key generation methods to measured propagation channels indicates key generation rates that can be obtained in practice for four-element arrays.
Secret key generation based on channel measurements has emerged as a meaningful approach to enhance the security of wireless links. The key generation mechanism takes advantage of wireless channel reciprocity and uses the mutual information between legitimate users' channel measurements. However, the rate at which key bits are generated depends on the channel coherence time. Furthermore, eavesdroppers may obtain information to generate the secret key bits if their channels become correlated to the legitimate channels. In this paper, we propose a new approach for key generation that uses MIMO precoding and role switching by legitimate users during the key generation process in order to prevent an eavesdropper whose channel is correlated with the legitimate channel to acquire information that can be used to generate the encryption key, while also ensuring that the rate at which uncorrelated key bits are generated does not depend on the channel coherence time. The proposed approach is supported by an information theoretic analysis and is illustrated with numerical results obtained from simulations showing that, even when the legitimate and eavesdropper channels are correlated, the bit mismatch rate at the eavesdropper does not improve with increasing SNR, while that at the legitimate users improves.
There is growing interest in wireless security methods that provide strong or even perfect secrecy by taking advantage of features of the physical propagation channel. In advantage-based methods, high channel quality in an average or opportunistic sense is exploited between two legitimate nodes, such that nonzero secrecy capacity can be achieved. Since such methods require bounds on the quality of the eavesdropper channel, they are somewhat impractical. Secret key generation based on tracking channel evolution in time division duplex systems is a more attractive option, where two nodes generate secret key bits based on a mutually known random channel. Since the eavesdropper channel is typically independent of the legitimate channel, the key can only be broken by brute force attacks, which are difficult when new keys are continuously generated. In this paper, the information theoretic limits of key generation schemes are investigated, based on the level of estimation error, temporal correlation, and dependence of the eavesdropper and legitimate channels. Three practical candidate key generation schemes are also considered: channel quantization and channel quantization with guardband.
A few years ago, physical layer based techniques have started to be considered as a way to improve security in wireless communications. A well known problem is the management of ciphering keys, both regarding the generation and distribution of these keys. A way to alleviate such difficulties is to use a common source of randomness for the legitimate terminals, not accessible to an eavesdropper. This is the case of the fading propagation channel, when exact or approximate reciprocity applies. Although this principle has been known for long, not so many works have evaluated the effect of radio channel properties in practical environments on the degree of randomness of the generated keys. To this end, we here investigate indoor radio channel measurements in different environments and settings at either 2.4625 GHz or 5.4 GHz band, of particular interest for WIFI related standards. Key bits are extracted by quantizing the complex channel coefficients and their randomness is evaluated using the NIST test suite. We then look at the impact of the carrier frequency, the channel variability in the space, time, and frequency degrees of freedom used to construct a long secret key, in relation to the nature of the radio environment such as the LOS/NLOS character.
An emerging area of interest in wireless security is the generation of secret encryption keys by leveraging the features of the physical propagation channel. The shared randomness of the wireless channel between two legitimate nodes in a communication network is exploited to provide strong secrecy. The secret keys are generated based on fluctuations or evolution of the wireless channel state. However, to the best of our knowledge, little work has been performed on algorithms to exploit the increased randomness available to wireless nodes equipped with MIMO antennas. In this paper, we present a practical key generation scheme for MIMO channels based on quantization performed on blind channel estimates. Our schemes generate random keys for transmitter and receiver by simultaneously quantizing the blind channel estimates. Our schemes are simulated for a realistic fading channel model, and performance metrics for error rate and efficiency are provided.