Biblio

The threat of inserting malicious logic in hardware design is increasing as the digital supply chains are becoming more deep and span the whole globe. Ring oscillators (ROs) can be used to detect deviations of circuit operations due to changes of its layout caused by the insertion of a hardware Trojan horse (Trojan). The placement and the length of the ring oscillator are two important parameters that define an RO sensitivity and capability to detect malicious alternations. We propose and study the use of ring oscillators with variable lengths, configurable at the runtime. Such oscillators push further the envelope for the attackers, as their design must be undetectable by all supported lengths. We study the efficiency of our proposal on defending against a family of hardware Trojans against an implementation of the AES cryptographic algorithm on an FPGA.

The success or failure of a mobile application (`app') is largely determined by user ratings. Users frequently make their app choices based on the ratings of apps in comparison with similar, often competing apps. Users also expect apps to continually provide new features while maintaining quality, or the ratings drop. At the same time apps must also be secure, but is there a historical trade-off between security and ratings? Or are app store ratings a more all-encompassing measure of product maturity? We used static analysis tools to collect security-related metrics in 38,466 Android apps from the Google Play store. We compared the rate of an app's permission misuse, number of requested permissions, and Androrisk score, against its user rating. We found that high-rated apps have statistically significantly higher security risk metrics than low-rated apps. However, the correlations are weak. This result supports the conventional wisdom that users are not factoring security risks into their ratings in a meaningful way. This could be due to several reasons including users not placing much emphasis on security, or that the typical user is unable to gauge the security risk level of the apps they use everyday.

Federated cloud networks are formed by federating virtual network segments from different clouds, e.g. in a hybrid cloud, into a single federated network. Such networks should be protected with a global federated cloud network security policy. The availability of network function virtualisation and service function chaining in cloud platforms offers an opportunity for implementing and enforcing global federated cloud network security policies. In this paper we describe an approach for enforcing global security policies in federated cloud networks. The approach relies on a service manifest that specifies the global network security policy. From this manifest configurations of the security functions for the different clouds of the federation are generated. This enables automated deployment and configuration of network security functions across the different clouds. The approach is illustrated with a case study where communications between trusted and untrusted clouds, e.g. public clouds, are encrypted. The paper discusses future work on implementing this architecture for the OpenStack cloud platform with the service function chaining API.

Recently, PIN-TRUST, a method to predict future trust relationships between users is proposed. PIN-TRUST out-performs existing trust prediction methods by exploiting all types of interactions between users and the reciprocation of ones. In this paper, we validate whether its consideration on the reciprocation of interactions is really effective in trust prediction. Furthermore, we consider a new concept, the "uncertainty" of untrustworthy users that is devised to reflect the difficulty on modeling the activities of untrustworthy users in PIN-TRUST. Then, we also validate the effectiveness this uncertainty concepts. Through the validation, we reveal that the consideration of the reciprocation of interactions is effective for trust prediction with PIN-TRUST, and it is necessary to regard the uncertainty of untrustworthy users same as that of other users.

The software-as-a-service (SaaS) market is growing very fast, but still many clients are concerned about the confidentiality of their data in the cloud. Motivated hackers or malicious insiders could try to steal the clients' data. Encryption is a potential solution, but supporting the necessary functionality also in existing applications is difficult. In this paper, we examine encrypting analytical web applications that perform extensive number processing operations in the database. Existing solutions for encrypting data in web applications poorly support such encryption. We employ a proxy that adjusts the encryption to the level necessary for the client's usage and also supports additively homomorphic encryption. This proxy is deployed at the client and all encryption keys are stored and managed there, while the application is running in the cloud. Our proxy is stateless and we only need to modify the database driver of the application. We evaluate an instantiation of our architecture on an exemplary application. We only slightly increase page load time on average from 3.1 seconds to 4.7. However, roughly 40% of all data columns remain probabilistic encrypted. The client can set the desired security level for each column using our policy mechanism. Hence our proxy architecture offers a solution to increase the confidentiality of the data at the cloud provider at a moderate performance penalty.

This paper describes a study that investigates tilt-gesture depth on a Bluetooth handheld music controller for activating and deactivating music loops. Making use of a Wii Remote's 3-axis ADXL330 accelerometer, a Max patch was programmed to receive, handle, and store incoming accelerometer data. Each loop corresponded to the front, back, left and right tilt-gesture direction, with each gesture motion triggering a loop 'On' or 'Off' depending on its playback status. The study comprised 40 undergraduate students interacting with the prototype controller for a duration of 5 minutes per person. Each participant performed three full cycles beginning with the front gesture direction and moving clockwise. This corresponded to a total of 24 trigger motions per participant. Raw data associated with tilt-gesture motion depth was scaled, analyzed and graphed. Results show significant differences between each gesture direction in terms of tilt-gesture depth, as well as issues with noise for left/right gesture motion due to dependency on Roll and Yaw values. Front and Left tilt-gesture depths displayed significantly higher threshold levels compared to the Back and Right axes. Front and Left tilt-gesture thresholds therefore allow the device to easily differentiate between intentional sample triggering and general device handling, while this is more difficult for Back and Left directions. Future work will include finding an alternative method for evaluating intentional tilt-gesture triggering on the Back and Left axes, as well as utilizing two 2-axis accelerometers to garner clean data from the Left and Right axes.

In this research paper, we present a function-based methodology to evaluate the resilience of gas pipeline systems under two different cyber-physical attack scenarios. The first attack scenario is the pressure integrity attack on the natural gas high-pressure transmission pipeline. Through simulations, we have analyzed the cyber attacks that propagate from cyber to the gas pipeline physical domain, the time before which the SCADA system should respond to such attacks, and finally, an attack which prevents the response of the system. We have used the combined results of simulations of a wireless mesh network for remote terminal units and of a gas pipeline simulation to measure the shortest Time to Criticality (TTC) parameter; the time for an event to reach the failure state. The second attack scenario describes how a failure of a cyber node controlling power grid functionality propagates from cyber to power to gas pipeline systems. We formulate this problem using a graph-theoretic approach and quantify the resilience of the networks by percentage of connected nodes and the length of the shortest path between them. The results show that parameters such as TTC, power distribution capacity of the power grid nodes and percentage of the type of cyber nodes compromised, regulate the efficiency and resilience of the power and gas networks. The analysis of such attack scenarios helps the gas pipeline system administrators design attack remediation algorithms and improve the response of the system to an attack.

The Internet of Things (IoT) is a design implementation of embedded system design that connects a variety of devices, sensors, and physical objects to a larger connected network (e.g. the Internet) which requires human-to-human or human-to-computer interaction. While the IoT is expected to expand the user's connectivity and everyday convenience, there are serious security considerations that come into account when using the IoT for distributed authentication. Furthermore the incorporation of biometrics to IoT design brings about concerns of cost and implementing a 'user-friendly' design. In this paper, we focus on the use of electrocardiogram (ECG) signals to implement distributed biometrics authentication within an IoT system model. Our observations show that ECG biometrics are highly reliable, more secure, and easier to implement than other biometrics.

Most augmented reality applications connect virtual information to anchors, i.e. physical places or objects, by using spatial overlays or proximity. However, for industrial use cases this is not always feasible because specific parts must remain fully visible in order to meet work or security requirements. In these situations virtual information must be displayed at alternative positions while connections to anchors must still be clearly recognizable. In our previous research we were the first to show that for simple scenes connection lines are most suitable for this. To extend these results to more complex environments, we conducted an experiment on the effects of visual interruptions in connection lines and incorrect occlusion. Completion time and subjective mental effort for search tasks were used as measures. Our findings confirm that also in 3D scenes with partial occlusion connection lines are preferable to connect virtual information with anchors if an assignment via overlay or close proximity is not feasible. The results further imply that neither incorrectly used depth cues nor missing parts of connection lines make a significant difference concerning completion time or subjective mental effort. For designers of industrial augmented reality applications this means that they can choose either visualization based on their needs.

The objective of this work is to develop an efficient and practical sensor placement method for the failure detection and localization in water networks. We formulate the problem as the minimum test cover problem (MTC) with the objective of selecting the minimum number of sensors required to uniquely identify and localize pipe failure events. First, we summarize a single-level sensing model and discuss an efficient fast greedy approach for solving the MTC problem. Simulation results on benchmark test networks demonstrate the efficacy of the fast greedy algorithm. Second, we develop a multi-level sensing model that captures additional physical features of the disturbance event, such as the time lapsed between the occurrence of disturbance and its detection by the sensor. Our sensor placement approach using MTC extends to the multi-level sensing model and an improved identification performance is obtained via reduced number of sensors (in comparison to single-level sensing model). In particular, we investigate the bi-level sensing model to illustrate the efficacy of employing multi-level sensors for the identification of failure events. Finally, we suggest extensions of our approach for the deployment of heterogeneous sensors in water networks by exploring the trade-off between cost and performance (measured in terms of the identification score of pipe/link failures).

In this paper, we present a fundamental limitation of disturbance attenuation in discrete-time single-input single-output (SISO) feedback systems when the controller has delayed side information about the external disturbance. Specifically, we assume that the delayed information about the disturbance is transmitted to the controller across a finite Shannon-capacity communication channel. Our main result is a lower bound on the log sensitivity integral in terms of open-loop unstable poles of the plant and the characteristics of the channel, similar to the classical Bode integral formula. A comparison with prior work that considers the effect of preview side information of the disturbance at the controller indicates that delayed side information and preview side information play different roles in disturbance attenuation. In particular, we show that for open-loop stable systems, delayed side information cannot reduce the log integral of the sensitivity function whereas it can for open-loop unstable systems, even when the disturbance is a white stochastic process.

We proposed a multi-granularity approach to present risk information of mobile apps to the end users. Within this approach the highest level is a summary risk index, which allows quick and easy comparison among multiple apps that provide similar functionality. We have developed several types of risk index, such as text saying “High Risk” or number of filled circles (Gates, Chen, Li, & Proctor, 2014). Through both online and in-lab studies, we found that when presented the interface with the summary risk index, participants made more secure app-selection decisions. Subsequent research showed that framing of the summary risk information affects users’ app-selection decisions, and positive framing in terms of safety has an advantage over negative framing in terms of risk (Chen, Gates, Li, & Proctor, 2014).

In addition to the summary risk index, some users may also want more detailed risk information for the apps. We have been developing an intermediate-level risk display that presents only the major risk categories. As a first step, we conducted user studies to have expert users’ identify the major risk categories (personal privacy, monetary loss, and device stability) and validate the categories on typical users (Jorgensen, Chen, Gates, Li, Proctor, & Yu, 2015). In a subsequent study, we are developing a graphical display to incorporate these risk categories into the current app interface and test its effectiveness.

This multi-granularity approach can be applied to risk communication in other contexts. For example, in the context of communicating the potential risk associated with phishing attacks, an effective warning should be designed to include both higher-level and lower-level risk information: A higher-level index information about how likely an email message or website is a phishing one should be presented to users and inform them about the potential risk in an easy-to-comprehend manner; a more detailed explanation should also be available for users who want to know more about the warning and the index. We have completed a pilot study in this area and are initiating a full study to investigate the effectiveness of such an interface in preventing users from being phished successfully.

We have begun to investigate the effectiveness of a phishing warning Chrome extension in a field setting of everyday computer use. A preliminary experiment has been conducted in which participants installed and used the extension. They were required to fill out an online browsing behavior questionnaire by clicking on a survey link sent in a weekly email by us. Two phishing attacks were simulated during the study by directing participants to "fake" (phishing) survey sites we created. Almost all participants who saw the warnings on our fake sites input incorrect passwords, but follow-up interviews revealed that only one participant did so intentionally. A follow-up interview revealed that the warning failure was mainly due to the survey task being mandatory. Another finding of interest from the interview was that about 50% of the participants had never heard of phishing or did not understand its meaning.

The objective of this work is to develop an efficient and practical sensor placement method for the failure detection and localization in water networks. We formulate the problem as the minimum test cover problem (MTC) with the objective of selecting the minimum number of sensors required to uniquely identify and localize pipe failure events. First, we summarize a single-level sensing model and discuss an efficient fast greedy approach for solving the MTC problem. Simulation results on benchmark test networks demonstrate the efficacy of the fast greedy algorithm. Second, we develop a multi-level sensing model that captures additional physical features of the disturbance event, such as the time lapsed between the occurrence of disturbance and its detection by the sensor. Our sensor placement approach using MTC extends to the multi-level sensing model and an improved identification performance is obtained via reduced number of sensors (in comparison to single-level sensing model). In particular, we investigate the bi-level sensing model to illustrate the efficacy of employing multi-level sensors for the identification of failure events. Finally, we suggest extensions of our approach for the deployment of heterogeneous sensors in water networks by exploring the trade-off between cost and performance (measured in terms of the identification score of pipe/link failures).

In recent years, cyber security threats have become increasingly dangerous. Hackers have fabricated fake emails to spoof specific users into clicking on malicious attachments or URL links in them. This kind of threat is called a spear-phishing attack. Because spear-phishing attacks use unknown exploits to trigger malicious activities, it is difficult to effectively defend against them. Thus, this study focuses on the challenges faced, and we develop a Cloud-threat Inspection Appliance (CIA) system to defend against spear-phishing threats. With the advantages of hardware-assisted virtualization technology, we use the CIA to develop a transparent hypervisor monitor that conceals the presence of the detection engine in the hypervisor kernel. In addition, the CIA also designs a document pre-filtering algorithm to enhance system performance. By inspecting PDF format structures, the proposed CIA was able to filter 77% of PDF attachments and prevent them from all being sent into the hypervisor monitor for deeper analysis. Finally, we tested CIA in real-world scenarios. The hypervisor monitor was shown to be a better anti-evasion sandbox than commercial ones. During 2014, CIA inspected 780,000 mails in a company with 200 user accounts, and found 65 unknown samples that were not detected by commercial anti-virus software.