Genom ett undersökande experiment med elektromagnetisk sidokanalattack mot en knappsats för ett kommersiellt passersystem påvisas att informationsläckage i sidokanaler är ett fortsatt aktuellt problem och hur det gör fysisk åtkomstkontroll sårbart genom avlyssning och kopiering av användaruppgifter. Med enkel radioutrustning kan knapptryckningar registreras och avkodas genom oönskad elektromagnetisk strålning och teoretiskt är det möjligt att genomföra avlyssningen på en längre distans med särskilt utformad antenn och anpassad mottagare. Rapporten diskuterar problematiken med emission security hos konsumentprodukter som i militära sammanhang benämns Tempest eller RÖS (röjande signaler) och kräver kostsamma tester för att detekteras och hanteras. I regelverk för EMC (elektromagnetisk kompatibilitet) behandlas elektriska apparaters och näts utstrålning och påverkan av elektromagnetiska vågor, men inte direkt hur information kan läcka från informationsteknologisk utrustning vilket denna rapport vill problematisera. / Through an exploratory experiment using electromagnetic side-channel attack against a keypad for a commercial entry system it is demonstrated that information leakage through side-channels are an ongoing issue and may make entry systems vulnerable by recording of user data. Using simple radio equipment, keypresses can be recorded and decoded by undesired electromagnetic radiation and theoretically it is possible to carry out the attack on a longer distance with a specially designed antenna and a custom recieiver. The report discusses emission security in consumer products which in military context is termed Tempest or compromising emanations (Swedish: RÖS) and requires expensive tests to be detected and handled. The EMC regulations (electromagnetic compatibility) handles radiation and influence of electromagnetic waves in electronic apparatus and nets, but not directly how information can leak from information technology equipment which this report wants to problematize.

This paper discsusses the question: is website oracles in Tor from timing DNS something we have to worry about? This paper builds apon the findings done by Rasmus Dahlberg and Tobias Pulls in thier paper Website Fingerprinting with Website Oracles. A website oracle is a side channel attack that answers the predicate: has this website been visited before? The website oracle is constructed and test are carried out, with great outcome, resulting in that website oracles from timing DNS is not an attack that puts individuals using Tor at risk, but certanly challanges the idea of an anonymity network when such a lot of data can be derived from DNS. / Den här uppsatsen diskuterar frågan: är ett webbplatsorakel från DNS-tidtagning i Tor en attack att oroa sig för? Uppsatsen bygger på tidigare forskning utförd av Rasmus Dahlberg och Tobias Pulls i rapporten Website Fingerprinting with Website Oracles. Ett webbplatsorakel är en sidokanalsattack som svarar på predikatet: är denna webbsida besökt av en specifik delmängd användare? Tor är ett anonymitetsnätverk för gemene man, en viktig teknik för ett utvecklande samhälle där den enskilde individens rätt över sin egen information på internet är under konstant hot. I uppsatsen förklaras vad ett webbplatsorakel är i detalj, hur webbplatsorakel fungerar i Tor-nätverket och hur detta konstrueras i detalj. Resultat presenteras och en diskussion förs med anknytning till dagens teknik och samhälle i stort. Resultaten tyder inte på någon större risk för enskilda användare av Tor men visar på en riskfylld utveckling av perceptionen av hur Tor uppfattas och hur dess rykte kan skadas om attacker likt den presenterad i uppsatsen kan vidareutvecklas. / <p>Presentation utfördes online p.g.a. coronapandemi.</p>

The cryptographic algorithms are commonly used as a security item today. In some situations, the special device is used to run the cryptographic algorithm, so the data are protected against the attack from the internet. Naturally, the attack can be loaded on the device as well using the side channel attack. The data are under the great danger, because nowadays plenty of power consumption analyses exist. The side channel attack uses knowledge about the cryptographic algoritm and simple or differential analysis. The diploma thesis focuses on the differential power analysis attack for the data published under the DPA contest. This thesis covers different types of analyss and attacks, and describes the new DPACv4.2 implementation. The correlation analysis is presented for the DPACv4.2 and the possible attack is discussed at the conclusion.

Shared microarchitectural state is a target for side-channel attacks that leverage timing measurements to leak information across security domains. These attacks are further enhanced by speculative execution, which transiently distorts the control and data flow of applications, and by untrusted environments, where the attacker may have complete control over the victim program. Under these conditions, microarchitectural attacks can bypass software isolation mechanisms, and hence they threaten the security of virtually any application running in a shared environment. Numerous approaches have been proposed to defend against microarchitectural attacks, but we lack the means to test them and ensure their effectiveness. The users cannot test them manually because the effects of the defences are not visible to software. Testing the defences by attempting attacks is also suboptimal because the attacks are inherently unstable, and a failed attack is not always an indicator of a successful defence. Moreover, some classes of defences can be disabled at runtime. Hence, we need automated tools that would check the effectiveness of defences, both at design time and at runtime. Yet, as it is common in security, the existing solutions lag behind the developments in attacks. In this thesis, we propose three techniques that check the effectiveness of defences against modern microarchitectural attacks. Revizor is an approach to automatically detect microarchitectural information leakage in commercial black-box CPUs. SpecFuzz is a technique for dynamic testing of applications to find instances of speculative vulnerabilities. Varys is an approach to runtime monitoring of system defences against microarchitectural attacks. We show that with these techniques, we can successfully detect microarchitectural vulnerabilities in hardware and flaws in defences against them; find unpatched instances of speculative vulnerabilities in software; and detect attempts to invalidate system defences.

In response to the threat of a future, large-scale, quantum computer, the American National Institute of Standards and Technology (NIST) initiated a competition for designs of quantum-resistant cryptographic primitives. In 2022, the lattice-based Module-Learning With Errors (M-LWE) scheme Kyber emerged as the winner to be standardized. The standardization procedure and development of secure implementations call for thorough evaluation and research. One of the main threats to implementations of cryptographic algorithms today is Side-Channel Analysis (SCA), which is the topic of this thesis. Previous work has presented successful power-based attacks on implementations of lattice cryptography protected by masking and even masking combined with shuffling. Shuffling makes SCA harder as the order of independent instructions is randomized, reducing the correlation between operations and power consumption. This randomization is commonly implemented by shuffling the order of the indexes used to iterate over a loop, using the modern Fisher-Yates algorithm. This work describes a new attack that defeats the shuffling countermeasure by first attacking the generation of the index permutation itself. The attack first recovers the positions of the first and last indexes, 0 and 255, and then rotates the encrypted messages using a ciphertext malleability applicable to many ring-based LWE schemes to shift two bits into the known positions from which they can be recovered. This procedure is repeated to recover full messages in 128 rotations. The attack is tested and evaluated on masked and shuffled implementations of Kyber as well as Saber, another similar finalist of the NIST competition which is based on the Module-Learning With Rounding (M-LWR) problem. Compared to the previous attack on masked and shuffled Saber, which required 61,680 traces, the 4,608 needed for this attack demonstrates a 13-fold improvement. / Som svar på hotet från en framtida, storskalig kvantdator initierade amerikanska National Institute of Standards and Technology (NIST) en tävling för design av kvantsäker kryptografi. Den gitter-baserade Module-Learning With Errors algoritmen Kyber valdes 2022 till vinnare och därmed till att standardiseras. Standardiseringsprocessen och utvecklingen av säkra implementationer manar till utvärderingar och forskning. Ett av de primära hoten mot implementationer av kryptografiska algoritmer är sidokanalsanalys, vilket är fokus i detta arbete. Tidigare attacker har genom effektanalys demonsterat lyckade attacker på implementationer av gitter-baserade algoritmer skyddade genom maskering samt maskering och slumpad ordning av operationer. Slumpad ordning av oberoende operationer gör sidokanalsanalys svårare då korrelationen till effektförbrukningen minskar. Denna slumpordning brukar vanligtiv implementeras genom att slumpmässigt permutera, med den moderna implementationen av Fisher-Yates, de index som används i en kodslinga. I detta arbete presenteras en ny attack som till först extraherar positionen av det första och det sista indexen, 0 och 255, innan de två motsvarande meddelandebitarna extraheras. Bitarna i meddelandet roteras till de kända positionerna med en metod för skiffertextmanipulation som är vanlig bland ring-baserade LWE-designer. Denna process upprepas 128 gånger för att få fram hela meddelandet. Attacken has testats och utvärderats på implementationer, skyddade genom maskering kombinerad med slumpad operationsordning, av både Kyber och en liknande NIST-finalist, Saber. Jämfört med den tidigare attacken på Saber med samma skyddsåtgärder minskar den nya metoden det antal mätningar som krävs från 61,608 till 4,608, vilket motsvarar en 13-falding förbättring.

Side-channel attacks have become a realistic threat to the implementations of cryptographic algorithms. By analyzing the unintentional, side-channel leakage, the attacker is able to recover the secret of the target. Recently, a new type of side-channel leakage has been discovered, called far field EM emissions. Unlike attacks based on near field EM emissions or power consumption, the attack based on far field EM emissions is able to extract the secret key from the victim device of several meters distance. However, existing deep-learning attacks based far field EM commonly use a random or grid search method to optimize neural networks’ hyperparameters. Recently, an automated way for deep learning hyperparameter tuning based on Auto- Keras library, called AutoSCA framework, was applied to near-field EM attacks. In this work, we investigate if AutoSCA could help far field EM side-channel attacks. In our experiments, the target is a Bluetooth-5 supported Nordic Semiconductor nRF52832 development kit implementation of Advanced Encryption Standard (AES). Our experiments show that, by using a deep-learning model generated by the AutoSCA framework, we need 485 traces on average to recover a subkey from traces captured at 15 meters distance from the victim device without repeating each encryption. For the same conditions, the state-of-the-art method uses 510 traces. Furthermore, our model contains only 667,433 trainable parameters in total, implying that it requires roughly 9 times less training resources compared to the larger models in the previous work. / Angrepp på sidokanaler har blivit ett realistiskt hot mot implementeringen av kryptografiska algoritmer.Genom att analysera det oavsiktliga läckaget kan angriparen hitta hemligheten bakom målet.Nyligen har en ny typ av sidokanalläckage upptäckts, kallad fjärrfälts EM-utsläpp.Till skillnad från attacker baserade på nära fält EM- utsläpp eller energiförbrukning, kan attacken baserad på yttre fält EM-utsläpp extrahera den hemliga nyckeln från den skadade anordningen på flera meter avstånd.Men befintliga djupinlärningsattacker baserade på långt fält EM använder ofta en slumpmässig sökmetod för att optimera nervnätens hyperparametrar. Nyligen tillämpades ett automatiserat sätt för djupinlärning av hyperparametern baserad på Auto-Keras- bibliotek, AutoSCA- ramverket, vid EM-angrepp nära fältet.I det här arbetet undersöker vi om AutoSCA kan hjälpa till med EM-angrepp.I våra experiment är målet en Bluetooth-5-stödd nordisk semidirigent nR52832- utvecklingsutrustning för avancerad krypteringsstandard (AES).Våra experiment visar att genom att använda en djupinlärningsmodell skapad av AutoSCA-ramverket, behöver vi 485-spår i genomsnitt för att hämta en subnyckel från spår tagna på 15- meters avstånd från offrets apparat utan att upprepa varje kryptering.Under samma förhållanden använder den senaste metoden 510-spår.Dessutom innehåller vår modell bara 667,433-parametrar som totalt kan användas för utbildning, vilket innebär att det krävs ungefär nio gånger mindre utbildningsresurser jämfört med de större modellerna i det tidigare arbetet.

<p dir="ltr">The proliferation of internet-connected embedded devices in contemporary computing environments has raised significant concerns regarding data security and confidentiality. Most embedded devices rely on computationally secure cryptographic algorithms to address these imperatives. However, despite the mathematical assurances, the physical implementation of these algorithms introduces vulnerabilities. Specifically, side-channel analysis (SCA) attacks exploit information leakage through various channels, including power consumption, electromagnetic (EM) radiation, timing, cache hits and misses, and other observable characteristics. </p><p dir="ltr">Previous research has introduced the concept of attenuating information-sensitive signatures using an analog cascoded current source for power delivery, coupled with an analog biased PMOS-based local negative feedback mechanism to stabilize the internal node. While this approach achieves robust signature suppression, resulting in higher minimum traces to disclosure (MTD) and enhanced security, it remains limited by its analog nature, making it less adaptable across different technology nodes. This thesis proposes a digital-friendly signature suppression technique that employs a digital cascoded current source and leverages a Ring-oscillator-based bleed path. These digital countermeasures can be further enhanced through time-domain obfuscation techniques. Our work demonstrates a state-of-the-art MTD of 1.25 billion traces for an AES-256 implementation. However, these countermeasures lack provable security guarantees, so continuous stress testing is essential for widespread deployment. Different intelligent attacks can be exploited on these physical countermeasures. Notably, this thesis also presents an intelligent attack on signature attenuation-based physical countermeasures and introduces an attack detector. Developing an intelligent attack detector is an integral part of the commercial adoption of physical countermeasures. </p><p dir="ltr">Next, generic physical countermeasures are often deployed in the $V_{DD}$ port as power side channel analysis is carried out through the $V_{DD}$ port. However, any digital circuit has two standard ports, namely $V_{DD}$ and clock port, and countermeasure through the clock port is mainly unexplored except for the system-level clock randomization technique. Even the clock-randomization technique is rendered ineffective in the presence of post-processing techniques. This thesis introduces a side channel resilience technique by introducing a larger slew at the clock, thereby improving MTD by $100\times$.</p><p dir="ltr">Next, these physical countermeasures do not come with any provable security guarantee. Hence, it is important to stress-test the countermeasures. This thesis does so and finds an exploitable point to reduce MTD by 1000$\times$. An attack detector of such an attack is also proposed.</p><p dir="ltr">Further, an attack detection strategy against side-channel analysis (SCA) or fault injection attacks (FIA) is also required. A detection and mitigation approach often gives us the option of duty-cycled countermeasures, hence reducing the energy overhead. This thesis proposes and analyzes a self-aware inductive loop-based attack detection strategy to detect SCA and FIA and enhance the signature attenuation countermeasures. </p><p dir="ltr">Finally, we explore opportunities for integrating these lightweight generic techniques into recently standardized Post-Quantum Cryptographic (PQC) cores. Specifically, we present an optimized implementation of the Saber PQC core, a NIST standardization finalist, achieving the lowest area and energy consumption. Future work could involve deploying lightweight PQC cores with synthesizable physical countermeasures to enhance security against quantum algorithms and physical side-channel attacks.</p>

Esta tese apresenta três novos ataques a equipamentos de pagamento eletrônico que possuem teclado mecânico, conhecidos como \"PIN pads\". Mostramos de três formas distintas como tais equipamentos possuem vulnerabilidades de segurança na camada física que permitem o vazamento do PIN (Personal Identification Number) quando o mesmo é digitado. Demonstramos experimentalmente que é possível inferir com elevada taxa de acerto (100% em um dos ataques) a senha digitada, de forma não-invasiva. Os ataques desenvolvidos são baseados na introdução de sensores nos próprios equipamentos ou em seu ambiente de operação: acelerômetros para análise de vibração, microfones para análise acústica e células de carga para medição de forças do pressionamento. Devido à massificação no uso de sensores por dispositivos de consumo, o roubo de informação por meios não convencionais é atividade crescente. Os resultados dos ataques de baixo custo realizados expõem sérias deficiências no processo de certificação de segurança de tais equipamentos. / This thesis presents three new attacks on electronic payment equipment having mechanical keypads, known as \"PIN pads\". We show in three different ways how they have security vulnerabilities at the physical layer allowing the leak of the PIN (Personal Identification Number) when it is entered. We experimentally demonstrated that it is possible to infer with high success rate (100% in one of the attacks) the password entered on the device, in a non-invasive way. The attacks are based on the placement of sensors inside the equipment itself or in its operating environment: accelerometers for doing vibration analysis, microphones for acoustic analysis and load cells for measuring the pressing force. Due to massive deployment of sensors in consumer devices, information theft by unconventional means is increasing. The results of the low-cost attacks here developed expose serious shortcomings in the process of security certification of such equipment.

Esta tese apresenta três novos ataques a equipamentos de pagamento eletrônico que possuem teclado mecânico, conhecidos como \"PIN pads\". Mostramos de três formas distintas como tais equipamentos possuem vulnerabilidades de segurança na camada física que permitem o vazamento do PIN (Personal Identification Number) quando o mesmo é digitado. Demonstramos experimentalmente que é possível inferir com elevada taxa de acerto (100% em um dos ataques) a senha digitada, de forma não-invasiva. Os ataques desenvolvidos são baseados na introdução de sensores nos próprios equipamentos ou em seu ambiente de operação: acelerômetros para análise de vibração, microfones para análise acústica e células de carga para medição de forças do pressionamento. Devido à massificação no uso de sensores por dispositivos de consumo, o roubo de informação por meios não convencionais é atividade crescente. Os resultados dos ataques de baixo custo realizados expõem sérias deficiências no processo de certificação de segurança de tais equipamentos. / This thesis presents three new attacks on electronic payment equipment having mechanical keypads, known as \"PIN pads\". We show in three different ways how they have security vulnerabilities at the physical layer allowing the leak of the PIN (Personal Identification Number) when it is entered. We experimentally demonstrated that it is possible to infer with high success rate (100% in one of the attacks) the password entered on the device, in a non-invasive way. The attacks are based on the placement of sensors inside the equipment itself or in its operating environment: accelerometers for doing vibration analysis, microphones for acoustic analysis and load cells for measuring the pressing force. Due to massive deployment of sensors in consumer devices, information theft by unconventional means is increasing. The results of the low-cost attacks here developed expose serious shortcomings in the process of security certification of such equipment.

Elliptic curves were first proposed as a basis for public key cryptography in the mid 1980's. They provide public key cryptosystems based on the difficulty of the elliptic curve discrete logarithm problem (ECDLP) , which is so called because of its similarity to the discrete logarithm problem (DLP) over the integers modulo a large prime. One benefit of elliptic curve cryptosystems (ECCs) is that they can use a much shorter key length than other public key cryptosystems to provide an equivalent level of security. For example, 160 bit ECCs are believed to provide about the same level of security as 1024 bit RSA. Also, the level of security provided by an ECC increases faster with key size than for integer based discrete logarithm (dl) or RSA cryptosystems. ECCs can also provide a faster implementation than RSA or dl systems, and use less bandwidth and power. These issues can be crucial in lightweight applications such as smart cards. In the last few years, ECCs have been included or proposed for inclusion in internationally recognized standards. Thus elliptic curve cryptography is set to become an integral part of lightweight applications in the immediate future. This thesis presents an analysis of several important issues for ECCs on lightweight devices. It begins with an introduction to elliptic curves and the algorithms required to implement an ECC. It then gives an analysis of the speed, code size and memory usage of various possible implementation options. Enough details are presented to enable an implementer to choose for implementation those algorithms which give the greatest speed whilst conforming to the code size and ram restrictions of a particular lightweight device. Recommendations are made for new functions to be included on coprocessors for lightweight devices to support ECC implementations Another issue of concern for implementers is the side-channel attacks that have recently been proposed. They obtain information about the cryptosystem by measuring side-channel information such as power consumption and processing time and the information is then used to break implementations that have not incorporated appropriate defences. A new method of defence to protect an implementation from the simple power analysis (spa) method of attack is presented in this thesis. It requires 44% fewer additions and 11% more doublings than the commonly recommended defence of performing a point addition in every loop of the binary scalar multiplication algorithm. The algorithm forms a contribution to the current range of possible spa defences which has a good speed but low memory usage. Another topic of paramount importance to ECCs for lightweight applications is whether the security of fixed curves is equivalent to that of random curves. Because of the inability of lightweight devices to generate secure random curves, fixed curves are used in such devices. These curves provide the additional advantage of requiring less bandwidth, code size and processing time. However, it is intuitively obvious that a large precomputation to aid in the breaking of the elliptic curve discrete logarithm problem (ECDLP) can be made for a fixed curve which would be unavailable for a random curve. Therefore, it would appear that fixed curves are less secure than random curves, but quantifying the loss of security is much more difficult. The thesis performs an examination of fixed curve security taking this observation into account, and includes a definition of equivalent security and an analysis of a variation of Pollard's rho method where computations from solutions of previous ECDLPs can be used to solve subsequent ECDLPs on the same curve. A lower bound on the expected time to solve such ECDLPs using this method is presented, as well as an approximation of the expected time remaining to solve an ECDLP when a given size of precomputation is available. It is concluded that adding a total of 11 bits to the size of a fixed curve provides an equivalent level of security compared to random curves. The final part of the thesis deals with proofs of security of key exchange protocols in the Canetti-Krawczyk proof model. This model has been used since it offers the advantage of a modular proof with reusable components. Firstly a password-based authentication mechanism and its security proof are discussed, followed by an analysis of the use of the authentication mechanism in key exchange protocols. The Canetti-Krawczyk model is then used to examine secure tripartite (three party) key exchange protocols. Tripartite key exchange protocols are particularly suited to ECCs because of the availability of bilinear mappings on elliptic curves, which allow more efficient tripartite key exchange protocols.