Biblio

Two recent proposals by Bernstein and Pornin emphasize the use of deterministic signatures in DSA and its elliptic curve-based variants. Deterministic signatures derive the required ephemeral key value in a deterministic manner from the message to be signed and the secret key instead of using random number generators. The goal is to prevent severe security issues, such as the straight-forward secret key recovery from low quality random numbers. Recent developments have raised skepticism whether e.g. embedded or pervasive devices are able to generate randomness of sufficient quality. The main concerns stem from individual implementations lacking sufficient entropy source and standardized methods for random number generation with suspected back doors. While we support the goal of deterministic signatures, we are concerned about the fact that this has a significant influence on side-channel security of implementations. Specifically, attackers will be able to mount differential side-channel attacks on the additional use of the secret key in a cryptographic hash function to derive the deterministic ephemeral key. Previously, only a simple integer arithmetic function to generate the second signature parameter had to be protected, which is rather straight-forward. Hash functions are significantly more difficult to protect. In this contribution, we systematically explain how deterministic signatures introduce this new side-channel vulnerability.

The pervasive presence of interconnected objects enables new communication paradigms where devices can easily reach each other while interacting within their environment. The so-called Internet of Things (IoT) represents the integration of several computing and communications systems aiming at facilitating the interaction between these devices. Arduino is one of the most popular platforms used to prototype new IoT devices due to its open, flexible and easy-to-use architecture. Ardunio Yun is a dual board microcontroller that supports a Linux distribution and it is currently one of the most versatile and powerful Arduino systems. This feature positions Arduino Yun as a popular platform for developers, but it also introduces unique infection vectors from the security viewpoint. In this work, we present a security analysis of Arduino Yun. We show that Arduino Yun is vulnerable to a number of attacks and we implement a proof of concept capable of exploiting some of them.

Smart environments and security systems require automatic detection of human behaviors including approaching to or departing from an object. Existing human motion detection systems usually require human beings to carry special devices, which limits their applications. In this paper, we present a system called APID to detect arm reaching by analyzing backscatter communication signals from a passive RFID tag on the object. APID does not require human beings to carry any device. The idea is based on the influence of human movements to the vibration of backscattered tag signals. APID is compatible with commodity off-the-shelf devices and the EPCglobal Class-1 Generation-2 protocol. In APID an commercial RFID reader continuously queries tags through emitting RF signals and tags simply respond with their IDs. A USRP monitor passively analyzes the communication signals and reports the approach and departure behaviors. We have implemented the APID system for both single-object and multi-object scenarios in both horizontal and vertical deployment modes. The experimental results show that APID can achieve high detection accuracy.

Sego is a hypervisor-based system that gives strong privacy and integrity guarantees to trusted applications, even when the guest operating system is compromised or hostile. Sego verifies operating system services, like the file system, instead of replacing them. By associating trusted metadata with user data across all system devices, Sego verifies system services more efficiently than previous systems, especially services that depend on data contents. We extensively evaluate Sego's performance on real workloads and implement a kernel fault injector to validate Sego's file system-agnostic crash consistency and recovery protocol.

Mobile devices offer access to our digital lives and thus need to be protected against the risk of unauthorized physical access by applying strong authentication, which in turn adversely affects usability. The actual risk, however, depends on dynamic factors like day and time. In this paper we discuss the idea of using location-based risk assessment in combination with multi-modal biometrics to adjust the level of authentication necessary to the situational risk of unauthorized access.

We develop and evaluate a data hiding method that enables smartphones to encrypt and embed sensitive information into carrier streams of sensor data. Our evaluation considers multiple handsets and a variety of data types, and we demonstrate that our method has a computational cost that allows real-time data hiding on smartphones with negligible distortion of the carrier stream. These characteristics make it suitable for smartphone applications involving privacy-sensitive data such as medical monitoring systems and digital forensics tools.

The ubiquity of portable mobile devices equipped with built-in cameras have led to a transformation in how and when digital images are captured, shared, and archived. Photographs and videos from social gatherings, public events, and even crime scenes are commonplace online. While the spontaneity afforded by these devices have led to new personal and creative outlets, privacy concerns of bystanders (and indeed, in some cases, unwilling subjects) have remained largely unaddressed. We present I-Pic, a trusted software platform that integrates digital capture with user-defined privacy. In I-Pic, users choose alevel of privacy (e.g., image capture allowed or not) based upon social context (e.g., out in public vs. with friends vs. at workplace). Privacy choices of nearby users are advertised via short-range radio, and I-Pic-compliant capture platforms generate edited media to conform to privacy choices of image subjects. I-Pic uses secure multiparty computation to ensure that users' visual features and privacy choices are not revealed publicly, regardless of whether they are the subjects of an image capture. Just as importantly, I-Pic preserves the ease-of-use and spontaneous nature of capture and sharing between trusted users. Our evaluation of I-Pic shows that a practical, energy-efficient system that conforms to the privacy choices of many users within a scene can be built and deployed using current hardware.

This last decade has witnessed a wide adoption of connected mobile devices able to capture the context of their owners from embedded sensors (GPS, Wi-Fi, Bluetooth, accelerometers). The advent of mobile and pervasive computing has enabled rich social and contextual applications, but the use of such technologies raises severe privacy issues and challenges. The privacy threats come from diverse adversaries, ranging from curious service providers and other users of the same service to eavesdroppers and curious applications running on the device. The information that can be collected from mobile device owners includes their locations, their social relationships, and their current activity. All of this, once analyzed and combined together through inference, can be very telling about the users' private lives. In this talk, we will describe privacy threats in mobile and pervasive networks. We will also show how to quantify the privacy of the users of such networks and explain how information on co-location can be taken into account. We will describe the role that privacy enhancing technologies (PETs) can play and describe some of them. We will also explain how to prevent apps from sifting too many personal data under Android. We will conclude by mentioning the privacy and security challenges raised by the quantified self and digital medicine

The prevalent integration of highly intermittent renewable distributed energy resources (DER) into microgrids necessitates the deployment of a microgrid controller. In the absence of the main electric grid setting the network voltage and frequency, the microgrid power and energy management becomes more challenging, accentuating the need for a centralized microgrid controller that, through communication links, ensures smooth operation of the autonomous system. This extensive reliance on information and communication technologies (ICT) creates potential access points and vulnerabilities that may be exploited by cyber-attackers. This paper first presents a typical microgrid configuration operating in islanded mode; the microgrid elements, primary and secondary control functions for power, energy and load management are defined. The information transferred from the central controller to coordinate and dispatch the DERs is provided along with the deployable communication technologies and protocols. The vulnerabilities arising in such microgrids along with the cyber-attacks exploiting them are described. The impact of these attacks on the microgrid controller functions was shown to be dependent on the characteristics, location and target of the cyber-attack, as well as the microgrid configuration and control. A real-time hardware-in-the loop (HIL) testing platform, which emulates a microgrid featuring renewable DERs, an energy storage system (ESS), a diesel generator and controllable loads was used as the case study in order to demonstrate the impact of various cyber-attacks.

There is growing evidence that spear phishing campaigns are increasingly pervasive, sophisticated, and remain the starting points of more advanced attacks. Current campaign identification and attribution process heavily relies on manual efforts and is inefficient in gathering intelligence in a timely manner. It is ideal that we can automatically attribute spear phishing emails to known campaigns and achieve early detection of new campaigns using limited labelled emails as the seeds. In this paper, we introduce four categories of email profiling features that capture various characteristics of spear phishing emails. Building on these features, we implement and evaluate an affinity graph based semi-supervised learning model for campaign attribution and detection. We demonstrate that our system, using only 25 labelled emails, achieves 0.9 F1 score with a 0.01 false positive rate in known campaign attribution, and is able to detect previously unknown spear phishing campaigns, achieving 100% 'darkmoon', over 97% of 'samkams' and 91% of 'bisrala' campaign detection using 246 labelled emails in our experiments.

Detecting early trends indicating cognitive decline can allow older adults to better manage their health, but current assessments present barriers precluding the use of such continuous monitoring by consumers. To explore the effects of cognitive status on computer interaction patterns, the authors collected typed text samples from older adults with and without pre-mild cognitive impairment (PreMCI) and constructed statistical models from keystroke and linguistic features for differentiating between the two groups. Using both feature sets, they obtained a 77.1 percent correct classification rate with 70.6 percent sensitivity, 83.3 percent specificity, and a 0.808 area under curve (AUC). These results are in line with current assessments for MC–a more advanced disease–but using an unobtrusive method. This research contributes a combination of features for text and keystroke analysis and enhances understanding of how clinicians or older adults themselves might monitor for PreMCI through patterns in typed text. It has implications for embedded systems that can enable healthcare providers and consumers to proactively and continuously monitor changes in cognitive function.

Pervasive Computing is one of the latest and more advanced paradigms currently available in the computers arena. Its ability to provide the distribution of computational services within environments where people live, work or socialize leads to make issues such as privacy, trust and identity more challenging compared to traditional computing environments. In this work we review these general issues and propose a Pervasive Computing architecture based on a simple but effective trust model that is better able to cope with them. The proposed architecture combines some Artificial Intelligence techniques to achieve close resemblance with human-like decision making. Accordingly, Apriori algorithm is first used in order to extract the behavioral patterns adopted from the users during their network interactions. Naïve Bayes classifier is then used for final decision making expressed in term of probability of user trustworthiness. To validate our approach we applied it to some typical ubiquitous computing scenarios. The obtained results demonstrated the usefulness of such approach and the competitiveness against other existing ones.

The performance of indirect trust computation models (based on recommendations) can be easily compromised due to the subjective and social-based prejudice of the provided recommendations. Eradicating the influence of such recommendation remains an important and challenging issue in indirect trust computation models. An effective model for indirect trust computation is proposed which is capable of identifying dishonest recommendations. Dishonest recommendations are identified by using deviation based detecting technique. The concept of measuring the credibility of recommendation (rather than credibility of recommender) using fuzzy inference engine is also proposed to determine the influence of each honest recommendation. The proposed model has been compared with other existing evolutionary recommendation models in this field, and it is shown that the model is more accurate in measuring the trustworthiness of unknown entity.