Investigation of the efficiency of the Elliptic Curve Cryptosystem for multi-application smart card

Thesis (M.E.Sc.) -- University of Adelaide, Dept. of Engineering, 199

Compromising emissions from a high speed cryptographic embedded system

Specific hardware implementations of cryptographic algorithms have been subject to a number of “side channel” attacks of late. A side channel is any information bearing emission that results from the physical implementation of a cryptographic algorithm. Smartcard realisations have been shown to be particularly vulnerable to these attacks. Other more complex embedded cryptographic systems may also be vulnerable, and each new design needs to be tested. The vulnerability of a recently developed high speed cryptographic accelerator is examined. The purpose of this examination is not only to verify the integrity of the device, but also to allow its designers to make a determination of its level of conformance with any standard that they may wish to comply with. A number of attacks were reviewed initially and two were chosen for examination and implementation - Power Analysis and Electromagnetic Analysis. These particular attacks appeared to offer the greatest threat to this particular system. Experimental techniques were devised to implement these attacks and a simulation and micrcontroller emulation were setup to ensure these techniques were sound. Each experimental setup was successful in attacking the simulated data and the micrcontroller circuit. The significance of this was twofold in that it verified the integrity of the setup and proved that a real threat existed. However, the attacks on the cryptographic accelerator failed in all cases to reveal any significant information. Although this is considered a positive result, it does not prove the integrity of the device as it may be possible for an adversary with more resources to successfully attack the board. It does however increase the level of confidence in this particular product and acts as a stepping stone towards conformance of cryptographic standards. The experimental procedures developed can also be used by designers wishing to test the vulnerability of their own products to these attacks

Privacy-preserving smart nudging system: resistant to traffic analysis and data breach

A solution like Green Transportation Choices with IoT and Smart Nudging (SN) is aiming to resolve urban challenges (e.g., increased traffic, congestion, air pollution, and noise pollution) by influencing people towards environment-friendly decisions in their daily life. The essential aspect of this system is to construct personalized suggestion and positive reinforcement for people to achieve environmentally preferable outcomes. However, the process of tailoring a nudge for a specific person requires a significant amount of personal data (e.g., user's location data, health data, activity and more) analysis. People are willingly giving up their private data for the greater good of society and making SN system a target for adversaries to get people's data and misuse them. Yet, preserving user privacy is subtly discussed and often overlooked in the SN system. Meanwhile, the European union's General data protection regulation (GDPR) tightens European Unions's (EU) already stricter privacy policy. Thus, preserving user privacy is inevitable for a system like SN. Privacy-preserving smart nudging (PPSN) is a new middleware that gives privacy guarantee for both the users and the SN system and additionally offers GDPR compliance. In the PPSN system, users have the full autonomy of their data, and users data is well protected and inaccessible without the participation of the data owner. In addition to that, PPSN system gives protection against adversaries that control all the server but one, observe network traffics and control malicious users. PPSN system's primary insight is to encrypt as much as observable variables if not all and hide the remainder by adding noise. A prototype implementation of the PPSN system achieves a throughput of 105 messages per second with 24 seconds end-to-end latency for 125k users on a quadcore machine and scales linearly with the number of users

Post-Quantum Era Privacy Protection for Intelligent Infrastructures

As we move into a new decade, the global world of Intelligent Infrastructure (II) services integrated into the Internet of Things (IoT) are at the forefront of technological advancements. With billions of connected devices spanning continents through interconnected networks, security and privacy protection techniques for the emerging II services become a paramount concern. In this paper, an up-to-date privacy method mapping and relevant use cases are surveyed for II services. Particularly, we emphasize on post-quantum cryptography techniques that may (or must when quantum computers become a reality) be used in the future through concrete products, pilots, and projects. The topics presented in this paper are of utmost importance as (1) several recent regulations such as Europe's General Data Protection Regulation (GDPR) have given privacy a significant place in digital society, and (2) the increase of IoT/II applications and digital services with growing data collection capabilities are introducing new threats and risks on citizens' privacy. This in-depth survey begins with an overview of security and privacy threats in IoT/IIs. Next, we summarize some selected Privacy-Enhancing Technologies (PETs) suitable for privacy-concerned II services, and then map recent PET schemes based on post-quantum cryptographic primitives which are capable of withstanding quantum computing attacks. This paper also overviews how PETs can be deployed in practical use cases in the scope of IoT/IIs, and maps some current projects, pilots, and products that deal with PETs. A practical case study on the Internet of Vehicles (IoV) is presented to demonstrate how PETs can be applied in reality. Finally, we discuss the main challenges with respect to current PETs and highlight some future directions for developing their post-quantum counterparts

Post-Quantum Elliptic Curve Cryptography

We propose and develop new schemes for post-quantum cryptography based on isogenies over elliptic curves. First we show that ordinary elliptic curves are have less than exponential security against quantum computers. These results were used as the motivation for De Feo, Jao and Pl\^ut's construction of public key cryptosystems using supersingular elliptic curve isogenies. We extend their construction and show that isogenies between supersingular elliptic curves can be used as the underlying hard mathematical problem for other quantum-resistant schemes. For our second contribution, we propose is an undeniable signature scheme based on elliptic curve isogenies. We prove its security under certain reasonable number-theoretic computational assumptions for which no efficient quantum algorithms are known. This proposal represents only the second known quantum-resistant undeniable signature scheme, and the first such scheme secure under a number-theoretic complexity assumption. Finally, we also propose a security model for evaluating the security of authenticated encryption schemes in the post-quantum setting. Our model is based on a combination of the classical Bellare-Namprempre security model for authenticated encryption together with modifications from Boneh and Zhandry to handle message authentication against quantum adversaries. We give a generic construction based on Bellare-Namprempre for producing an authenticated encryption protocol from any quantum-resistant symmetric-key encryption scheme together with any digital signature scheme or MAC admitting any classical security reduction to a quantum-computationally hard problem. We apply the results and show how we can explicitly construct authenticated encryption schemes based on isogenies

Stream ciphers for secure display

In any situation where private, proprietary or highly confidential material is being dealt with, the need to consider aspects of data security has grown ever more important. It is usual to secure such data from its source, over networks and on to the intended recipient. However, data security considerations typically stop at the recipient's processor, leaving connections to a display transmitting raw data which is increasingly in a digital format and of value to an adversary. With a progression to wireless display technologies the prominence of this vulnerability is set to rise, making the implementation of 'secure display' increasingly desirable. Secure display takes aspects of data security right to the display panel itself, potentially minimising the cost, component count and thickness of the final product. Recent developments in display technologies should help make this integration possible. However, the processing of large quantities of time-sensitive data presents a significant challenge in such resource constrained environments. Efficient high- throughput decryption is a crucial aspect of the implementation of secure display and one for which the widely used and well understood block cipher may not be best suited. Stream ciphers present a promising alternative and a number of strong candidate algorithms potentially offer the hardware speed and efficiency required. In the past, similar stream ciphers have suffered from algorithmic vulnerabilities. Although these new-generation designs have done much to respond to this concern, the relatively short 80-bit key lengths of some proposed hardware candidates, when combined with ever-advancing computational power, leads to the thesis identifying exhaustive search of key space as a potential attack vector. To determine the value of protection afforded by such short key lengths a unique hardware key search engine for stream ciphers is developed that makes use of an appropriate data element to improve search efficiency. The simulations from this system indicate that the proposed key lengths may be insufficient for applications where data is of long-term or high value. It is suggested that for the concept of secure display to be accepted, a longer key length should be used

Studies on high-speed hardware implementation of cryptographic algorithms

Cryptographic algorithms are ubiquitous in modern communication systems where they have a central role in ensuring information security. This thesis studies efficient implementation of certain widely-used cryptographic algorithms. Cryptographic algorithms are computationally demanding and software-based implementations are often too slow or power consuming which yields a need for hardware implementation. Field Programmable Gate Arrays (FPGAs) are programmable logic devices which have proven to be highly feasible implementation platforms for cryptographic algorithms because they provide both speed and programmability. Hence, the use of FPGAs for cryptography has been intensively studied in the research community and FPGAs are also the primary implementation platforms in this thesis. This thesis presents techniques allowing faster implementations than existing ones. Such techniques are necessary in order to use high-security cryptographic algorithms in applications requiring high data rates, for example, in heavily loaded network servers. The focus is on Advanced Encryption Standard (AES), the most commonly used secret-key cryptographic algorithm, and Elliptic Curve Cryptography (ECC), public-key cryptographic algorithms which have gained popularity in the recent years and are replacing traditional public-key cryptosystems, such as RSA. Because these algorithms are well-defined and widely-used, the results of this thesis can be directly applied in practice. The contributions of this thesis include improvements to both algorithms and techniques for implementing them. Algorithms are modified in order to make them more suitable for hardware implementation, especially, focusing on increasing parallelism. Several FPGA implementations exploiting these modifications are presented in the thesis including some of the fastest implementations available in the literature. The most important contributions of this thesis relate to ECC and, specifically, to a family of elliptic curves providing faster computations called Koblitz curves. The results of this thesis can, in their part, enable increasing use of cryptographic algorithms in various practical applications where high computation speed is an issue

Sécurité étendue de la cryptographie fondée sur les réseaux euclidiens

Lattice-based cryptography is considered as a quantum-safe alternative for the replacement of currently deployed schemes based on RSA and discrete logarithm on prime fields or elliptic curves. It offers strong theoretical security guarantees, a large array of achievable primitives, and a competitive level of efficiency. Nowadays, in the context of the NIST post-quantum standardization process, future standards may ultimately be chosen and several new lattice-based schemes are high-profile candidates. The cryptographic research has been encouraged to analyze lattice-based cryptosystems, with a particular focus on practical aspects. This thesis is rooted in this effort.In addition to black-box cryptanalysis with classical computing resources, we investigate the extended security of these new lattice-based cryptosystems, employing a broad spectrum of attack models, e.g. quantum, misuse, timing or physical attacks. Accounting that these models have already been applied to a large variety of pre-quantum asymmetric and symmetric schemes before, we concentrate our efforts on leveraging and addressing the new features introduced by lattice structures. Our contribution is twofold: defensive, i.e. countermeasures for implementations of lattice-based schemes and offensive, i.e. cryptanalysis.On the defensive side, in view of the numerous recent timing and physical attacks, we wear our designer’s hat and investigate algorithmic protections. We introduce some new algorithmic and mathematical tools to construct provable algorithmic countermeasures in order to systematically prevent all timing and physical attacks. We thus participate in the actual provable protection of the GLP, BLISS, qTesla and Falcon lattice-based signatures schemes.On the offensive side, we estimate the applicability and complexity of novel attacks leveraging the lack of perfect correctness introduced in certain lattice-based encryption schemes to improve their performance. We show that such a compromise may enable decryption failures attacks in a misuse or quantum model. We finally introduce an algorithmic cryptanalysis tool that assesses the security of the mathematical problem underlying lattice-based schemes when partial knowledge of the secret is available. The usefulness of this new framework is demonstrated with the improvement and automation of several known classical, decryption-failure, and side-channel attacks.La cryptographie fondée sur les réseaux euclidiens représente une alternative prometteuse à la cryptographie asymétrique utilisée actuellement, en raison de sa résistance présumée à un ordinateur quantique universel. Cette nouvelle famille de schémas asymétriques dispose de plusieurs atouts parmi lesquels de fortes garanties théoriques de sécurité, un large choix de primitives et, pour certains de ses représentants, des performances comparables aux standards actuels. Une campagne de standardisation post-quantique organisée par le NIST est en cours et plusieurs schémas utilisant des réseaux euclidiens font partie des favoris. La communauté scientifique a été encouragée à les analyser car ils pourraient à l’avenir être implantés dans tous nos systèmes. L’objectif de cette thèse est de contribuer à cet effort.Nous étudions la sécurité de ces nouveaux cryptosystèmes non seulement au sens de leur résistance à la cryptanalyse en “boîte noire” à l’aide de moyens de calcul classiques, mais aussi selon un spectre plus large de modèles de sécurité, comme les attaques quantiques, les attaques supposant des failles d’utilisation, ou encore les attaques par canaux auxiliaires. Ces différents types d’attaques ont déjà été largement formalisés et étudiés par le passé pour des schémas asymétriques et symétriques pré-quantiques. Dans ce mémoire, nous analysons leur application aux nouvelles structures induites par les réseaux euclidiens. Notre travail est divisé en deux parties complémentaires : les contremesures et les attaques.La première partie regroupe nos contributions à l’effort actuel de conception de nouvelles protections algorithmiques afin de répondre aux nombreuses publications récentes d’attaques par canaux auxiliaires. Les travaux réalisés en équipe auxquels nous avons pris part on abouti à l’introduction de nouveaux outils mathématiques pour construire des contre-mesures algorithmiques, appuyées sur des preuves formelles, qui permettent de prévenir systématiquement les attaques physiques et par analyse de temps d’exécution. Nous avons ainsi participé à la protection de plusieurs schémas de signature fondés sur les réseaux euclidiens comme GLP, BLISS, qTesla ou encore Falcon.Dans une seconde partie consacrée à la cryptanalyse, nous étudions dans un premier temps de nouvelles attaques qui tirent parti du fait que certains schémas de chiffrement à clé publique ou d’établissement de clé peuvent échouer avec une faible probabilité. Ces échecs sont effectivement faiblement corrélés au secret. Notre travail a permis d’exhiber des attaques dites « par échec de déchiffrement » dans des modèles de failles d’utilisation ou des modèles quantiques. Nous avons d’autre part introduit un outil algorithmique de cryptanalyse permettant d’estimer la sécurité du problème mathématique sous-jacent lorsqu’une information partielle sur le secret est donnée. Cet outil s’est avéré utile pour automatiser et améliorer plusieurs attaques connues comme des attaques par échec de déchiffrement, des attaques classiques ou encore des attaques par canaux auxiliaires