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 Antennas and Propagation

Wireless secret key generation exploiting reactance-domain scalar response of multipath fading channels

智之 青野, Kenichi Higuchi, Takashi Ohira, Bokuji Komiyama, Hideichi Sasaoka

Published Nov 1, 2005• 324 citations
Publisher

Abstract

We describe a secure communication scheme that uses the random fluctuation of the natural environment of communication channels. Only the transmitter and the receiver share the communication channel characteristics. From reciprocity between a transmitter and a receiver, it is possible for them to share one-time information of their fluctuating channel. This can provide a secret key agreement scheme without key management and key distribution processes. In this paper, we propose a new secret key generation and agreement scheme that uses the fluctuation of channel characteristics with an electronically steerable parasitic array radiator (ESPAR) antenna. This antenna, which has been proposed and prototyped, is a smart antenna designed for consumers. Using the beam-forming technique of the ESPAR antenna, we can increase the fluctuation of the channel characteristics. From experimental results, we conclude that the proposed scheme has the ability to generate secret keys from the received signal strength indicator (RSSI) profile with sufficient independence.

DOI
10.1109/tap.2005.858853

Related papers

Position Dependence of Key Capacity in Secret Key Agreement Scheme Using ESPAR Antenna

Kawamura Shunichi, Shimizu Takayuki, Hisato Iwai +1 more

As a way to ensure security on wireless communication, a secret key agreement scheme exploiting the unique properties of the wireless medium, the reciprocity of radio propagation and the irregularity of multipath fading, is being proposed [1-3]. The method enables two legitimate users to share a secret key without distributing the actual key, by using the radio propagation channel between the two as a common and exclusive source of randomness upon which a secret key could be derived. As an application of this scheme to environments where the radio propagation characteristics are static, a method employing a variable directivity antenna called the ESPAR antenna [4] has been known to be effective. In this method, secret keys are generated from received signal strength indicator (RSSI) sequences of legitimate users. One known problem of this method is that in environments with simple radio propagation characteristics such as a rectangular room of concrete with no fixtures, the strength of the direct wave becomes the dominant factor affecting the fluctuation of the RSSI, thus increasing the chance for eavesdroppers located near the path of such waves to estimate the secret key. Since all previous considerations of the aforementioned scheme has been done with environments where the legitimate users are in line-of-sight, this paper aims to illustrate how the location of eavesdroppers affect the secrecy of keys generated with the scheme, in a radio propagation environment with no clearly dominant wave. The key capacity in respect to the position of the eavesdropper in such environment is shown using computer simulations.

IEICE Technical Report; IEICE Tech. Rep.•Jun 18, 2009•2 citations

Wireless secret key sharing based on the use of a Variable-Directional Antenna over multipath channels

Коржик Валерий Иванович, Viktor Yakovlev, Guillermo B. Morales-Luna +2 more

It has been proposed recently an approach to generate secret key exploiting reactance-domain scalar response of multipath fading channel. However, the security of the shared key has not been adequately investigated. In this paper we propose a mathematical model of the key distribution protocol based on the use of a Variable-Directional Antenna (VDA) acting on multipath wireless channels. The security of the key distribution protocol (KDP) is estimated in terms of Shannon's information leaking to an eavesdropper. Statistical properties of VDA are investigated by simulation that results in an opportunity to calculate the security of the KDP depending on the mutual locations of the legal user and the eavesdropper. Antenna diversity is considered as a measure to enhance a level of the KDP security.

International Symposium ELMAR (ELMAR)•Jan 1, 2010•0 citations

Secret key generation exploiting antenna beam steering and wave propagation reciprocity

Takashi Ohira

This paper presents a novel physical-layer approach to information security. Unlike conventional mathematical-based encryptors, a secret key is generated from a natural phenomenon, i.e., the multi-path fading of a radio wave. The reciprocity in wave propagation is exploited to share the key with a party on the air. An array of electronically steered parasitic radiators provides time variation in the faded amplitude. This variation exhibits strong spatio-randomness which can never be practically solved by any other party. We show proof-of-concept experiments carried out in an actual indoor environment.

European Microwave Conference (EuMC)•Jan 1, 2005•18 citations

Exploiting Multiple-Antenna Diversity for Shared Secret Key Generation in Wireless Networks

Kai Zeng, Daniel Wu, An Chan +1 more

Generating a secret key between two parties by extracting the shared randomness in the wireless fading channel is an emerging area of research. Previous works focus mainly on single-antenna systems. Multiple-antenna devices have the potential to provide more randomness for key generation than single-antenna ones. However, the performance of key generation using multiple-antenna devices in a real environment remains unknown. Different from the previous theoretical work on multiple-antenna key generation, we propose and implement a shared secret key generation protocol, Multiple-Antenna KEy generator (MAKE) using off-the-shelf 802.11n multiple-antenna devices. We also conduct extensive experiments and analysis in real indoor and outdoor mobile environments. Using the shared randomness extracted from measured Received Signal Strength Indicator (RSSI) to generate keys, our experimental results show that using laptops with three antennas, MAKE can increase the bit generation rate by more than four times over single-antenna systems. Our experiments validate the effectiveness of using multi-level quantization when there is enough mutual information in the channel. Our results also show the trade-off between bit generation rate and bit agreement ratio when using multi-level quantization. We further find that even if an eavesdropper has multiple antennas, she cannot gain much more information about the legitimate channel.

IEEE Conference on Computer Communications (INFOCOM)•Mar 1, 2010•244 citations

Secret key generation exploiting channel characteristics in wireless communications

Kui Ren, Hai Su, Qian Wang

Due to the broadcast nature of wireless channels, wireless communication is vulnerable to eavesdropping, message modification, and node impersonation. Securing the wireless communication requires the shared secret keys between the communicating entities. Traditional security schemes rely on public key infrastructures and cryptographic algorithms to manage secret keys. Recently, many physical-layer-based methods have been proposed as alternative solutions for key generation in wireless networks. These methods exploit the inherent randomness of the wireless fading channel to generate secret keys while providing information-theoretical security without intensive cryptographic computations. This article provides an overview of the existing PHY-based key generation schemes exploiting the randomness of the wireless channels. Specifically, we first introduce the fundamental and general framework of the PHY-based key generation schemes and then categorize them into two classes: received-signal-strength-based and channel- phase-based protocols. Finally, we present a performance comparison of them in terms of key disagreement probability, key generation rate, key bit randomness, scalability, and implementation issues.

IEEE Wireless Communications•Aug 1, 2011•262 citations

A secret key agreement scheme with multi-level quantization and parity check using fluctuation of radio channel property

Shimpei Yasukawa, Hisato Iwai, Hideichi Sasaoka

As a countermeasure for eavesdroppers in wireless communication, a secret key agreement scheme using a variable directional antenna named ESPAR antenna was developed. In this paper, we describe an improved key generation method using multi-level quantization and parity check in the secret key agreement scheme. It enhances key agreement probability in legitimate parties efficiently without reducing the security. There was a trade-off between the key agreement probability and the security. Simulation result shows that the proposed method realizes higher security than the conventional one in the key agreement system using ESPAR antenna.

IEEE International Symposium on Information Theory (ISIT)•Jul 1, 2008•27 citations
We describe a secure communication scheme that uses the random fluctuation of the natural environment of communication channels. Only the transmitter and the receiver share the communication channel characteristics. From reciprocity between a transmitter and a receiver, it is possible for them to share one-time information of their fluctuating channel. This can provide a secret key agreement scheme without key management and key distribution processes. In this paper, we propose a new secret key generation and agreement scheme that uses the fluctuation of channel characteristics with an electronically steerable parasitic array radiator (ESPAR) antenna. This antenna, which has been proposed and prototyped, is a smart antenna designed for consumers. Using the beam-forming technique of the ESPAR antenna, we can increase the fluctuation of the channel characteristics. From experimental results, we conclude that the proposed scheme has the ability to generate secret keys from the received signal strength indicator (RSSI) profile with sufficient independence.
As a way to ensure security on wireless communication, a secret key agreement scheme exploiting the unique properties of the wireless medium, the reciprocity of radio propagation and the irregularity of multipath fading, is being proposed [1-3]. The method enables two legitimate users to share a secret key without distributing the actual key, by using the radio propagation channel between the two as a common and exclusive source of randomness upon which a secret key could be derived. As an application of this scheme to environments where the radio propagation characteristics are static, a method employing a variable directivity antenna called the ESPAR antenna [4] has been known to be effective. In this method, secret keys are generated from received signal strength indicator (RSSI) sequences of legitimate users. One known problem of this method is that in environments with simple radio propagation characteristics such as a rectangular room of concrete with no fixtures, the strength of the direct wave becomes the dominant factor affecting the fluctuation of the RSSI, thus increasing the chance for eavesdroppers located near the path of such waves to estimate the secret key. Since all previous considerations of the aforementioned scheme has been done with environments where the legitimate users are in line-of-sight, this paper aims to illustrate how the location of eavesdroppers affect the secrecy of keys generated with the scheme, in a radio propagation environment with no clearly dominant wave. The key capacity in respect to the position of the eavesdropper in such environment is shown using computer simulations.
It has been proposed recently an approach to generate secret key exploiting reactance-domain scalar response of multipath fading channel. However, the security of the shared key has not been adequately investigated. In this paper we propose a mathematical model of the key distribution protocol based on the use of a Variable-Directional Antenna (VDA) acting on multipath wireless channels. The security of the key distribution protocol (KDP) is estimated in terms of Shannon's information leaking to an eavesdropper. Statistical properties of VDA are investigated by simulation that results in an opportunity to calculate the security of the KDP depending on the mutual locations of the legal user and the eavesdropper. Antenna diversity is considered as a measure to enhance a level of the KDP security.
This paper presents a novel physical-layer approach to information security. Unlike conventional mathematical-based encryptors, a secret key is generated from a natural phenomenon, i.e., the multi-path fading of a radio wave. The reciprocity in wave propagation is exploited to share the key with a party on the air. An array of electronically steered parasitic radiators provides time variation in the faded amplitude. This variation exhibits strong spatio-randomness which can never be practically solved by any other party. We show proof-of-concept experiments carried out in an actual indoor environment.
Generating a secret key between two parties by extracting the shared randomness in the wireless fading channel is an emerging area of research. Previous works focus mainly on single-antenna systems. Multiple-antenna devices have the potential to provide more randomness for key generation than single-antenna ones. However, the performance of key generation using multiple-antenna devices in a real environment remains unknown. Different from the previous theoretical work on multiple-antenna key generation, we propose and implement a shared secret key generation protocol, Multiple-Antenna KEy generator (MAKE) using off-the-shelf 802.11n multiple-antenna devices. We also conduct extensive experiments and analysis in real indoor and outdoor mobile environments. Using the shared randomness extracted from measured Received Signal Strength Indicator (RSSI) to generate keys, our experimental results show that using laptops with three antennas, MAKE can increase the bit generation rate by more than four times over single-antenna systems. Our experiments validate the effectiveness of using multi-level quantization when there is enough mutual information in the channel. Our results also show the trade-off between bit generation rate and bit agreement ratio when using multi-level quantization. We further find that even if an eavesdropper has multiple antennas, she cannot gain much more information about the legitimate channel.
Due to the broadcast nature of wireless channels, wireless communication is vulnerable to eavesdropping, message modification, and node impersonation. Securing the wireless communication requires the shared secret keys between the communicating entities. Traditional security schemes rely on public key infrastructures and cryptographic algorithms to manage secret keys. Recently, many physical-layer-based methods have been proposed as alternative solutions for key generation in wireless networks. These methods exploit the inherent randomness of the wireless fading channel to generate secret keys while providing information-theoretical security without intensive cryptographic computations. This article provides an overview of the existing PHY-based key generation schemes exploiting the randomness of the wireless channels. Specifically, we first introduce the fundamental and general framework of the PHY-based key generation schemes and then categorize them into two classes: received-signal-strength-based and channel- phase-based protocols. Finally, we present a performance comparison of them in terms of key disagreement probability, key generation rate, key bit randomness, scalability, and implementation issues.
As a countermeasure for eavesdroppers in wireless communication, a secret key agreement scheme using a variable directional antenna named ESPAR antenna was developed. In this paper, we describe an improved key generation method using multi-level quantization and parity check in the secret key agreement scheme. It enhances key agreement probability in legitimate parties efficiently without reducing the security. There was a trade-off between the key agreement probability and the security. Simulation result shows that the proposed method realizes higher security than the conventional one in the key agreement system using ESPAR antenna.