The recent research on randomness of wireless channels shows that the channel state information (CSI) can be harnessed to generate secret keys for wireless communications. This CSI-based key generation claims to be secure due to the spatial independence between the legitimate channel and the eavesdropping channel. However, this paper presents the discovery that the side-channel information about the security key may leak from the electronic instruments when they are measuring the CSI, when the instruments are encrypting/decrypting for key confirmation, or even when the device is communicating with the established key. Through analyzing the side-channel information, the secret keys can be extracted. The side-channel information could be obtained without approaching the legitimate transceiver, thus posing a serious threat to the CSI-based key generation.
The recent research on randomness of wireless channels shows that the channel state information (CSI) can be harnessed to generate secret keys for wireless communications. This CSI-based key generation claims to be secure due to the spatial independence between the legitimate channel and the eavesdropping channel. However, this paper presents the discovery that the side-channel information about the security key may leak from the electronic instruments when they are measuring the CSI, when the instruments are encrypting/decrypting for key confirmation, or even when the device is communicating with the established key. Through analyzing the side-channel information, the secret keys can be extracted. The side-channel information could be obtained without approaching the legitimate transceiver, thus posing a serious threat to the CSI-based key generation.
Numerous research efforts have been made recently on exploiting the randomness of wireless channels to generate secret keys. This channel state information (CSI) based key generation method relies on spatial independence between the legitimate and eavesdropping channels. In this paper, we propose a methodology to extract secret keys through side-channel information. Our methodology involves the capture of side-channel information leaked by the electronic instruments, either when measuring channel characteristics or during encryption/decryption for key confirmation. Secret keys are extracted via analysis of the side-channel information. We provide experiment results to demonstrate the feasibility of our proposed side-channel attack methodology.
The location-specific channel state information can be exploited to generate secret keys for wireless system services, In the multipath wireless environment. Its secrecy capacity was usually studied with the wiretap channel model. This paper proposes a side channel model which is even more threatening to the security of the physical layer randomness based secret keys. We present the information-theoretic analysis of the side channel model, and compare it with the wire-tap model. The analysis indicates that the secret key capacity of the side-channel will be lower than that of the wire-tap channel, especially with a fading scenario. We conduct MATLAB simulation of physical layer randomness based key generation and SPICE simulation of key extraction to observe the side channel leakage of the circuit. The simulation results confirm the consistency of the key bits, thus verifying the feasibility of our proposed side-channel attack scheme against the physical layer security.
Generating keys and keeping them secret is critical in secure communications. Due to the "open-air" nature, key distribution is more susceptible to attacks in wireless communications. An ingenious solution is to generate common secret keys by two communicating parties separately without the need of key exchange or distribution, and regenerate them on needs. Recently, it is promising to extract keys by measuring the random variation in wireless channels, e.g., RSS. In this paper, we propose an efficient Secret Key Extraction protocol without Chasing down Errors, SKECE. It establishes common cryptographic keys for two communicating parties in wireless networks via the realtime measurement of Channel State Information (CSI). It outperforms RSS-based approaches for key generation in terms of multiple subcarriers measurement, perfect symmetry in channel, rapid decorrelation with distance, and high sensitivity towards environments. In the SKECE design, we also propose effective mechanisms such as the adaptive key stream generation, leakage resilient consistence validation, and weighted key recombination, to fully exploit the excellent properties of CSI. We implement SKECE on off-the-shelf 802.11n devices and evaluate its performance via extensive experiments. The results demonstrate that SKECE achieves a more than 3x throughput gain in the key generation from one subcarrier in static scenarios, and due to its high efficiency, a 50% reduction on the communication overhead compared to the state-of-the-art RSS based approaches.
Device-to-device communication is increasingly important for emerging wireless applications, including the Internet of Things and industry mobile networks. To establish a secure communication channel between multiple legitimate devices, key agreement is an essential first step. Physical layer channel information is a promising technology for achieving communication security by generating a shared channel key. In this paper, we propose an efficient and random method for generating channel keys based on channel state information (CSI). Firstly, we preprocess the available subcarriers to reduce the correlation of adjacent subcarriers. Secondly, we propose a novel quantization process to generate random and secure channel keys. The part consists of two phases: the quantization phase and the inconsistency removal phase. In the quantization stage, CSI sub carriers are grouped into small blocks, and appropriate thresholds are generated. Then, wireless users quantize the CSI subcarriers into initial bit streams of 0 and 1 with different thresholds. In the inconsistency removal phase, we design an error correction mechanism where wireless users exchange the discarded index sequences in the initial bit streams to achieve key sequence consistency. We implement the proposed scheme using off-the-shelf wireless devices and evaluate its performance. The experimental results show that each CSI packet can produce 30 bits, which have passed the NIST randomness tests.
With enhancement in wireless technology, security has become an important part in designing of network. Network security is an important aspect of system administration. We are living in a world where there is access to information anywhere, anytime, be it voice, multimedia or data analytics. This information should be provided to the user with the highest possible security. Thus the information exchanged for communication should be highly secured, authentic and only accessible to the authorised user. Recent research has shown that, this security can be provided through RSS (Received Signal Strength) based key generation techniques for authentication of user. But RSS based key generation technique has a drawback that the key generation rate is very low. RSS based technique is highly applicable for mobile devices. In M2M Communication the devices can be static or mobile based. So we explore a technic which is based on Key generation through CSI (Channel State Information) of a channel. Key generation using CSI information can be efficient in the terms of providing security as they can generate quiet a long key as compared to RSS based technique. We deploy an algorithm as a solution to key generation without using additional hardware for key generation and verify that the malicious user is not able to decode the key sighting to the randomness obtained to our algorithm. The major portion of the algorithm concentrates on making the key random so that the attacker is not able to decode the key within a time span which is vulnerable to the communication. When an attacker tries to use the same algorithm and try to sabotage the communication, due to the property of CSI information of OFDM channel, the generated key will be different. Thus it will not match with the secret key used for actual communication. Hence the user will not be able to hijack the communication.
The traditional wireless communication security technology is based on cryptography at the network layer, which exploits computational complexity to make it difficult to crack to achieve encryption. With the ongoing advancement of computing power, computational security may be difficult to maintain. From the viewpoint of information theory, physical layer security technology is an essential instrument for integrating security and communication. This paper mainly studies the quantization steps in the key generation technology of wireless communication physical layer. In this paper, a quantization scheme with extremely low implementation complexity is proposed for key generation. Firstly, utilizing the reciprocity and randomness of the wireless channel, the communication parties conduct channel measurements to collect channel state information (CSI) and study the improvement of CSI extraction by incorporating intelligent reflection surfaces. Then, the proposed hybrid quantization scheme makes full use of CSI and quantizes the CSI and its phase information to obtain key bits. Numerical results show that the proposed scheme improves the quality of key generation and avoids information leakage during transmission, and passes the NIST randomness test.