The Internet of Things (IoT) is the next technological leap that will introduce significant improvements to various aspects of the human environment, such as health, commerce, and transport. However, despite the fact that it may bring beneficial economic and social changes, the security and the privacy protection of objects and users remain a crucial challenge that has to be addressed. Specifically, now the security measures have to monitor and control the actions both of users and objects. However, the interconnected and independent nature of objects, as well as their constrained capabilities regarding the computing resources make impossible the applicability of the conventional security mechanisms. Moreover, the heterogeneity of various technologies which the IoT combines increases the complexity of the security processes, since each technology is characterized by different vulnerabilities. Furthermore, the tremendous amounts of data which is generated by the multiple interactions between the users and objects or among the objects make harder their management and the functionality of the access control systems. In this context, this paper intends to provide a comprehensive security analysis of the IoT, by examining and assessing the potential threats and countermeasures. More detailed, after studying and determining the security requirements in the context of the IoT, we implement a qualitative and quantitative risk analysis, investigating the security threats per layer. Subsequently, based on this process we identify the suitable countermeasures and their limitations, paying special attention to the IoT protocols. Finally, we provide research directions for future work.

Securing the Internet of Things: Challenges, threats and solutions

Power side-channel analysis (SCA) has been of immense interest to most embedded designers to evaluate the physical security of the system. This work presents profiling-based cross-device power SCA attacks using deep-learning techniques on 8-bit AVR microcontroller devices running AES-128. First, we show the practical issues that arise in these profiling-based cross-device attacks due to significant device-to-device variations. Second, we show that utilizing principal component analysis (PCA)-based preprocessing and multidevice training, a multilayer perceptron (MLP)-based 256-class classifier can achieve an average accuracy of 99.43% in recovering the first keybyte from all the 30 devices in our data set, even in the presence of significant interdevice variations. Results show that the designed MLP with PCA-based preprocessing outperforms a convolutional neural network (CNN) with four-device training by ~20% in terms of the average test accuracy of cross-device attack for the aligned traces captured using the ChipWhisperer hardware. Finally, to extend the practicality of these cross-device attacks, another preprocessing step, namely, dynamic time warping (DTW) has been utilized to remove any misalignment among the traces, before performing PCA. DTW along with PCA followed by the 256-class MLP classifier provides ≥10.97% higher accuracy than the CNN-based approach for cross-device attack even in the presence of up to 50 time-sample misalignments between the traces.

Practical Approaches Toward Deep-Learning-Based Cross-Device Power Side-Channel Attack

QcBits is a code-based public key algorithm based on a problem thought to be resistant to quantum computer attacks. It is a constant-time implementation for a quasi-cyclic moderate density parity check (QC-MDPC) Niederreiter encryption scheme, and has excellent performance and small key sizes. In this paper, we present a key recovery attack against QcBits. We first used differential power analysis (DPA) against the syndrome computation of the decoding algorithm to recover partial information about one half of the private key. We then used the recovered information to set up a system of noisy binary linear equations. Solving this system of equations gave us the entire key. Finally, we propose a simple but effective countermeasure against the power analysis used during the syndrome calculation.

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A Side-Channel Assisted Cryptanalytic Attack Against QcBits

Over the past decades, quantum technology has seen consistent progress, with notable recent developments in the field of quantum computers. Traditionally, this trend has been primarily seen as a serious risk for cryptography; however, a positive aspect of quantum technology should also be stressed. In this regard, viewing this technology as a resource for honest parties rather than adversaries, it may enhance not only the security, but also the performance of specific cryptographic schemes. While considerable effort has been devoted to the design of quantum-resistant and quantum-enhanced schemes, little effort has been made to understanding their physical security. Physical security deals with the design and implementation of security measures fulfilling the practical requirements of cryptographic primitives, which are equally essential for classic and quantum ones. This survey aims to draw greater attention to the importance of physical security, with a focus on secure key generation and storage as well as secure execution. More specifically, the possibility of performing side-channel analysis in the quantum world is discussed and compared to attacks launched in the classic world. Besides, proposals for quantum random number generation and quantum physically unclonable functions are compared to their classic counterparts and further analyzed to give a better understanding of their features, advantages, and shortcomings. Finally, seen from these three perspectives, this survey provides an outlook for future research in this direction.

Physical Security in the Post-quantum Era: A Survey on Side-channel Analysis, Random Number Generators, and Physically Unclonable Functions

Nowadays public-key cryptography is based on number theory problems, such as computing the discrete logarithm on an elliptic curve or factoring big integers. Even though these problems are considered difficult to solve with the help of a classical computer, they can be solved in polynomial time on a quantum computer. Which is why the research community proposed alternative solutions that are quantum-resistant. The process of finding adequate post-quantum cryptographic schemes has moved to the next level, right after NIST's announcement for post-quantum standardization. One of the oldest quantum-resistant proposition goes back to McEliece in 1978, who proposed a public-key cryptosystem based on coding theory. It benefits of really efficient algorithms as well as a strong mathematical background. Nonetheless, its security has been challenged many times and several variants were cryptanalyzed. However, some versions remain unbroken. In this paper, we propose to give some background on coding theory in order to present some of the main flawless in the protocols. We analyze the existing side-channel attacks and give some recommendations on how to securely implement the most suitable variants. We also detail some structural attacks and potential drawbacks for new variants.

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Survey on cryptanalysis of code-based cryptography: From theoretical to physical attacks

The segment of post-quantum cryptography rises its importance with increasing improvements in the quantum computing. Cryptographic post-quantum algorithms have been proposed since 1970s. However, side-channel attack vulnerabilities of these algorithms are still in focus of the recent research. In this paper, we present a differential power analysis attack on the McEliece public-key cryptosystem. We demonstrate that a part of a private key, permutation matrix, can be recovered using the power analysis. We attack a software implementation of a secure bit permutation that was proposed by Strenzke et al. at PQCrypto 2008. The cryptosystem is implemented on a 32-bit ARM based microcontroller. We provide details of the attack and results using power consumption measurements of the device. In addition, we outline a novel countermeasure against the introduced attack. The countermeasure uses properties of the linear codes and does not require large amount of random bits which can be profitable for low-cost embedded devices.

/pdf/differential-power-analysis-attack-on-the-secure-bit-31g0899z85.pdf

Differential power analysis attack on the secure bit permutation in the McEliece cryptosystem

In this paper, we present a novel countermeasure against a simple power analysis based side channel attack on a software implementation of the McEliece public key cryptosystem. First, we attack a straightforward C implementation of the Goppa codes based McEliece decryption running on an ARM Cortex-M3 microprocessor. Next, we demonstrate on a realistic example that using a “chosen ciphertext attack” method, it is possible to recover the complete secret permutation matrix. We show that this matrix can be completely recovered by an analysis of a dynamic power consumption of the microprocessor. Then, we estimate the brute-force attack complexity reduction depending on the knowledge of the permutation matrix. Finally, we propose an efficient software countermeasure having low computational complexity. Of course, we provide all the necessary details regarding the attack implementation and all the consequences of the proposed countermeasure especially in terms of power consumption.

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Countermeasure against the SPA attack on an embedded McEliece cryptosystem

In this paper, we detail two side-channel attacks against the McEliece public-key cryptosystem. They are exploiting timing differences on the Patterson decoding algorithm in order to reveal one part of the secret key: the support permutation. The first one is improving two existing timing attacks and uses the correlation between two different steps of the decoding algorithm. This improvement can be deployed on all error-vectors with Hamming weight smaller than a quarter of the minimum distance of the code. The second attack targets the evaluation of the error locator polynomial and succeeds on several different decoding algorithms. We also give an appropriate countermeasure.

/pdf/improved-timing-attacks-against-the-secret-permutation-in-1996rsbioj.pdf

Improved Timing Attacks against the Secret Permutation in the McEliece PKC

In this article we discus a probability problem applied in the code based cryptography. It is related to the shape of the polynomials with exactly t different roots. We will show that the structure is very dense and the probability that this type of polynomials has at least one coefficient equal to zero is extremelly low. We treated this issue in our research of natural countermeasures to a timing attack against the polynomial evaluation.

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Tania Richmond

Papers

Survey on cryptanalysis of code-based cryptography: From theoretical to physical attacks

Differential power analysis attack on the secure bit permutation in the McEliece cryptosystem

Countermeasure against the SPA attack on an embedded McEliece cryptosystem

Improved Timing Attacks against the Secret Permutation in the McEliece PKC

Polynomial Structures in Code-Based Cryptography