We demonstrate attribute-based authentication and access control schemes tailored to resource-constrained devices typical of IoT home environments. The demo shows how IoT devices would be managed and controlled in such scenario. The underlying cryptographic scheme relies on an Attribute-Based Cryptosystem (ABC) to cryptographically implement an authenticated Attribute-Based Access Control (ABAC) mechanism.

In this demo, we will showcase FLAT, a federated identity model tailored to IoT. FLAT's authentication is lightweight because it uses only symmetric cryptosystems on the IoT client side and implicit certificates between the Identity and Service Providers. We show how FLAT can be used to increase security and privacy in automatic toll gate payment applications.

Decades went by since Mark Weiser published his influential work on how a computer of the 21st century would look like. Over the years, some of the UbiComp features presented in that paper have been gradually adopted by industry players in the technology market. While this technological evolution resulted in many benefits to our society, it has also posed, along the way, countless challenges that we have yet to surpass. In this paper, we address major challenges from two areas that most afflict the UbiComp revolution: security and privacy. We examine open problems on software protection, long-term security, cryptography engineering, and privacy implications. We also point out promising directions towards the solutions of those problems. We claim that if we get all this right, we will turn the science fiction of UbiComp into science fact.

The growing importance of Internet of Things (IoT) calls for tools able to provide users with secure systems. Traditional approaches to analyze distributed systems are not expressive enough to address this challenge. As a solution, we present a framework to analyze networked embedded systems. Our key insight is to look at a distributed system as a single body, and not as separate programs that exchange messages. We then can crosscheck information inferred from different nodes. To construct this global view of a distributed system, we introduce a novel algorithm that discovers inter-program links efficiently. Such links lets us build an inter-program view, a knowledge that we can thus forward to a traditional static analysis tool. We prove that our algorithm always terminates and that it correctly models the semantics of a distributed system. We have implemented our solution on top of the LLVM compiler, and have used it to secure six ContikiOS applications against buffer overflow attacks. Our solution produces code that is as safe as code secured by more traditional analyses; however, our binaries are on average 18% more energy-efficient.

It is paramount to ensure secure and trustworthy operations in Cyber-Physical Systems (CPSs), guaranteeing the integrity of sensing data, enabling access control, and safeguarding system-level operations. In this paper, we address trustworthy operations of next generation CPSs. Our idea is inspired by a trustworthy computing framework known as Proof-Carrying Code, in which foreign executables carry a model to prove that they have not been tampered with and they function as expected. In our context, we leverage the physical world--a channel that encapsulates properties impossible to tamper with remotely, such as proximity and causality--to create a challenge-response function. We call it Proof-Carrying Sensing and use it to help authenticate devices, collected data, and locations. A unique advantage of this approach, vis-à-vis traditional multi-factor or out-of-band authentication mechanisms, is that authentication proofs are embedded in sensor data and can be continuously validated over time and space without resorting to complicated cryptographic algorithms. This, in turn, makes it fit particularly well to CPSs where mobility and resource constraints are common.

A Buffer Overflow (BOF) continues to be among the top open doors to worms and malware. Earlier in 2014, the security world was taken by surprise when researches unveiled a BOF in OpenSSL. Languages like C and C++, widely used for system development and for a large variety of applications, do not provide native Array-Bound Checks (ABC). A myriad of proposals endeavor memory protection for such languages by employing both software- and hardware-based solutions. Due to numerous reasons, none of them have yet reached the mainstream. In this work we propose a novel approach to achieve an array bound-check and a memory access (when allowed) within a single instruction. We discuss how it can be implemented on variable-length ISAs and provide a reference implementation. Our results indicate that our solution can run programs 1,79× faster than the software-based approach.

Alias analysis is one of the most fundamental techniques that compilers use to optimize languages with pointers. However, in spite of all the attention that this topic has received, the current state-of-the-art approaches inside compilers still face challenges regarding precision and speed. In particular, pointer arithmetic, a key feature in C and C++, is yet to be handled satisfactorily. This paper presents a new alias analysis algorithm to solve this problem. The key insight of our approach is to combine alias analysis with symbolic range analysis. This combination lets us disambiguate fields within arrays and structs, effectively achieving more precision than traditional algorithms. To validate our technique, we have implemented it on top of the LLVM compiler. Tests on a vast suite of benchmarks show that we can disambiguate several kinds of C idioms that current state-of-the-art analyses cannot deal with. In particular, we can disambiguate 1.35x more queries than the alias analysis currently available in LLVM. Furthermore, our analysis is very fast: we can go over one million assembly instructions in 10 seconds.

The growing importance of smart devices calls for effective user authentication mechanisms. We argue that state-of-the-art authentication mechanisms are either vulnerable to known attacks or do not meet usability needs. To address this problem we designed NomadiKey, a user-to-device authentication mechanism based on nomadic keyboard keys. NomadiKey increases security level by placing keys at different screen coordinates each time NomadiKey is activated. Besides, NomadiKey preserves usability by maintaining the traditional relative position of keys. We compare NomadiKey with other user authentication mechanisms under different attacks using statistical models and simulation. We also evaluate NomadiKey's usability with 18 users. Our results show that NomadiKey increases security compared to widely-deployed PIN authentication with limited impact on authentication times.

The consumer electronics industry is witnessing a surge in Internet of Things (IoT) devices, ranging from mundane artifacts to complex biosensors connected across disparate networks. As the demand for IoT devices grows, the need for stronger authentication and access control mechanisms is greater than ever. Legacy authentication and access control mechanisms do not meet the growing needs of IoT. In particular, there is a dire need for a holistic authentication mechanism throughout the IoT device life-cycle, namely from the manufacturing to the retirement of the device. As a plausible solution, we present Authentication of Things (AoT), a suite of protocols that incorporate authentication and access control during the entire IoT device life span. Primarily, AoT relies on Identity- and Attribute-Based Cryptography to cryptographically enforce Attribute-Based Access Control (ABAC). Additionally, AoT facilitates secure (in terms of stronger authentication) wireless interoperability of new and guest devices in a seamless manner. To validate our solution, we have developed AoT for Android smartphones like the LG G4 and evaluated all the cryptographic primitives over more constrained devices like the Intel Edison and the Arduino Due. This included the implementation of an Attribute-Based Signature (ABS) scheme. Our results indicate AoT ranges from highly efficient on resource-rich devices to affordable on resource-constrained IoT-like devices. Typically, an ABS generation takes around 27 ms on the LG G4, 282 ms on the Intel Edison, and 1.5 s on the Arduino Due.

We present a discriminative key pose-based approach for moves recognition and segmentation of training sequences for high performance sports. Compared to daily human gestures, moves in high performance sports are faster and have low inter-class variability, which produce noisy features and ambiguity. Our approach combines a robust filtering strategy to select frames composed of discriminative poses (key poses) and the discriminative Latent-Dynamic Conditional Random Fields (LDCRF) model to predict a label for each frame from the training sequence. We evaluate our approach on unsegmented sequences of Taekwondo training. Experimental results indicate that our methodology outperforms the Decision Forests method in terms of efficiency and accuracy. Our average recognition rate was equal to 74.72% while Decision Forests achieves 58.29%. The experiments also show that our approach was able to recognize and segment high speed moves like roundhouse kicks, which can reach peak linear speeds up to 26 m/s.

The Internet of Things (IoT) is increasingly more relevant. This growing importance calls for tools able to provide users with correct, reliable and secure systems. In this paper, we claim that traditional approaches to analyze distributed systems are not expressive enough to address this challenge. As a solution to this problem, we present SIoT, a framework to analyze networked systems. SIoT's key insight is to look at a distributed system as a single body, and not as separate programs that exchange messages. By doing so, we can crosscheck information inferred from different nodes. This crosschecking increases the precision of traditional static analyses. To construct this global view of a distributed system we introduce a novel algorithm that discovers inter-program links efficiently. Such links lets us build a holistic view of the entire network, a knowledge that we can thus forward to a traditional tool. We prove that our algorithm always terminates and that it correctly models the semantics of a distributed system. To validate our solution, we have implemented SIoT on top of the LLVM compiler, and have used one instance of it to secure 6 ContikiOS applications against buffer overflow attacks. This instance of SIoT produces code that is as safe as code secured by more traditional analyses; however, our binaries are on average 18% more energy-efficient.

The C programming language does not prevent out-of-bounds memory accesses. There exist several techniques to secure C programs; however, these methods tend to slow down these programs substantially, because they populate the binary code with runtime checks. To deal with this problem, we have designed and tested two static analyses - symbolic region and range analysis - which we combine to remove the majority of these guards. In addition to the analyses themselves, we bring two other contributions. First, we describe live range splitting strategies that improve the efficiency and the precision of our analyses. Secondly, we show how to deal with integer overflows, a phenomenon that can compromise the correctness of static algorithms that validate memory accesses. We validate our claims by incorporating our findings into AddressSanitizer. We generate SPEC CINT 2006 code that is 17% faster and 9% more energy efficient than the code produced originally by this tool. Furthermore, our approach is 50% more effective than Pentagons, a state-of-the-art analysis to sanitize memory accesses.

Wireless Sensor Networks (WSNs) are comprised mainly of resource-constrained sensor nodes that can be used to monitor areas of interest. In sensor networks, replacement of node batteries is usually infeasible and power consumption must be minimal to increase node lifetime. A large fraction of power consumption is controlled by the MAC layer, which orchestrates access to the wireless medium trading-off power consumption and throughput. Unfortunately, this orchestration requires exchange of additional data and itself ends up consuming energy. In this work we design a novel approach that does not require extra data to be exchanged. More precisely, we present ID-MAC: an identity-based MAC protocol for WSNs. In ID-MAC, sensor nodes compute when they should wake up in order to transmit and receive frames from their neighbors without exchanging coordination messages. Our evaluation shows that, by eliminating coordination messages, ID-MAC saves energy and prolongs the network's operating lifespan.

Under-Water Wireless Sensor Networks (UWSNs) are a particular class of Wireless Sensor Networks (WSNs) in which sensors are located, as the name suggests, underwater. Applications of UWSNs range from oceanographic data collection to disaster prevention. UWSNs are vulnerable to attacks and because of their idiosyncrasies, security solutions for ground WSNs might not be applicable underwater. As a result, there is a need for mechanisms exclusively tailored to underwater environments. In this work we address the problem of authentication in UWSNs. We evaluate energy costs for different digital signature schemes for end-to-end authentication and discuss the tradeoffs involved in a number of scenarios. Our results show that schemes that perform well in ground WSN do not necessarily do well in UWSNs; and shed light on characteristics of a digital signature scheme that make them particularly suited to underwater networks.

In this paper, two Medium Access Control (MAC) protocols exclusively tailored to WSNs over RoF (RWSNs) namely SPP-MAC (Scheduled Priority Polling Medium Access Control) (polling-based) and HMARS (Hybrid Medium Access Control for Hybrid Radio-over-Fiber Wireless Sensor Network Architecture) (hybrid-based) are proposed. They deal with the main problems in RWSNs i.e. the delay imposed by optical fiber and the existence of two collision domains: the wireless and the fiber optical links. The performance of these two protocols evince their effectiveness for the connection of WSNs by RoF links.

Recent works have shown the usefulness of network and application layer protocols that connect low-power sensor nodes directly to multiple applications and users on the Internet. We propose a security solution for this scenario. While previous works have provided security support for various communication patterns in sensor networks, such as among nodes, from nodes to a base station, and from users to nodes, the security of communication from sensor nodes to multiple users has not been sufficiently addressed. Specifically, we explore this design space and develop a security solution, named Secure Tiny Web Service, for efficient authentication of data sent by a resource-constrained sensor node to multiple users, using digital signatures. We investigate the resource overheads in communication and computation of four suitable signature schemes—the Elliptic Curve Digital Signature Algorithm, the (elliptic curve) Schnorr signature, and the Boneh–Lynn–Shacham and Zhang–Safavi-Naini–Susilo short signature schemes. We implement these schemes on two popular sensor node architectures (based on AVR ATmega128L and MSP430 processors with 802.15.4 radios) and experimentally characterize relevant trade-offs.

After a few years of intense research, wireless sensor networks (WSNs) still demand new secure and cryptographic schemes. On the other hand, the advent of cryptography from pairings has enabled a wide range of novel cryptosystems. In this work we present TinyTate, the first known implementation of pairings for sensor nodes based on the 8-bit/7.3828-MHz ATmega128L microcontroller (e.g., MICA2 and MICAz motes). We then conclude that cryptography from pairings is indeed viable in resource-constrained nodes.

Wireless sensor networks are ad hoc networks comprised mainly of small sensor nodes with limited resources and one or more base stations, which are much more powerful laptopclass nodes that connect the sensor nodes to the rest of the world. The advent of this tecnology over the last decade enables largescale deployment of such sensors. On the other hand, this poses the challenging of how the great amount of information generated by these sensor networks will be handled at the base station. In this paper, we propose a network processor architecture tailored specifically to handling information at sensor network base stations. Our approach optimize information processing by implementing tasks in hardware. We show that the novel architecture is one order of magnitude faster than an architecture based on traditional RISC processor.

Clustered sensor networks have been shown to increase system throughput, decrease system delay, and save energy. While those with rotating cluster heads, such as LEACH, have also advantages in terms of security, the dynamic nature of their communication makes most existing security solutions inadequate for them. In this paper, we show how random key predistribution, widely studied in the context of flat networks, can be used to secure communication in hierarchical (cluster-based) protocols such as LEACH. To our knowledge, it is the first work that investigates random key predistribution as applied to hierarchical WSNs

Wireless sensor networks (WSNs) are ad hoc networks comprised mainly of small sensor nodes with limited resources, and can be used to monitor areas of interest. In this paper, we propose a solution for securing heterogeneous hierarchical WSNs with an arbitrary number of levels. Our solution relies exclusively on symmetric key schemes, is highly distributed, and takes into account node interaction patterns that are specific to clustered WSNs.

Both mobile ad hoc networks (MANETs) and peer-to-peer (P2P) networks are decentralized and self-organizing networks with dynamic topology and are responsible for routing queries in a distributed environment. Because MANETs are composed of resource-constrained devices susceptible to faults, whereas P2P networks are fault-tolerant, P2P networks are the ideal data sharing system for MANETs. We have conducted an evaluation of two approaches for P2P content discovery running over a MANET. The first, based on unstructured P2P networks, relies on controlled flooding, while the second, based on structured P2P networks, uses distributed indexing to optimize searches. We use simulations to evaluate the effect of network size, mobility, channel error rates, network workload, and application dynamics in the performance of P2P protocols over MANETs. Results show that unstructured protocols are the most resilient, although at higher energy and delay costs. Structured protocols, conversely, consume less energy and are more appropriate for MANETs where topology is mostly static.

Wireless Sensor Networks (WSNs) have emerged as a new monitoring and control solution for a variety of applications. Although the behavior of a WSN is characterized by the type of its application, a common element exist: faults are a normal fact, not isolated events as in traditional networks. Thus, in order to guarantee the network quality of service it is essential for the WSN to be able to detect failures and perform something akin to healing, recovering from events that might cause some of its parts to malfunction. In this work we propose and evaluate a failure detection scheme using a management architecture for WSNs, called MANNA. We take a deep look at its fault management capabilities supposing the existence of an event-driven WSN. This is a challenging and attractive kind of WSN and we show how the use of automatic management services defined by MANNA can provide self-configuration, self-diagnostic, and self-healing (some of the self-managing capabilities). We also show that the management solution promote the resources productivity without incurring a high cost to the network.

Mobile ad hoc networks (MANETs) and peer-to-peer (P2P) applications are emerging technologies based on the same paradigm: the peer-to-peer paradigm. Motivated, respectively, by the necessity of executing applications in environments with no previous infra-structure and the demand for applications that share, in a satisfying manner, files through the Internet, MANETs and P2P applications have brought onto themselves some interest from the community. As a characteristic of the distributed model which they follow, such technologies face a difficult task of routing requests in a decentralized environment. In this paper, we conducted a detailed study of a Gnutella-like application running over a mobile ad-hoc network where three different protocols were considered. The results show that each of the protocols analyzed performed well in some scenarios for some metrics yet had drawbacks in others.