Showing papers on "Trojan published in 2010"

A Survey of Hardware Trojan Taxonomy and Detection

Abstract: Editor's note:Today's integrated circuits are vulnerable to hardware Trojans, which are malicious alterations to the circuit, either during design or fabrication. This article presents a classification of hardware Trojans and a survey of published techniques for Trojan detection.

Origins and Evolution

Abstract: Having described in the previous chapters the locations and structure of asteroids and dwarf planets, this part of the book shows how they came to be where we find them today and includes: The birth of the Solar System How asteroids formed Where near-Earth asteroids come from Why are there asteroids but no planets between Mars and Jupiter? Planetary satellites The origin of Trojan asteroids Unpredictable Centaurs The Edgeworth–Kuiper Belt (aka trans-Neptunian objects, or TNOs) – knowns and unknowns

Detecting Trojans Through Leakage Current Analysis Using Multiple Supply Pad ${I}_{\rm DDQ}$ s

Abstract: Hardware Trojans have emerged as a new threat to the security and trust of computing systems. Hardware Trojans are deliberate and malicious modifications to the logic function implemented within digital and mixed signal chips. In contrast to software Trojans, it is not possible to simply "scan the hard drive" to eradicate a hardware Trojan. Hardware Trojans can be designed to shutdown the chip at some predetermined time and/or when some specific signal or data pattern is received. They may also be designed to remain hidden while leaking confidential information covertly to the adversary. Determining whether a hardware Trojan has been inserted into a chip is extremely difficult for a variety of reasons, e.g., nanometer feature sizes and chip design complexity combine to make optical inspection difficult or impossible. This paper presents experimental results demonstrating the effectiveness of a Trojan detection method that is based on the analysis of a chip's Jddqs (steady-state current), which are measured simultaneously from multiple places on the chip. The proposed method also incorporates a technique for virtually eliminating process and test environment variations effects which act to reduce detection sensitivity of traditional testing approaches. Used together, resolution enhancements of up to a 1000 x are possible over conventional single power supply current measurement techniques. A regression-based statistical technique is applied to the data collected from a set of chips fabricated in a 65-nm process to illustrate the detection capabilities and limitations of this type of approach.

Multiple-parameter side-channel analysis: A non-invasive hardware Trojan detection approach

Abstract: Malicious alterations of integrated circuits during fabrication in untrusted foundries pose major concern in terms of their reliable and trusted field operation. It is extremely difficult to discover such alterations, also referred to as “hardware Trojans” using conventional structural or functional testing strategies. In this paper, we propose a novel non-invasive, multiple-parameter side-channel analysis based Trojan detection approach that is capable of detecting malicious hardware modifications in the presence of large process variation induced noise. We exploit the intrinsic relationship between dynamic current (I DDT ) and maximum operating frequency (F max ) of a circuit to distinguish the effect of a Trojan from process induced fluctuations in I DDT . We propose a vector generation approach for I DDT measurement that can improve the Trojan detection sensitivity for arbitrary Trojan instances. Simulation results with two large circuits, a 32-bit integer execution unit (IEU) and a 128-bit Advanced Encryption System (AES) cipher, show a detection resolution of 0.04% can be achieved in presence of ±20% parameter (V th ) variations. The approach is also validated with experimental results using 120nm FPGA (Xilinx Virtex-II) chips.

A Sensitivity Analysis of Power Signal Methods for Detecting Hardware Trojans Under Real Process and Environmental Conditions

Abstract: Trust in reference to integrated circuits addresses the concern that the design and/or fabrication of the integrated circuit (IC) may be purposely altered by an adversary. The insertion of a hardware Trojan involves a deliberate and malicious change to an IC that adds or removes functionality or reduces its reliability. Trojans are designed to disable and/or destroy the IC at some future time or they may serve to leak confidential information covertly to the adversary. Trojans can be cleverly hidden by the adversary to make it extremely difficult for chip validation processes, such as manufacturing test, to accidentally discover them. This paper investigates the sensitivity of a power supply transient signal analysis method for detecting Trojans. In particular, we focus on determining the smallest detectable Trojan, i.e., the least number of gates a Trojan may have and still be detected, using a set of process simulation models that characterize a TSMC 0.18 μm process. We also evaluate the sensitivity of our Trojan detection method in the presence of measurement noise and background switching activity.

The Irregular Satellites: The Most Collisionally Evolved Populations in the Solar System

Abstract: The known irregular satellites of the giant planets are dormant comet-like objects that reside on stable prograde and retrograde orbits in a realm where planetary perturbations are only slightly larger than solar ones Their size distributions and total numbers are surprisingly comparable to one another, with the observed populations at Jupiter, Saturn, and Uranus having remarkably shallow power-law slopes for objects larger than 8-10?km in diameter Recent modeling work indicates that they may have been dynamically captured during a violent reshuffling event of the giant planets ~39 billion years ago that led to the clearing of an enormous, 35 M ? disk of comet-like objects (ie, the Nice model) Multiple close encounters between the giant planets at this time allowed some scattered comets near the encounters to be captured via three-body reactions This implies the irregular satellites should be closely related to other dormant comet-like populations that presumably were produced at the same time from the same disk of objects (eg, Trojan asteroids, Kuiper Belt, scattered disk) A critical problem with this idea, however, is that the size distribution of the Trojan asteroids and other related populations do not look at all like the irregular satellites Here we use numerical codes to investigate whether collisional evolution between the irregular satellites over the last ~39 Gyr is sufficient to explain this difference Starting with Trojan asteroid-like size distributions and testing a range of physical properties, we found that our model irregular satellite populations literally self-destruct over hundreds of Myr and lose ~99% of their starting mass The survivors evolve to a low-mass size distribution similar to those observed, where they stay in steady state for billions of years This explains why the different giant planet populations look like one another and provides more evidence that the Nice model may be viable Our work also indicates that collisions produce ~0001 lunar masses of dark dust at each giant planet, and that non-gravitational forces should drive most of it onto the outermost regular satellites We argue that this scenario most easily explains the ubiquitous veneer of dark carbonaceous chondrite-like material seen on many prominent outer planet satellites (eg, Callisto, Titan, Iapetus, Oberon, and Titania) Our model runs also provide strong indications that the irregular satellites were an important, perhaps even dominant, source of craters for many outer planet satellites

Self-referencing: a scalable side-channel approach for hardware Trojan detection

Abstract: Malicious modification of integrated circuits (ICs) in untrusted foundry, referred to as "Hardware Trojan", has emerged as a serious security threat. While side-channel analysis has been reported as an effective approach to detect hardware Trojans, increasing process variations in nanoscale technologies pose a major challenge, since process noise can easily mask the Trojan effect on a measured side-channel parameter, such as supply current. Besides, existing side-channel approaches suffer from reduced Trojan detection sensitivity with increasing design size. In this paper, we propose a novel scalable side-channel approach, named self-referencing, along with associated vector generation algorithm to improve the Hardware Trojan detection sensitivity under large process variations. It compares transient current signature of one region of an IC with that of another, thereby nullifying the effect of process noise by exploiting spatial correlation across regions in terms of process variations. To amplify the Trojan effect on supply current, we propose a region-based vector generation approach, which divides a circuit-undertest (CUT) into several regions and for each region, finds the test vectors which induce maximum activity in that region, while minimizing the activity in other regions. We show that the proposed side-channel approach is scalable with respect to both amount of process variations and design size. The approach is validated with both simulation and measurement results using an FPGA-based test setup for large designs including a 32-bit DLX processor core (∼ 105 transistors). Results shows that our approach can find ultra-small (<0.01% area) Trojans under large process variations of up to ± 20% shift in transistor threshold voltage.

The capture of Trojan asteroids by the giant planets during planetary migration

Abstract: Of the four giant planets in the Solar system, only Jupiter and Neptune are currently known to possess swarms of Trojan asteroids - small objects that experience a 1:1 mean motion resonance with their host planet. In Lykawka et al., we performed extensive dynamical simulations, including planetary migration, to investigate the origin of the Neptunian Trojan population. Utilizing the vast amount of simulation data obtained for that work, together with fresh results from new simulations, we here investigate the dynamical capture of Trojans by all four giant planets from a primordial trans-Neptunian disc. We find the likelihood of a given planetesimal from this region being captured on to an orbit within Jupiter's Trojan cloud lies between several times 10-6 and 10-5. For Saturn, the probability is found to be in the range <10-6 to 10-5, whilst for Uranus the probabilities range between 10-5 and 10-4. Finally, Neptune displays the greatest probability of Trojan capture, with values ranging between 10-4 and 10-3. Our results suggest that all four giant planets are able to capture and retain a significant population of Trojan objects from the disc by the end of planetary migration. As a result of encounters with the giant planets prior to Trojan capture, these objects tend to be captured on orbits that are spread over a wide range of orbital eccentricities and inclinations. The bulk of captured objects are to some extent dynamically unstable, and therefore, the populations of these objects tend to decay over the age of the Solar system, providing an important ongoing source of new objects moving on dynamically unstable orbits among the giant planets. Given that a huge population of objects would be displaced by Neptune's outward migration (with a potential cumulative mass a number of times that of the Earth), we conclude that the surviving remnant of the Trojans captured during the migration of the outer planets might be sufficient to explain the currently known Trojan populations in the outer Solar system.

The Neptune Trojans – a new source for the Centaurs?

Abstract: The fact that the Centaurs are the primary source of the short-period comets is well established. However, the origin of the Centaurs themselves is still under some debate, with a variety of different source reservoirs being proposed in the last decade. In this work, we suggest that the Neptune Trojans (together with the Jovian Trojans) could represent an additional significant source of Centaurs. Using dynamical simulations of the first Neptune Trojan discovered (2001 QR322), together with integrations following the evolution of clouds of theoretical Neptune Trojans obtained during simulations of planetary migration, we show that the Neptune Trojan population contains a great number of objects which are unstable on both Myr and Gyr time-scales. Using individual examples, we show how objects that leave the Neptunian Trojan cloud evolve on to orbits indistinguishable from those of the known Centaurs, before providing a range of estimates of the flux from this region to the Centaur population. With only moderate assumptions, it is shown that the Trojans can contribute a significant proportion of the Centaur population, and may even be the dominant source reservoir. This result is supported by past work on the colours of the Trojans and the Centaurs, but it will take future observations to determine the full scale of the contribution of the escaped Trojans to the Centaur population.

A layout-aware approach for improving localized switching to detect hardware Trojans in integrated circuits

Abstract: Malicious activities and alterations to integrated circuits have raised serious concerns to government agencies and the semiconductor industry The added functionality, known as hardware Trojan, poses major detection and isolation challenges In this paper, we present a method to localize design switching to any specific region independent from test patterns The new architecture allows activating any target region and keeping others quiet which reduces total circuit switching activity This helps magnify the Trojan's contribution to the total circuit transient power by increasing Trojan-to-circuit switching activity (TCA) and power consumption The proposed method is aimed at improving the efficiency of power-based side-channel signal analysis techniques for detecting hardware Trojans Our simulation results demonstrate the efficiency of the method in significantly increasing TCA

2001 QR322: a dynamically unstable Neptune Trojan?

Abstract: Since early work on the stability of the first Neptunian Trojan, 2001 QR322, suggested that it was a dynamically stable, primordial body, it has been assumed that this applies to both that object and its more recently discovered brethren. However, it seems that things are no longer so clear-cut. In this work, we present the results of detailed dynamical simulations of the orbital behaviour of 2001 QR322. Using an ephemeris for the object that has significantly improved since earlier works, we follow the evolution of 19683 test particles, placed on orbits within the observational error ellipse of 2001 QR322's orbit, for a period of 1Gyr. We find that majority of these `clones' of 2001 QR322 are dynamically unstable, exhibiting a near-exponential decay from both the Neptunian Trojan cloud (decay half-life of ~550Myr) and the Solar system (decay half-life of ~590Myr). The stability of the object within Neptune's Trojan cloud is found to be strongly dependent on the initial semi major axis used, with these objects located at a >= 30.30au being significantly less stable than those interior to this value, as a result of their having initial libration amplitudes very close to a critical threshold dividing regular and irregular motion, located at ~70°-75° (full extent of angular motion). This result suggests that if 2001 QR322 is a primordial Neptunian Trojan, it must be a representative of a population that was once significantly larger than that we see today and adds weight to the idea that the Neptune Trojans may represent a significant source of objects moving on unstable orbits between the giant planets (the Centaurs).

Detection of a Trailing (L5) Neptune Trojan

Abstract: The orbits of small Solar System bodies record the history of our Solar System. Here, we report the detection of 2008 LC18, which is a Neptune Trojan in the trailing (L5) Lagrangian region of gravitational equilibrium within Neptune's orbit. We estimate that the leading and trailing Neptune Trojan regions have similarly sized populations and dynamics, with both regions dominated by high-inclination objects. Similar populations and dynamics at both Neptune Lagrangian regions indicate that the Trojans were likely captured by a migrating, eccentric Neptune in a dynamically excited planetesimal population.

Where are the Uranus Trojans

Abstract: The area of stable motion for fictitious Trojan asteroids around Uranus’ equilateral equilibrium points is investigated with respect to the inclination of the asteroid’s orbit to determine the size of the regions and their shape. For this task we used the results of extensive numerical integrations of orbits for a grid of initial conditions around the points L 4 and L 5, and analyzed the stability of the individual orbits. Our basic dynamical model was the Outer Solar System (Jupiter, Saturn, Uranus and Neptune). We integrated the equations of motion of fictitious Trojans in the vicinity of the stable equilibrium points for selected orbits up to the age of the Solar system of 5 × 109 years. One experiment has been undertaken for cuts through the Lagrange points for fixed values of the inclinations, while the semimajor axes were varied. The extension of the stable region with respect to the initial semimajor axis lies between 19.05 ≤ a ≤ 19.3 AU but depends on the initial inclination. In another run the inclination of the asteroids’ orbit was varied in the range 0° < i < 60° and the semimajor axes were fixed. It turned out that only four ‘windows’ of stable orbits survive: these are the orbits for the initial inclinations 0° < i < 7°, 9° < i < 13°, 31° < i < 36° and 38° < i < 50°. We postulate the existence of at least some Trojans around the Uranus Lagrange points for the stability window at small and also high inclinations.

Formation and dynamical evolution of the Neptune Trojans - the influence of the initial Solar system architecture

Abstract: Current models of Solar system formation suggest that the four giant planets accreted as a significantly more compact system than we observe today. In this work, we investigate the dynamical stability of pre-formed Neptune Trojans under the gravitational influence of the four giant planets in compact planetary architectures, over 10 Myr. In our modelling, the initial orbital locations of Uranus and Neptune (aN) were varied to produce systems in which those planets moved on non-resonant orbits or in which they lay in their mutual 1:2, 2:3 and 3:4 mean-motion resonances (MMRs). In total, 420 simulations were carried out, examining 42 different architectures, with a total of 840000 particles across all runs. In the non-resonant cases, the Trojans suffered only moderate levels of dynamical erosion, with the most compact systems (those with aN <= 18 au) losing around 50 per cent of their Trojans by the end of the integrations. In the 2:3 and 3:4 MMR scenarios, however, dynamical erosion was much higher with depletion rates typically greater than 66 per cent and total depletion in the most compact systems. The 1:2 resonant scenarios featured disruption on levels intermediate between the non-resonant cases and other resonant scenarios, with depletion rates of the order of tens of per cent. Overall, the great majority of plausible pre-migration planetary architectures resulted in severe levels of depletion of the Neptunian Trojan clouds. In particular, if Uranus and Neptune formed near their mutual 2:3 or 3:4 MMR and at heliocentric distances within 18au (as favoured by recent studies), we found that the great majority of pre-formed Trojans would have been lost prior to Neptune's migration. This strengthens the case for the great bulk of the current Neptunian Trojan population having been captured during that migration.

DFTT: Design for Trojan Test

Abstract: Due to the globalization of the Integrated Circuit (IC) manufacturing industry, hardware Trojans constitute an increasingly probable threat to both commercial and military applications. As traditional testing methods fall short in finding hardware Trojans, several specialized detection methods have surfaced. To facilitate research in this area and embed internal barriers to prevent Trojan attacks both at the design level and at the manufacturing level, we propose a Design-for-Trojan-Test (DFTT) methodology. DFTT is based on one key principle: increase the complexity for hardware Trojan attackers, thereby making successful hardware Trojan-based attacks extremely difficult to accomplish. A DFTT tool is also developed to automate the hardening process. The effectiveness of our Trojan prevention method is demonstrated on the Trivium encryption core.

Planetary Trojans: the main source of short period comets?

Abstract: One of the key considerations when assessing the potential habitability of telluric worlds will be that of the impact regime experienced by the planet. In this work, we present a short review of our understanding of the impact regime experienced by the terrestrial planets within our own Solar system, describing the three populations of potentially hazardous objects which move on orbits that take them through the inner Solar system. Of these populations, the origins of two (the Near-Earth Asteroids and the Long-Period Comets) are well understood, with members originating in the Asteroid belt and Oort cloud, respectively. By contrast, the source of the third population, the Short-Period Comets, is still under debate. The proximate source of these objects is the Centaurs, a population of dynamically unstable objects that pass perihelion (closest approach to the Sun) between the orbits of Jupiter and Neptune. However, a variety of different origins have been suggested for the Centaur population. Here, we present evidence that at least a significant fraction of the Centaur population can be sourced from the planetary Trojan clouds, stable reservoirs of objects moving in 1:1 mean-motion resonance with the giant planets (primarily Jupiter and Neptune). Focussing on simulations of the Neptunian Trojan population, we show that an ongoing flux of objects should be leaving that region to move on orbits within the Centaur population. With conservative estimates of the flux from the Neptunian Trojan clouds, we show that their contribution to that population could be of order ~3%, while more realistic estimates suggest that the Neptune Trojans could even be the main source of fresh Centaurs. We suggest that further observational work is needed to constrain the contribution made by the Neptune Trojans to the ongoing flux of material to the inner Solar system, and believe that future studies of the habitability of exoplanetary systems should take care not to neglect the contribution of resonant objects (such as planetary Trojans) to the impact flux that could be experienced by potentially habitable worlds.

Origin and Dynamical Evolution of Neptune Trojans - II: Long Term Evolution

Abstract: We present results examining the fate of the Trojan clouds produced in our previous work. We find that the stability of Neptunian Trojans seems to be strongly correlated to their initial post-migration orbital elements, with those objects that survive as Trojans for billions of years displaying negligible orbital evolution. The great majority of these survivors began the integrations with small eccentricities (e 20°. Dynamical integrations of the currently observed Trojans show that five out of the seven are dynamically stable on 4 Gyr timescales, while 2001 QR322, exhibits significant dynamical instability. The seventh Trojan object, 2008 LC18, has such large orbital uncertainties that only future studies will be able to determine its stability.

An Introduction to the Dynamics of Trojan Asteroids

Abstract: The dynamics of Trojan asteroids constitutes one of the richest fields of celestial mechanics, as a real application of the three-body problem. It involves the L 4 and L 5 Lagrange points and the conditions of stability around these two points. In this chapter we propose to present the fundamentals of the dynamics of Trojan asteroids. After a brief historical overview, we come back to the definitions and characteristics of the collinear Lagrange points L 1, L 2, and L 3, as well as the triangular ones, L 4 and L 5. We show how observational data of Trojan asteroids have confirmed the existence of real bodies librating around these two last points. Then we focus on the linearization of the equations of motion around L 4 and L 5 from a general and purely theoretical point of view. In addition, we show how qualitative results can be extracted to describe the properties of Trojan asteroids. We complete our study by summarizing many previous and up-to-date investigations, which focus on their dynamical behavior.

Method for automatically positioning webpage Trojan mount point in Trojan linked webpage

Abstract: The invention discloses a method for automatically positioning webpage Trojan mount point in a Trojan linked webpage and belongs to the field of computer security. The method comprises the following steps of: a) determining the Trojan linking webpage; b) acquiring a style sheet in the Trojan linked webpage, and performing script analysis on the scripts therein according to a step c); c) acquiringthe scripts in the Trojan linked webpage, outputting the positions of malicious scripts in a father webpage, wherein the malicious characteristics comprise: calling the objects of known bugs, containing malicious codes, opening malicious webpages, redirecting to the malicious webpages, and adding malicious webpages; and d) acquiring an embedded webpage in the Trojan linked webpage, comparing whether the website domain name is the same as the Trojan linked webpage for the embedded webpage determined to be subjected to Trojan linkage, if so, performing recursive analysis, otherwise, outputting the position of an embedded label in the father webpage. The method can be applied to the computer security, and comprises rapidly positioning the mount position of the webpage Trojan in the webpage to assist the website management personnel to rapidly remove the malicious contents contained in the webpage.

Hardware trojans for inducing or amplifying side-channel leakage of cryptographic software

Abstract: Malicious alterations of integrated circuits (ICs), introduced during either the design or fabrication process, are increasingly perceived as a serious concern by the global semiconductor industry. Such rogue alterations often take the form of a “hardware Trojan,” which may be activated from remote after the compromised chip or system has been deployed in the field. The devious actions of hardware Trojans can range from the disabling of all or part of the chip (i.e. “kill switch”), over the activation of a backdoor that allows an adversary to gain access to the system, to the covert transmission of sensitive information (e.g. cryptographic keys) off-chip. In the recent past, hardware Trojans which induce side-channel leakage to convey secret keys have received considerable attention. With the present paper we aim to broaden the scope of Trojan side-channels from dedicated cryptographic hardware to general-purpose processors on which cryptographic software is executed. In particular, we describe a number of simple micro-architectural modifications to induce or amplify information leakage via faulty computations or variations in the latency and power consumption of certain instructions. We also propose software-based mechanisms for Trojan activation and present two case studies to exemplify the induced side-channel leakage for software implementations of RSA and AES. Finally, we discuss a constructive use of micro-architectural Trojans for digital watermarking so as to facilitate the detection of illegally manufactured copies of processors.

Reuse-oriented camouflaging trojan: Vulnerability detection and attack construction

Abstract: We introduce the reuse-oriented camouflaging trojan — a new threat to legitimate software binaries. To perform a malicious action, such a trojan identifies and reuses an existing function in a legal binary program instead of implementing the function itself. Furthermore, this trojan is stealthy in that the malicious invocation of a targeted function usually takes place in a location where it is legal to do so, closely mimicking a legal invocation. At the network level, the victim binary can still follow its communication protocol without exhibiting any anomalous behavior. Meanwhile, many close-source shareware binaries are rich in functions that can be maliciously “reused”, making them attractive targets of this type of attack. In this paper, we present a framework to determine if a given binary program is vulnerable to this attack and to construct a concrete trojan if so. Our experiments with a number of real-world software binaries demonstrate that the reuse-oriented camouflaging trojans are a real threat and vulnerabilities of this type in legal binaries can be effectively revealed and confirmed.

A unified submodular framework for multimodal IC Trojan detection

Abstract: This paper presents a unified formal framework for integrated circuits (IC) Trojan detection that can simultaneously employ multiple noninvasive measurement types. Hardware Trojans refer to modifications, alterations, or insertions to the original IC for adversarial purposes. The new framework formally defines the IC Trojan detection for each measurement type as an optimization problem and discusses the complexity. A formulation of the problem that is applicable to a large class of Trojan detection problems and is submodular is devised. Based on the objective function properties, an efficient Trojan detection method with strong approximation and optimality guarantees is introduced. Signal processing methods for calibrating the impact of interchip and intra-chip correlations are presented. We propose a number of methods for combining the detections of the different measurement types. Experimental evaluations on benchmark designs reveal the low-overhead and effectiveness of the new Trojan detection framework and provides a comparison of different detection combining methods.

Detecting Trojan horses based on system behavior using machine learning method

Abstract: The Research of detection malware using machine learning method attracts much attention recent years. However, most of research focused on code analysis which is signature-based or analysis of system call sequence in Linux environment. Obviously, all methods have their strengths and weaknesses. In this paper, we concentrate on detection Trojan horse by operation system information in Windows environment using data mining technology. Our main content and contribution contains as follows: First, we collect Trojan horse samples in true network environment and classify them by scanner. Secondly, we collect operation system behavior features under infected and clean circumstances separately by WMI manager tools. And then, several classic classification algorithms are applied and a performance comparison is given. Feature selection methods are applied to those features and we get a feature order list which reflects the relevance order of Trojan horse activities and the system feature. We believe the instructive meaning of the list is significant. Finally, a feature combination method is applied and features belongs different groups are combined according their characteristic for high classification performance. Results of experiments demonstrate the feasibility of our assumption that detecting Trojan horses by system behavior information is feasible and affective.

Planetary Trojans - the main source of short period comets?

Abstract: We present a short review of the impact regime experienced by the terrestrial planets within our own Solar system, describing the three populations of potentially hazardous objects which move on orbits that take them through the inner Solar system. Of these populations, the origins of two (the Near-Earth Asteroids and the Long-Period Comets) are well understood, with members originating in the Asteroid belt and Oort cloud, respectively. By contrast, the source of the third population, the Short-Period Comets, is still under debate. The proximate source of these objects is the Centaurs, a population of dynamically unstable objects that pass perihelion between the orbits of Jupiter and Neptune. However, a variety of different origins have been suggested for the Centaur population. Here, we present evidence that at least a significant fraction of the Centaur population can be sourced from the planetary Trojan clouds, stable reservoirs of objects moving in 1:1 mean-motion resonance with the giant planets (primarily Jupiter and Neptune). Focusing on simulations of the Neptunian Trojan population, we show that an ongoing flux of objects should be leaving that region to move on orbits within the Centaur population. With conservative estimates of the flux from the Neptunian Trojan clouds, we show that their contribution to that population could be of order ~3%, while more realistic estimates suggest that the Neptune Trojans could even be the main source of fresh Centaurs. We suggest that further observational work is needed to constrain the contribution made by the Neptune Trojans to the ongoing flux of material to the inner Solar system, and believe that future studies of the habitability of exoplanetary systems should take care not to neglect the contribution of resonant objects (such as planetary Trojans) to the impact flux that could be experienced by potentially habitable worlds.

Searching for trojan asteroids in the hd 209458 system: space-based most photometry and dynamical modeling

Abstract: We have searched Microvariability and Oscillations of Stars (MOST) satellite photometry obtained in 2004, 2005, and 2007 of the solar-type star HD 209458 for Trojan asteroid swarms dynamically coupled with the system's transiting hot Jupiter HD 209458b. Observations of the presence and nature of asteroids around other stars would provide unique constraints on migration models of exoplanetary systems. Our results set an upper limit on the optical depth of Trojans in the HD 209458 system that can be used to guide current and future searches of similar systems by upcoming missions. Using cross-correlation methods with artificial signals implanted in the data, we find that our detection limit corresponds to a relative Trojan transit depth of 1 ×10–4, equivalent to ~1 lunar mass of asteroids, assuming power-law Trojan size distributions similar to Jupiter's Trojans in our solar system. We confirm with dynamical interpretations that some asteroids could have migrated inward with the planet to its current orbit at 0.045 AU, and that the Yarkovsky effect is ineffective at eliminating objects of >1 m in size. However, using numerical models of collisional evolution we find that, due to high relative speeds in this confined Trojan environment, collisions destroy the vast majority of the asteroids in <10 Myr. Our modeling indicates that the best candidates to search for exoTrojan swarms in 1:1 mean resonance orbits with hot Jupiters are young systems (ages of about 1 Myr or less). Years of Kepler satellite monitoring of such a system could detect an asteroid swarm with a predicted transit depth of 3 × 10–7.

Searching for Trojan Asteroids in the HD 209458 System: Space-based MOST Photometry and Dynamical Modeling

Abstract: We have searched Microvariability and Oscillations of STars (MOST) satellite photometry obtained in 2004, 2005, and 2007 of the solar-type star HD 209458 for Trojan asteroid swarms dynamically coupled with the system's transiting "hot Jupiter" HD 209458b. Observations of the presence and nature of asteroids around other stars would provide unique constraints on migration models of exoplanetary systems. Our results set an upper limit on the optical depth of Trojans in the HD 209458 system that can be used to guide current and future searches of similar systems by upcoming missions. Using cross-correlation methods with artificial signals implanted in the data, we find that our detection limit corresponds to a relative Trojan transit depth of 1\times10-4, equivalent to ~1 lunar mass of asteroids, assuming power-law Trojan size distributions similar to Jupiter's Trojans in our solar system. We confirm with dynamical interpretations that some asteroids could have migrated inward with the planet to its current orbit at 0.045 AU, and that the Yarkovsky effect is ineffective at eliminating objects of > 1 m in size. However, using numerical models of collisional evolution we find that, due to high relative speeds in this confined Trojan environment, collisions destroy the vast majority of the asteroids in <10 Myr. Our modeling indicates that the best candidates to search for exoTrojan swarms in 1:1 mean resonance orbits with "hot Jupiters" are young systems (ages of about 1 Myr or less). Years of Kepler satellite monitoring of such a system could detect an asteroid swarm with a predicted transit depth of 3\times10-7.

Method and device for detecting Trojans by analyzing network behaviors

Abstract: The invention relates to a method and a device for detecting Trojans by analyzing network behaviors. The Trojans are detected by analyzing and comparing behavior characteristics. The method comprises the following steps of: searching the network behaviors in a local area network; analyzing the representative behavior characteristics of the network behaviors, and detecting the Trojans in real time through the network behaviors such as external linkage of the Trojans, information stealing and outbound information. The device consists of an acquisition device and an analyzer, wherein the acquisition device acquires a network data packet and sends the network data packet to the analyzer; the analyzer reorganizes data, extracts the representative behavior characteristic of the data, performs correlation analysis with a Trojan characteristic library, generates a security event report and presents the security event report to a fore system. The Trojans are detected by using behavior characteristic analysis technology; and compared with the conventional program characteristic code comparison technology, the method of the invention has the advantages of capability of detecting the Trojans in known types and in unknown types, and good detection effect particularly for mutation and variation such as packed and kill-free Trojans.

Simulated webpage Trojan detecting method based on ActiveX component

Abstract: The invention discloses a simulated webpage Trojan detecting method based on an ActiveX component, comprising the following steps: (1) build an ActiveX component M, an object instance m of the ActiveX component M is used for simulating a component N which is missed in a target webpage; (2) write a dynamic link library to hook an API which is in charge of creating the component M in a WINDOWS system, record the corresponding relationship between the entry address of the object instance m of the component M and the component name of the component N; (3) invoke a browser to browse the target webpage, when the target webpage requests to create the missed component N, record the component name, functions in the component and parameter information which are visited by the target webpage to a log file by the object instance m; (4) analyze the log file, judge whether the target webpage is a webpage Trojan or not. The simulated webpage Trojan detecting method based on the ActiveX component can simulate a plug-in in which a bug may exists, more attack behaviors of the webpage Trojan can be triggered, and the attack behaviors in an ActiveX component invoking layer of the webpage Trojan can be obtained.

Trustworthy computing in a multi-core system using distributed scheduling

Abstract: Hardware Trust is an emerging problem in semiconductor integrated circuit (IC) security due to widespread outsourcing and the stealthy nature of hardware Trojans. Conventional post-manufacturing testing, test generation algorithms and test coverage metrics cannot be readily extended to hardware Trojan detection. As a result there is a need to develop approaches that will ensure trusted in-field operation of ICs, and more generally trust in computing. We present a distributed software scheduling prototype, TADS (Trojan Aware Distributed Scheduling), to achieve a Trojan-activation tolerant trustworthy computing system in a multi-core processor potentially containing hardware Trojans. TADS is designed to be transparent to applications and can run on general purpose multicore PEs without modifications to the operating system or underlying hardware. TADS can, with high confidence, continue to correctly execute its specified queue of job subtasks in the presence of hardware Trojans in the multi-core PEs while learning the individual trustworthiness of the individual PEs. Specially crafted self-checking subtasks called bounty hunters are introduced to accelerate PE trust learning. Also, by learning and maintaining individual PE trustworthiness, the scheduler is able to achieve Trojan containment by scheduling subsequent job subtasks to PEs with high learned trust.