No description available.

No description available.

The ISAS/JAXA Solar Power Sail mission, bound to explore the Jupiter trojans, will face many challenges during its journey. The landing manoeuvre is one of the most critical parts of any space mission that plans to investigate the surface of celestial bodies. Asteroids are mostly unknown bodies and in order to plan a successful landing on their surface, a great number of landing scenarios need to be taken into account. For the future mission to the Jupiter trojans, a study of the landing dynamics and their effects on the lander has to be done. A simple model of a lander has been created based on a design for the ISAS/JAXA Solar Power Sail mission, and the possible landing scenarios have been simulated. For this case, only the last part of the landing, which will be a free-fall has been taken into account. The lander is modelled as a rigid structure with a landing gear composed of four legs. The surface has been modelled as a flat plane with different inclinations and the possibility of including small obstacles or terrain roughness has been implemented. In the model, the lander is allowed 6 degrees of freedom. Several landing possibilities are tested with residual velocities and deviations in the starting point, and the stability of the lander is evaluated respect its geometry. Damping strategies have been considered to protect the instruments and reduce the impact, allowing for a safer landing. The effect of including crushable honeycomb dampers in the legs is also implemented, simulated and evaluated, by using a model of crushable honeycombs with different characteristics. In addition, the model includes also the position, direction and characteristics of the thrusters. Thus, it could be used to study other phases of the landing sequence where active control of the lander is needed, and evaluate the behaviour and response of different control-loop algorithms for attitude and position control of the lander.

Jupiter Trojan asteroid dynamics have been studied for a long time but it is only within the last decades that the known population has become large enough to make other studies meaningful. In four articles I have been scratching the surface of the unknown Trojan knowledge space. Paper I presents photometric observations confirming a larger variety in surface redness for the smaller Trojans compared to the larger ones, in line with the groups in the outer main asteroid belt. However, the largest Trojans are significantly redder compared to the largest Cybele and Hilda asteroids. Paper II is an investigation of the Trojan discovery completeness. The analysis shows that all Trojans down to a limiting absolute magnitude of H=11.5 mag have been discovered. Missing Trojans in the almost discovery-completed section should have inclinations above the mean of the same group. The faintest Trojans are discovery biased due to orbit orientations similar to the Milky Way. Paper III is a general review of dynamical and physical properties of the discovery-completed sample of Jupiter Trojans found in Paper II. The two Trojan swarms are often treated as being equal, but are different in a number of details. Two known facts are that the L5 swarm is less rich, while the L4 swarm has a larger fraction of low inclination Trojans. Trojans are in general red objects but the mean redness is higher for Trojans which have not collided compared to Trojans in families. Paper IIII is an investigation of Trojan collisions, family detection and evolution. Collision circumstances were mapped using numerical simulations and recorded Trojan close approaches. Synthetic families were created and evolved numerically. The result suggests that the HCM family detection technique can find Trojan families even in a densely populated parameter space. However, interlopers cannot be avoided at any level but their contribution should be less than 30%. Synthetic families can be identified with backwards orbital integrations for times up to a Gyr-scale. However, there are discrepancies between real Trojan families and my synthetic families.

No description available.

No description available.

This thesis aims towards devising a non-destructive testing methodology for ICs fabricated by a third party manufacturer to ensure the integrity of the chip. With the growing trend of outsourcing, the sanity of the final product has emerged to be a prime concern for the end user. This is especially so if the components are to be used in mission-critical applications such as space-exploration, medical diagnosis and treatment, defense equipment such as missiles etc., where a single failure can lead to a disaster. Thus, any extraneous parts (Trojans) that might have been implanted by the third party manufacturer with a malicious intent during the fabrication process must be diagnosed before the component is put to use. The inherent stealthy nature of Trojans makes it difficult to detect them at normal IC outputs. More so, with the restriction that one cannot visually inspect the internals of an IC after it has been manufactured. This obviates the use of side-channel signal(s) that acts like a signature of the IC as a means to assess its internal behavior under operational conditions. In this work, we have selected power as the side-channel signal to characterize the internal behavior of the ICs. We have used two circuit partitioning based approaches for isolating and enhancing the behavioral difference between parts of a genuine IC and one with a sequence detector Trojan in it. Experimental results reveal that these approaches are effective in exposing anomalous behavior between the targeted ICs. This is reflected as difference in power-profiles of the genuine and maligned ICs that is magnified above the process variation ensuring that the discrepancies are observable. / Master of Science

With the increase in globalization of Integrated Circuit (IC) design and production, hardware trojans have become a serious threat to manufacturers as well as consumers. These trojans could be intensionally or accidentally embedded in ICs to make a system vulnerable to hardware attacks. The implementation of critical applications using ICs makes the effect of trojans an even more serious problem. Moreover, the presence of untrusted foundries and designs cannot be eliminated since the need for ICs is growing exponentially and the use of third party software tools to design the circuits is now common. In addition if a trusted foundry for fabrication has to be developed, it involves a huge investment. Therefore, hardware trojan detection techniques are essential. Very Large Scale Integration (VLSI) system designers must now consider the security of a system against internal and external hardware attacks. Many hardware attacks rely on system vulnerabilities. Moreover, an attacker may rely on deprocessing and reverse engineering to study the internal structure of a system to reveal the system functionality in order to steal secret keys or copy the system. Thus hardware security is a major challenge for the hardware industry. Many hardware attack mitigation techniques have been proposed to help system designers build secure systems that can resist hardware attacks during the design stage, while others protect the system against attacks during operation. In this dissertation, the idea of quantifying hardware attacks, hardware trojans, and hardware trojan detection techniques is introduced. We analyze and classify hardware attacks into risk levels based on three dimensions Accessibility/Resources/Time (ART). We propose a methodology and algorithms to aid the attacker/defender to select/predict the hardware attacks that could use/threaten the system based on the attacker/defender capabilities. Because many of these attacks depends on hardware trojans embedded in the system, we propose a comprehensive hardware trojan classification based on hardware trojan attributes divided into eight categories. An adjacency matrix is generated based on the internal relationship between the attributes within a category and external relationship between attributes in different categories. We propose a methodology to generate a trojan life-cycle based on attributes determined by an attacker/defender to build/investigate a trojan. Trojan identification and severity are studied to provide a systematic way to compare trojans. Trojan detection identification and coverage is also studied to provide a systematic way to compare detection techniques and measure their e effectiveness related to trojan severity. We classify hardware attack mitigation techniques based on the hardware attack risk levels. Finally, we match these techniques to the attacks the could countermeasure to help defenders select appropriate techniques to protect their systems against potential hardware attacks. / Graduate / 0544 / 0984 / samerm@uvic.ca

In this thesis, we study how the planetary migration affects asteroid families. We identify the families among the Trojans of Jupiter by analysing their properties in the space of resonant elements, the size-frequency distribution and the colour indices. The previously reported number of families (10) seems to be overestimated, our analysis indicates that there is only one collisional family among Trojans with the parent-body size DPB > 100 km. We also performed a simulation of the long-term orbital evolution of the Trojan families. We used a modified version of the SWIFT symplectic integrator where the migration is set analytically. We found that the families are unstable even in the late stages of the migration, when Jupiter and Saturn recede from their mutual 1:2 resonance. Hence, the families observed today must have been created after the planetary migration ended. In the last part of the work, we study a formation of asteroid families in the Main Belt during the Late Heavy Bombardement. We simulate perturbations induced by migrating planets in the "jumping Jupiter" scenario (Morbidelli et al., 2010) and we conclude that big families (DPB > 200 km) created during the bombardement should be observable today.

Traditionally, cryptographic algorithms are designed under the so-called black-box model, which considers adversaries that receive black-box access to the hardware implementation. Although a "black-box" treatment covers a wide range of attacks, it fails to capture reality adequately, as real-world adversaries can exploit physical properties of the implementation, mounting attacks that enable unexpected, non-black-box access, to the components of the cryptographic system. This type of attacks is widely known as physical attacks, and has proven to be a significant threat to the real-world security of cryptographic systems. The present dissertation is (partially) dealing with the problem of protecting cryptographic memory against physical attacks, via the use of non-malleable codes, which is a notion introduced in a preceding work, aiming to provide privacy of the encoded data, in the presence of adversarial faults. In the present thesis we improve the current state-of-the-art on non-malleable codes and we provide practical solutions for protecting real-world cryptographic implementations against physical attacks. Our study is primarily focusing on the following adversarial models: (i) the extensively studied split-state model, which assumes that private memory splits into two parts, and the adversary tampers with each part, independently, and (ii) the model of partial functions, which is introduced by the current thesis, and models adversaries that access arbitrary subsets of codeword locations, with bounded cardinality. Our study is comprehensive, covering one-time and continuous, attacks, while for the case of partial functions, we manage to achieve a stronger notion of security, that we call non-malleability with manipulation detection, that in addition to privacy, it also guarantees integrity of the private data. It should be noted that, our techniques are also useful for the problem of establishing, private, keyless communication, over adversarial communication channels. Besides physical attacks, another important concern related to cryptographic hardware security, is that the hardware fabrication process is assumed to be trusted. In reality though, when aiming to minimize the production costs, or whenever access to leading-edge manufacturing facilities is required, the fabrication process requires the involvement of several, potentially malicious, facilities. Consequently, cryptographic hardware is susceptible to the so-called hardware Trojans, which are hardware components that are maliciously implanted to the original circuitry, having as a purpose to alter the device's functionality, while remaining undetected. Part of the present dissertation, deals with the problem of protecting cryptographic hardware against Trojan injection attacks, by (i) proposing a formal model for assessing the security of cryptographic hardware, whose production has been partially outsourced to a set of untrusted, and possibly malicious, manufacturers, and (ii) by proposing a compiler that transforms any cryptographic circuit, into another, that can be securely outsourced.