Advance in Keyless Cryptography

Quantum correlations or entanglement is a basic ingredient for many applications of quantum information theory.One important application using quantum entanglement exploits the correlation nature of entangled photon states is quantum key distribution, which is proven unbreakable in principle and provides the highest possible security that is impossible in classical information theory. However, generating entangled photon pairs is not a simple task -- only approximately one out of a million pump photons decay into a signal and idler photon pair. This low rate of entangled photon pairs is further reduced by the overhead required in order for the rectification of the inevitable errors due to channel imperfections or caused by potential eavesdroppers. As a consequence, quantum key distribution suffers from a low bit rate, which is in the order of hundreds to thousands bits per second or below. On the other hand, the classical public key distribution does not impose a tight limit on the transmission rate. However, it is subject to the risks of eavesdroppers sitting in the middle of the insecure channel. In this paper, we propose a hybrid key distribution method which uses public key distribution method to generate a raw key, and then uses entanglement assisted communication to modify the raw key by inserting a number of quantum bits in the raw key. Building upon the foundation of the unconditional security of quantum key distribution, we use the privacy amplification to make the affection of inserted bits expand to a whole key. Our quantum entanglement assisted key distribution scheme greatly improves the efficiency of key distribution while without compromising the level of security achievable by quantum cryptography.

Wireless Sensor Networks (WSNs) usually contain a large number of wireless sensor devices to monitor and/or control particular parameters. In many applications, the wireless nodes are powered by a small battery which makes the energy consumption a major challenge in designing proper communication protocols and services for WSNs.□One of the key issues in WSNs is key distribution in a safe way. There are many methods for key distribution in the clustering networks. Clustering is one of the promising mechanisms which aims at reducing the energy consumption of the wireless nodes, and thus enlarging the lifetime of the WSN. In this paper, we propose an Efficient Key Distribution Mechanism (EKDM), which is derived from the symmetric polynomial method. Performance analysis reveals that the EKDM against the compromise attack is quite robust, and compared to many other schemes, the cluster heads (CHs) use a more efficient method that reduces the amount of computational overhead, while memory usage is not much more than previous schemes. Moreover, the EKDM fully supports node addition, and key freshness. Consequently, in addition to the high flexibility to determine the appropriate level of security, it requires a small energy consumption. □

Internet of Things (IoT) is becoming an emerging paradigm to provide pervasive connectivity where “anything“ can be connected “anywhere” at “anytime” via massive deployment of physical objects like sensors, controllers, and actuators. However, the open nature of wireless communications and the energy constraint of the IoT devices impose strong security concerns. In this context, traditional cryptographic techniques may not be suitable in such a resource-constrained network. To address this problem, an effective security solution that ensures a trade-off between security effectiveness and energy efficiency is required. In this paper, we exploit cooperative transmission between sensor nodes in IoT for e-Health application, as a promising technique to enhance the physical layer security of wireless communications in terms of secrecy capacity while considering the resource-impoverished devices. Specifically, we propose a dynamic and cooperative virtual multiple-input and multiple-output (MIMO) configuration approach based on game theory to preserve the confidentiality of the transmitted messages with high energy savings. For this purpose, we model the physical layer security cooperation problem as a non-transferable coalition formation game. The set of cooperative devices form a virtual dynamically-configured MIMO network that is able to securely and efficiently transmit data to the destination. Simulation results show that the proposed game-based virtual MIMO configuration approach can improve the average secrecy capacity per device as well as the network lifetime compared to non-cooperative transmission.

The next generation network (5G) promises to offer a wide spectrum of advantages like massive user connections and high mobility. Massive user connection is achieved by incorporating Multiple Input Multiple Output (MIMO). Securing 5G wireless networks is of greater concern because they are developed with the intention of providing exponentially increasing wireless services where a trillion of legitimate users will be involved. Data transmission in 5G networks has been exposed to various security threats such as eavesdropping, jamming, Denial of Service (DoS) attack and Man-In-The-Middle (MITM) attack. The above mentioned threats have the ability of affecting the performance of 5G wireless networks since 5G is a major support system for new use cases. Some of the existing mechanisms employed to deal with the security threats are Physical Layer Security (PLS) and cryptography. PLS is preferred since its primary focus is on physical and Media Access Control (MAC) layer where variations in security between wireless and wired networks occur. The existing PLS approach for security against single cell MIMO eavesdropper is Original Symbol Phase Rotated (OSPR) secure transmission scheme where one base station serves the user terminals in a single cell. Our paper implements OSPR for a multi cell MIMO where multiple base stations serve multiple user terminals located in different cells. This architecture will be referred to as Multi cell MIMO Eavesdropping (MME). The efficiency of multi cell OSPR will be compared with Artificial Noise (AN) generation. The extent to which OSPR gives protection against MIMO eavesdropper is measured in terms of Symbol Error Rate (SER). As SER increases, security of data transmission increases. The efficiency of multi cell OSPR over AN is expected to be 8% and it will be verified in simulation using MATLAB.

SUMMARY In recent wireless communication systems, security is ensured mainly in the upper-layer techniques such as a password or a cryptography processing. However, security needs not be restricted to the upperlayer and the addition of physical-layer security also would yield a much more robust system. Therefore, in this paper, we exploit chaos communication and propose a chaos multiple-input multiple-output (MIMO) transmission scheme which achieves physical-layer security and additional channelcoding gain. A chaotic modulation symbol is multiplied to the data to be transmitted at each MIMO antenna to exploit the MIMO antenna diversity, and at the receiver, the joint MIMO detection and chaos decoding is done by maximum likelihood decoding (MLD). The conventional chaos modulation suffers from bit error rate (BER) performance degradation, while the coding gain is obtained in the proposed scheme by the chaos modulation in MIMO. We evaluate the performances of the proposed scheme by an

Physical layer security is a crucial issue in wireless networks to prevent legitimate communication from eavesdropping. This paper investigates the physical layer security of a wireless multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) communication system in the presence of a multiple-antenna eavesdropper. We first propose a minimum mean square error (MMSE)-based-filter secure MIMO–OFDM system which can destroy the orthogonality of eavesdropper’s signals. The MMSE-based-filter is used at the receiver to suppress the inter-subcarrier interference and disturb the reception of eavesdropper while maintaining the quality of legitimate transmission. Next, we propose another artificial noise (AN)-assisted secure MIMO–OFDM system to further improve the security of the legitimate transmission. The time-domain AN signal is designed to be canceled out at the legitimate receiver. Therefore, AN will disturb the reception of eavesdropper while the legitimate transmission will not be affected. Finally, power allocation for AN signals and subcarriers will be discussed since AN is generated utilizing the residual power of the MIMO–OFDM system. Simulation results are presented to demonstrate the security performance of the proposed transmit filter design and AN-assisted scheme in the MIMO–OFDM system.

The physical layer security (PLS) has become crucial in the fifth generation (5G) wireless technology where non-orthogonal multiple-access (NOMA) plays an essential role for sharing the spectrum among multiple users. Multiple-input multiple-output (MIMO)-NOMA based cognitive radio network (CRN) enhances the spectral-efficiency at the cost of PLS. In this paper, a transmit-zero-forcing beamforming (ZFBF) technique with signal alignment is proposed to improve the PLS for MIMO-NOMA based CRN when perfect channel state information (CSI) is available at the base station (BS). In this study, a generalized cellular model with multi-cell is considered where each cluster is formed with a primary user (PU) and a secondary user (SU) to adopt the CRN. The locations of PU and SU are kept arbitrary within the cells. We also propose an eigen beamforming technique to improve the PLS for MIMO-NOMA based CRN when the imperfect CSI is available at the BS. For both beamforming techniques, optimum power allocation algorithms are developed for further enhancement of the PLS. Finally, a closed-form expression of the secrecy outage probability for the Nakagami-m fading channels is derived and compared with simulation results and other existing techniques.

Key distribution and renewing in wireless local area networks is a crucial issue to guarantee that unauthorized users are prevented from accessing the network. In this paper, we propose a technique for allowing an automatic bootstrap and periodic renewing of the network key by exploiting physical layer security principles, that is, the inherent differences among transmission channels. The proposed technique is based on scrambling of groups of consecutive packets and does not need the use of an initial authentication nor automatic repeat request protocols. We present a modification of the scrambling circuits included in the IEEE 802.11g standard which allows for a suitable error propagation at the unauthorized receiver, thus achieving physical layer security.

: Cryptography provides the means to securely communicate data between authorized entities by using mathematical transformations which utilize preshared cryptographic keys. The need to share key material with authorized entities in a secure, efficient and timely manner has driven efforts to develop new key distribution methods. The most promising method is Quantum Key Distribution (QKD) and is considered to be unconditionally secure because it relies upon the immutable laws of quantum physics rather than computational complexity. Unfortunately, the nonidealities present in actual implementations of QKD systems also result in errors manifested in the quantum data channel. As a consequence, an important component of any QKD system is the error reconciliation protocol which is used to identify and correct inconsistencies in the exchanged key material. This research provides an empirical analysis of the Cascade secret key reconciliation protocol to measure its efficacy under different error rates, sampling rates, error distributions and larger sifted key sizes. The key findings of the research are that 1) an error sampling rate of 25% provides optimal Cascade performance when using variable block sizes, 2) the choice of sifted key length directly impacts the accuracy of Cascade error estimation, 3) the Cascade algorithm performs well in burst error environments with initial permutation, and 4) a tradeoff exists between buffer size and information leaked.

Millimeter-wave (mmWave) wireless communication system allows a compact antenna array with a large number of colocated elements, which enables flexible array design and beampattern synthesis. However, security is also particularly important but challenging for the fifth-generation (5G) wireless communications, as the broadcasting nature allows any receivers to have a copy of the transmitted signals. In this paper, we propose a hybrid multiple-input multiple-output (MIMO) phased-array time-modulated directional modulation (DM) scheme for physical layer security in mmWave wireless communications. The hybrid MIMO phased-array enjoys the advantages of MIMO in spatial diversity without sacrificing the main advantage of phased-array in coherent directional gain. The essence is to divide the transmit array into multiple subarrays. Each subarray can be used to form a directional beam, while all subarrays are jointly combined to work as an MIMO for higher angular resolution capabilities. More importantly, a time-modulated DM scheme is applied for the phased-MIMO to achieve physical layer security for mmWave wireless communications, even without the knowledge of the eavesdropper’s position information. The feasibility of the proposed scheme is verified by numerical results.

Physical-layer security (PLS) has raised the attention of the research community in recent years, particularly for Internet of things (IoT) applications. Despite the use of classical cryptography, PLS provides security at physical layer, regardless of the computational power owned by the attacker. The investigations on PLS are numerous in the literature, but one main issue seems to be kept apart: how to measure the benefit that PLS can bring to cryptography? This paper tries to answer this question with an initial performance analysis of PLS in conjunction with typical cryptography of wireless communication protocols. Our results indicate that PLS can help cryptography to harden the attacker job in real operative scenario: PLS can increase the detection errors at the attacker’s receiver, leading to inability to recover the cipher key, even if the plaintext is known.

The enhanced proliferation of connected entities needs a deployment of innovative technologies for the next generation wireless networks. One of the critical concerns, however, is the spectrum scarcity, due to the unprecedented broadcast penetration rate nowadays. Based on this, visible light communication (VLC) has recently emerged as a viable solution to secure high-speed communications. VLC, a high data rate communication technology, has proven its stature as a promising complementary to its radio frequency (RF) counterpart. VLC is a cost-effective, energy-efficient, and secure technology that exploits the current infrastructure, specifically within indoor and underwater environments. Yet, despite their appealing capabilities, VLC systems face several limitations which constraint their potentials such as LED’s limited bandwidth, dimming, flickering, line-of-sight (LOS) requirement, impact of harsh weather conditions, noise, interference, shadowing, transceiver alignment, signal decoding complexity, and mobility issue. Consequently, non-orthogonal multiple access (NOMA) has been considered an effective technique to circumvent these shortcomings. The NOMA scheme has emerged as a revolutionary paradigm to address the shortcomings of VLC systems. The potentials of NOMA are to increase the number of users, system’s capacity, massive connectivity, and enhance the spectrum and energy efficiency in future communication scenarios. Motivated by this, the presented study offers an overview of NOMA-based VLC systems. This article provides a broad scope of existing research activities of NOMA-based VLC systems. This article aims to provide firsthand knowledge of the prominence of NOMA and VLC and surveys several NOMA-enabled VLC systems. We briefly highlight the potential and capabilities of NOMA-based VLC systems. In addition, we outline the integration of such systems with several emerging technologies such as intelligent reflecting surfaces (IRS), orthogonal frequency division multiplexing (OFDM), multiple-input and multiple-output (MIMO) and unmanned aerial vehicles (UAVs). Furthermore, we focus on NOMA-based hybrid RF/VLC networks and discuss the role of machine learning (ML) tools and physical layer security (PLS) in this domain. In addition, this study also highlights diverse and significant technical hindrances prevailing in NOMA-based VLC systems. We highlight future research directions, along with provided insights that are envisioned to be helpful towards the effective practical deployment of such systems. In a nutshell, this review highlights the existing and ongoing research activities for NOMA-based VLC systems, which will provide sufficient guidelines for research communities working in this domain and it will pave the way for successful deployment of these systems.

Recently, we proposed similar key sharing protocol executed over the public noiseless channels and also without any cryptographic assumptions. Exchange by matrices was believed to have superior performance in that protocol. In the current paper, the matrix exchange was replaced by integer exchange over the same channels. It requires to apply additional subprotocols to make both legitimate and eavesdropper channels worse. A replacing matrices by integers allowed us to derive some probability relations theoretically instead of relying on the simulation results only in our previous paper. Moreover, the use of the integers in place of matrices requires less traffic over channels between legitimate correspondents. The performance evaluation of the proposed protocol in terms of the reliability and security is presented as well.

In this paper, we investigate the secrecy outage performance of the Non-orthogonal Multiple Access system (NOMA) in an untrusted relaying energy harvesting (UEH) network with the multiple-input multiple output (MIMO) architecture using the transmit antenna selection/ maximal ratio combining (MRC) techniques. In proposed network, the source communicates with users under the help of multiple UEH network using the power-splitting (PS). In addition, to improve the secrecy outage performance and protect the confidential source signal from the untrusted relaying network, the source works as the jammer with the role generating the artificial noise (AN). For the evaluation of secrecy performance of each user we derive the closed- form expressions of the secrecy outage probability (SOP) over Rayleigh fading. Moreover, comparisons between MIMO/NOMA and MIMO/OMA systems and the effects of various system parameters are examined. The accuracy of analytical results is verified by Monte Carlo simulations.

Improvements in technology introduce new application for sensor networks. As Mission-critical applications are deployed in distributed wireless sensor networks, security issues arise. They are facing tremendous challenges: wireless communication environment (usually in hostile areas), lack of infrastructure support, inability of predicting network topology and limited resource associated with nodes. Efficient and robust key distribution is important to secure such kind of sensor networks. To address this issue, we propose a simple pair-wise key distribution and management approach. We predistribute an INITIAL_KEY and a PRIVATE_KEY to each sensor. Let each sensor broadcast its encrypted PRIVATE_KEY with limited power. Then every sensor shares a pair-wise key with each of its neighbors. Any pair of adjacent nodes could communicate securely using a common pair-wise key. Node addition and deletion during communication stage are supported, so as to the update of pair-wise keys. Simulation result proves the scalability of our method.