Skema Secret Key Generation (SKG) untuk Keamanan pada Sistem Komunikasi di Lingkungan Wireless

Skema Secret Key Generation (SKG) yang mengeksploitasi sifat reciprocity dan keacakan kanal wireless untuk membangkitkan secret key telah menjadi area penelitian yang semakin menarik dan menjanjikan. Terdapat 3 permasalahan utama dalam pembangunan skema SKG yang efisien yang harus diatasi, yaitu trade-off antara parameter performansi Key Disagreement Rate (KDR) dan Key Generation Rate (KGR), tingginya kompleksitas implementasi karena banyaknya tahapan yang harus dilalui, serta tidak efisiennya skema SKG yang dibangun sehingga tidak sesuai jika diimplementasikan pada perangkat Internet of Things(IoT) yang memiliki keterbatasan sumber daya. Disertasi ini berkontribusi dalam mengatasi ketiga permasalahan tersebut. Kontribusi pertama yang dilakukan untuk mengatasi trade-off antara parameter performansi KDR dan KGR adalah didapatkannya kombinasi yang optimal antara metode pra proses yaitu Kalman Filter, Modified Polynomial Regression (MPR), serta Savitzky Golay Filter dan kuantisasi multilevel. Hasil yang didapat adalah penurunan KDR dan peningkatan KGR dibandingkan dengan skema yang eksisting. Kontribusi kedua dari disertasi ini adalah mekanisme penyederhanaan skema SKG dengan kombinasi metode Modified Kalman (MK) serta Combined Multilevel Quantization (CMQ) sehingga bisa dihasilkan secret key yang identik tanpa melalui tahap rekonsiliasi informasi. Hasil pengujian yang dilakukan menghasilkan 4 blok 128-bit data di lingkungan tanpa halangan serta 2 blok 128-bit data yang memiliki KDR sebesar 0 sehingga tidak memerlukan koreksi untuk mendapatkan secret key yang identik. Kontribusi ketiga dari disertasi ini adalah didapatkannya skema SKG Signal Strength Exchange (SSE) yang efisien dalam hal waktu komputasi dan overhead komunikasi dengan menggunakan metode Synchronized Quantization (SQ) sebagai bagian dari skema SKG SSE. Hasil yang didapat menunjukkan penurunan waktu komputasi menjadi sebesar 3.8% dan overhead komunikasi menjadi sebesar 34% skema yang eksisting. Kontribusi yang dihasilkan dalam disertasi ini diharapkan dapat menjadi salah satu solusi alternatif pembentukan kunci simetris yang tidak membutuhkan kompleksitas komputasi serta Trusted Third Party (TTP), sehingga cocok jika digunakan pada berbagai aplikasi IoT

Optimal signalling strategies and power allocation for secret key generation schemes in the presence of a jammer

Secret key generation (SKG) schemes have been shown to be vulnerable to denial of service (DoS) attacks in the form of jamming. In this paper, a comprehensive study on the impact of correlated and uncorrelated jamming in wireless SKG systems is presented. First, optimal signalling schemes for the legitimate users and jamming approaches for an active adversary launching a DoS attack on the SKG system are derived. It is shown that the legitimate users should employ constant signalling. On the other hand, the jammer should inject either correlated jamming when imperfect channel state information (CSI) regarding the main channel is at their disposal, or, uncorrelated jamming when the main channel CSI is completely unknown. In both cases, optimal power allocation policies are studied under short-term power constrains for M block fading additive white Gaussian noise (BF-AWGN) channels. Numerical evaluations demonstrate that equidistribution of the jamming power is near-optimal in the case of uncorrelated jamming

Multi-factor Physical Layer Security Authentication in Short Blocklength Communication

Lightweight and low latency security schemes at the physical layer that have recently attracted a lot of attention include: (i) physical unclonable functions (PUFs), (ii) localization based authentication, and, (iii) secret key generation (SKG) from wireless fading coefficients. In this paper, we focus on short blocklengths and propose a fast, privacy preserving, multi-factor authentication protocol that uniquely combines PUFs, proximity estimation and SKG. We focus on delay constrained applications and demonstrate the performance of the SKG scheme in the short blocklength by providing a numerical comparison of three families of channel codes, including half rate low density parity check codes (LDPC), Bose Chaudhuri Hocquenghem (BCH), and, Polar Slepian Wolf codes for n=512, 1024. The SKG keys are incorporated in a zero-round-trip-time resumption protocol for fast re-authentication. All schemes of the proposed mutual authentication protocol are shown to be secure through formal proofs using Burrows, Abadi and Needham (BAN) and Mao and Boyd (MB) logic as well as the Tamarin-prover

Secret Key Generation in Rayleigh Block Fading AWGN Channels under Jamming Attacks

Jamming attacks have been shown to disrupt secret key generation (SKG) in systems that exploit the reciprocity of the wireless medium to generate symmetric keys at two remote locations through public discussion. In this study, the use of frequency hopping/spreading in Rayleigh block fading additive white Gaussian noise (BF-AWGN) channels is investigated as a means to counteract such attacks. The competitive interaction between a pair of legitimate users and a jammer is formulated as a zero-sum game and the corresponding Nash equilibria (NE) are characterized analytically and in closed form. It is found that the jammer's optimal strategy is to spread its power across the entire spectrum. On the contrary, the pair of legitimate users should use frequency spreading only in favorable transmission conditions, and frequency hopping otherwise (e.g., low signal to jamming power ratio). Numerical results show that frequency hopping/spreading in BF-AWGN channels is an effective technique for combating jamming attacks in SKG systems; a modest increase of the system bandwidth can substantially increase the SKG rates

Energy Harvesting in Secret Key Generation Systems under Jamming Attacks

Secret key generation (SKG) from shared randomness at two remote locations has been shown to be vulnerable to denial of service attacks in the form of jamming. Typically, such attacks are alleviated with frequency hopping/spreading techniques that rely on expansion of the system bandwidth. In the present study, energy harvesting (EH) is exploited as a novel counter-jamming approach that alleviates the need for extra bandwidth resources. Assuming the legitimate users have EH capabilities, the idea is that part of the jamming signal can potentially be harvested and converted into useful communication power. In this framework, the competitive interaction between a pair of legitimate users and a jammer is formulated as a zero-sum game. A critical transmission power for the legitimate users is identified which allows to completely characterize the unique NE of the game in closed form. Remarkably, this threshold also provides the option to effectively neutralize the jammer, i.e., prevent the jammer from carrying out the attack altogether. Through numerical evaluations, EH is shown to be a counter-jamming approach that can offer substantial gains in terms of relative SKG rates

Energy Harvesting in Secret Key Generation Systems under Jamming Attacks

Secret key generation (SKG) from shared randomness at two remote locations has been shown to be vulnerable to denial of service attacks in the form of jamming. Typically, such attacks are alleviated with frequency hopping/spreading techniques that rely on expansion of the system bandwidth. In the present study, energy harvesting (EH) is exploited as a novel counter-jamming approach that alleviates the need for extra bandwidth resources. Assuming the legitimate users have EH capabilities, the idea is that part of the jamming signal can potentially be harvested and converted into useful communication power. In this framework, the competitive interaction between a pair of legitimate users and a jammer is formulated as a zero-sum game. A critical transmission power for the legitimate users is identified which allows to completely characterize the unique NE of the game in closed form. Remarkably, this threshold also provides the option to effectively neutralize the jammer, i.e., prevent the jammer from carrying out the attack altogether. Through numerical evaluations, EH is shown to be a counter-jamming approach that can offer substantial gains in terms of relative SKG rates

Performance Improvement of Secret Key Generation Scheme in Wireless Indoor Environment

The Secret Key Generation (SKG) scheme that exploits the reciprocity and uniqueness of wireless channel between two users plays a significant part in a new increasing distributed security system. The scheme performance can be distinguished based on the low value of Key disagreement Rate (KDR), the high value of Key Generation Rate (KGR), as well as the fulfillment of the NIST randomness standard. The previous SKG scheme has a high KDR due to a direct quantization of a measurement result of the Received Signal Strength (RSS). To overcome the above issue, we conduct a pre-processing of measurement result before quantization with the Kalman method. The pre-process is carried out to improve the channel reciprocity between two legitimate users with the objective to reduce the bit mismatch. Through an experiment, we propose a new quantization scheme called a Modified Multi-Bit (MMB) that uses a multi-bit system on every level of quantization. The test results show that the proposed combination of preprocessing and the MMB scheme has a better performance compared to the existing schemes in terms of KDR and KGR. The Secret Key generated by our scheme also fulfills the NIST randomness standard

Joint secure communication and sensing in 6G networks

Joint communication and sensing is expected to be one of the features introduced by the sixth-generation (6G) wireless systems. This will enable a huge variety of new applications, hence, it is important to find suitable approaches to secure the exchanged information. Conventional security mechanisms may not be able to meet the stringent delay, power, and complexity requirements which opens the challenge of finding new lightweight security solutions. A promising approach coming from the physical layer is the secret key generation (SKG) from channel fading. While SKG has been investigated for several decades, practical implementations of its full protocol are still scarce. The aim of this chapter is to evaluate the SKG rates in real-life setups under a set of different scenarios. We consider a typical radar waveform and present a full implementation of the SKG protocol. Each step is evaluated to demonstrate that generating keys from the physical layer can be a viable solution for future networks. However, we show that there is not a single solution that can be generalized for all cases, instead, parameters should be chosen according to the context

Authenticated secret key generation in delay-constrained wireless systems

With the emergence of 5G low-latency applications, such as haptics and V2X, low-complexity and low-latency security mechanisms are needed. Promising lightweight mechanisms include physical unclonable functions (PUF) and secret key generation (SKG) at the physical layer, as considered in this paper. In this framework, we propose (i) a zero round trip time (0-RTT) resumption authentication protocol combining PUF and SKG processes, (ii) a novel authenticated encryption (AE) using SKG, and (iii) pipelining of the AE SKG and the encrypted data transfer in order to reduce latency. Implementing the pipelining at PHY, we investigate a parallel SKG approach for multi-carrier systems, where a subset of the subcarriers are used for SKG and the rest for data transmission. The optimal solution to this PHY resource allocation problem is identified under security, power, and delay constraints, by formulating the subcarrier scheduling as a subset-sum 0−1 knapsack optimization. A heuristic algorithm of linear complexity is proposed and shown to incur negligible loss with respect to the optimal dynamic programming solution. All of the proposed mechanisms have the potential to pave the way for a new breed of latency aware security protocols

Protecting Secret Key Generation Systems Against Jamming: Energy Harvesting and Channel Hopping Approaches

Jamming attacks represent a critical vulnerability for wireless secret key generation (SKG) systems. In this paper, two counter-jamming approaches are investigated for SKG systems: first, the employment of energy harvesting (EH) at the legitimate nodes to turn part of the jamming power into useful communication power, and, second, the use of channel hopping or power spreading in block fading channels to reduce the impact of jamming. In both cases, the adversarial interaction between the pair of legitimate nodes and the jammer is formulated as a two-player zero-sum game and the Nash and Stackelberg equilibria are characterized analytically and in closed form. In particular, in the case of EH receivers, the existence of a critical transmission power for the legitimate nodes allows the full characterization of the game's equilibria and also enables the complete neutralization of the jammer. In the case of channel hopping versus power spreading techniques, it is shown that the jammer's optimal strategy is always power spreading while the legitimate nodes should only use power spreading in the high signal-to-interference ratio (SIR) regime. In the low SIR regime, when avoiding the jammer's interference becomes critical, channel hopping is optimal for the legitimate nodes. Numerical results demonstrate the efficiency of both counter-jamming measures