TinyTate: Identity-Based Encryption for Sensor Networks

In spite of several years of intense research, the area of security and cryptography in Wireless Sensor Networks (WSNs) still has a number of open problems. On the other hand, the advent of Identity-Based Encryption (IBE) has enabled a wide range of new cryptographic solutions. In this work, we argue that IBE is ideal for WSNs and vice versa. We discuss the synergy between the systems, describe how WSNs can take advantage of IBE, and present results for computation of the Tate pairing over resource constrained nodes

A Practical Second-Order Fault Attack against a Real-World Pairing Implementation

Several fault attacks against pairing-based cryptography have been described theoretically in recent years. Interestingly, none of these have been practically evaluated. We accomplished this task and prove that fault attacks against pairing-based cryptography are indeed possible and are even practical — thus posing a serious threat. Moreover, we successfully conducted a second-order fault attack against an open source implementation of the eta pairing on an AVR XMEGA A1. We injected the first fault into the computation of the Miller Algorithm and applied the second fault to skip the final exponentiation completely. We introduce a low-cost setup that allowed us to generate multiple independent faults in one computation. The setup implements these faults by clock glitches which induce instruction skips. With this setup we conducted the first practical fault attack against a complete pairing computation

TinyPBC: Pairings for Authenticated Identity-Based Non-Interactive Key Distribution in Sensor Networks

Key distribution in Wireless Sensor Networks (WSNs) is challenging. Symmetric cryptosystems can perform it efficiently, but they often do not provide a perfect trade-off between resilience and storage. Further, even though conventional public key and elliptic curve cryptosystem are computationally feasible on sensor nodes, protocols based on them are not. They require exchange and storage of large keys and certificates, which is expensive. Using Pairing-based Cryptography (PBC) protocols, conversely, parties can agree on keys without any interaction. In this work, we (i) show how security in WSNs can be bootstrapped using an authenticated identity-based non-interactive protocol and (ii) present TinyPBC, to our knowledge, the most efficient implementation of PBC primitives for an 8-bit processor. TinyPBC is an open source code able to compute pairings as well as binary multiplication in about 5.5s and 4019.46$\mu$s, respectively, on the ATmega128L 7.3828-MHz/4KB SRAM/128KB ROM processor -- the MICA2 and MICAZ node processor

Fighting Sinkhole Attacks in Tree-based Routing Topologies

This work focuses on: (1) understanding the impact of sinkhole attacks on tree-based routing topologies in Wireless Sensor Networks (WSNs), and (2) investigating cryptography-based strategies to limit network degradation caused by these attacks. This work is particularly important as WSN protocols that construct a fixed routing topology may be significantly affected by malicious attacks. Furthermore, considering networks deployed in a difficult to access geographical region, building up resilience against such attacks rather than detection is expected to be more beneficial. We thus first provide a simulation study on the impact of malicious attacks based on a diverse set of parameters, such as the network scale and the position and number of malicious nodes. Based on this study, we propose a single but very representative metric for describing this impact. Second, we present the novel design and evaluation of two \emph{simple and resilient} topology-based reconfiguration protocols that broadcasts cryptographic values. The results of our simulation study show that our reconfiguration protocols are practical and effective in improving resilience against sinkhole attacks, even in the presence of some collusion

A sinkhole resilient protocol for wireless sensor networks: Performance and security analysis

International audienceThis work focuses on: (1) understanding the impact of selective forwarding attacks on tree-based routing topologies in wireless sensor networks (WSNs), and (2) investigating cryptography-based strategies to limit network degradation caused by sinkhole attacks. The main motivation of our research stems from the following observations. First, WSN protocols that construct a fixed routing topology may be significantly affected by malicious attacks. Second, considering networks deployed in a difficult to access geographical region, building up resilience against such attacks rather than detection is expected to be more beneficial. We thus first provide a simulation study on the impact of malicious attacks based on a diverse set of parameters, such as the network scale and the position and number of malicious nodes. Based on this study, we propose a single but very representative metric for describing this impact. Second, we present the novel design and evaluation of two simple and resilient topology-based reconfiguration protocols that broadcast cryptographic values. The results of our simulation study together with a detailed analysis of the cryptographic overhead (communication, memory, and computational costs) show that our reconfiguration protocols are practical and effective in improving resilience against sinkhole attacks, even in the presence of collusion

Cryptographic key distribuition in sensor networks

Orientador: Ricardo DahabTese (doutorado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: Redes de Sensores Sem Fio (RSSFs) são compostas em sua maioria por pequenos nós sensores dotados de recursos extremamente limitados. Estes, por sua vez, se comunicam com o mundo externo através de nós poderosos chamados de sorvedouros ou estações rádio base. RSSFs são empregadas com o objetivo de monitorar regiões, oferecendo dados sobre a área monitorada para o resto do sistema. Tais redes podem ser utilizadas para diferentes aplicações, tais como operações de resgate em áreas de conflito/desastre, espionagem industrial e detecção de exploração ilegal de recursos naturais. Em RSSFs existem aplicações críticas nas quais propriedades de segurança são de vital importância. Segurança, por sua vez, é comumente alavancada através de esquemas de distribuição de chaves. A maioria dos padrões de distribuição de chaves presentes na literatura, todavia, não são apropriados para RSSFs: métodos baseados em esquemas de chave pública convencionais, devido aos seus requisitos de processamento e banda; chaves de grupo, em função das suas vulnerabilidades de segurança; e chaves par-a-par (pairwise), por causa da baixa escalabilidade. Um outro dado é que há uma vasta gama de arquiteturas propostas para RSSFs e que uma mesma técnica de distribuição de chaves pode ser a melhor para uma, mas não para outra, visto que diferentes arquiteturas de rede exibem padrões de comunicação distintos. Em outras palavras, não existe uma panacéia, e mecanismos de distribuição de chaves para RSSFs devem, portanto, levar em consideração as idiossincrasias das arquiteturas para as quais são projetadas. Tudo isso torna extremamente difícil e desafiadora a tarefa de dotar RSSFs de segurança. O objetivo deste trabalho foi propor soluções de distribuição de chaves que, concomitantemente, (i) fossem compatíveis com os recursos dos sensores e (ii) considerassem as particularidades das arquiteturas para as quais são propostas. Como será mostrado ao longo desta tese, iniciamos nosso trabalho com soluções personalizadas para certas arquiteturas de RSSFs e evoluímos para soluções flexíveis em que a segurança é alavancada de forma não interativa - o que é ideal para este tipo de rede. Até onde sabemos, nosso trabalho é pioneiro em soluções de segurança para RSSFs hierárquicas e em distribuição de chaves de forma autenticada e não interativa, usando Criptografia Baseada em Identidade, neste tipo de rede.Abstract: Wireless sensor networks (WSNs) are ad hoc networks comprised mainly of small sensor nodes with limited resources and one or more base stations, which are much more powerful laptop-class nodes that connect the sensor nodes to the rest of the world. WSNs are used for monitoring purposes, providing information about the area being monitored to the rest of the system. Application areas range from battlefield reconnaissance and emergency rescue operations to surveillance and environmental protection. There are also critical WSN applications in which security properties are of paramount importance. Security, in turn, is frequently bootstrapped through key distribution schemes. Most of the key distribution techniques, however, are ill-suited to WSNs: public key based distribution, because of its processing and bandwidth requirements; global keying, because of its security vulnerabilities; complete pairwise keying, because of its memory requirements. It is worth noting, however, that a large number of WSN architectures have been proposed and a key distribution solution that is well suited to one architecture is likely not to be the best for another, as different network architectures exhibit different communication patterns. In other words, there is no panacea and the design of a key distribution scheme must therefore be driven by the peculiarities of the WSN architecture in question. This all makes extremely hard and challenging the objective of securing WSNs. In this work, we aimed at proposing key distribution schemes that are both (i) lightweight and (ii) able to fulfill architecture-specific needs. As it will be shown throughout this thesis, we began our work with customized solutions for certain types of WSNs and then, subsequently, turned our attention to more flexible solutions, where security is bootstrapped in a non-interactive way through the use of Identity-Based Cryptography.DoutoradoTeoria da ComputaçãoDoutor em Ciência da Computaçã

The effect of time dimension and network dynamics on key distribution in wireless sensor networks

The majority of studies on security in resource limited wireless sensor networks (WSN) focus on finding an efficient balance among energy consumption, computational speed and memory usage. Besides these resources, time, network dynamics (e.g. routing), and implementation and integration issues of the security solutions are relatively immature aspects that can be considered in system design and performance evaluations. In the first part of this thesis, we develop and analyze different implementation options of a Random Key Predistribution scheme in a real network simulation environment. Implementation options include Proactive Key Establishment and Reactive Key Establishment. In Proactive Key Establishment, pairwise keys are established at the beginning, prior to start of application. In Reactive Key Establishment, keys are established only whenever needed by the application during its execution. In literature the latter is known to preserve energy since it reduces useless key establishments; however, it also introduces delay in application traffic. We implement the reactive key establishment in such a way that key establishment traffic and energy consumption are reduced. As a result our reactive key establishment implementation has similar throughput performance with proactive scenarios despite the longer lifetime of reactive scenario. We also simulate an attack scenario and measure different metrics including a novel one. This new metric, the packet compromise ratio, reflects the harm caused by the adversary in a more realistic way. In our simulations, we show that packet compromise ratios are very high as compared to link compromise ratios for a long period. However, when the majority of nodes die, link compromise ratios exceed packet compromise ratios. This is an indication to the fact that link compromise ratios seem high even though there is no high amount of traffic in network to be compromised by adversary. Due to the results showing that classical key distribution schemes in WSNs have actually low resiliency, in the second part of this thesis, we propose new deployment models that improve resiliency. In a recent study by Castelluccia and Spognardi, the time dimension is used to lower the ratio of compromised links, thus, improving resiliency in key distribution in WSNs. This is achieved by making the old and possibly compromised keys useful only for a limited amount of time. In this way, the effect of compromised keys diminishes in time, so the WSN selfheals. We further manipulate the time dimension and propose a deployment model that speeds up the resiliency improvement process with a tradeo between connectivity and resiliency. In our method, self healing speeds up by introducing nodes that belong to future generations in the time scale. In this way, the duration that the adversary can make use of compromised keys becomes smaller

Security Properties of Information-centric Networks

The IP network was built decades ago, and with today s use of Internet, a new network layer protocol is much needed. Named Data Networking (NDN) is a proposal for content-centric discovery and routing. Yet, the public key infrastructure issue has not been solved in NDN. Identity-based cryptography (IBC) seems to be applicable to wireless sensor networks, and even more applicable when deployed over NDN. In this paper I will explain the NDN architecture and the basics of IBC. Further, I will model and implement a trust model in a thought sensor network using IBC, running over NDN. Implementing and testing my proposal verifies the relevancy of IBC over wireless sensor network running over NDN, and the usability of developing applications over NDN. I formally and informally prove the security in the protocols suggested for device registration and data pull under deployment in the application

Cryptographic Key Distribution In Wireless Sensor Networks Using Bilinear Pairings

It is envisaged that the use of cheap and tiny wireless sensors will soon bring a third wave of evolution in computing systems. Billions of wireless senor nodes will provide a bridge between information systems and the physical world. Wireless nodes deployed around the globe will monitor the surrounding environment as well as gather information about the people therein. It is clear that this revolution will put security solutions to a great test. Wireless Sensor Networks (WSNs) are a challenging environment for applying security services. They differ in many aspects from traditional fixed networks, and standard cryptographic solutions cannot be used in this application space. Despite many research efforts, key distribution in WSNs still remains an open problem. Many of the proposed schemes suffer from high communication overhead and storage costs, low scalability and poor resilience against different types of attacks. The exclusive usage of simple and energy efficient symmetric cryptography primitives does not solve the security problem. On the other hand a full public key infrastructure which uses asymmetric techniques, digital signatures and certificate authorities seems to be far too complex for a constrained WSN environment. This thesis investigates a new approach to WSN security which addresses many of the shortcomings of existing mechanisms. It presents a detailed description on how to provide practical Public Key Cryptography solutions for wireless sensor networks. The contributions to the state-of-the-art are added on all levels of development beginning with the basic arithmetic operations and finishing with complete security protocols. This work includes a survey of different key distribution protocols that have been developed for WSNs, with an evaluation of their limitations. It also proposes Identity- Based Cryptography (IBC) as an ideal technique for key distribution in sensor networks. It presents the first in-depth study of the application and implementation of Pairing- Based Cryptography (PBC) to WSNs. This is followed by a presentation of the state of the art on the software implementation of Elliptic Curve Cryptography (ECC) on typical WSNplatforms. New optimized algorithms for performing multiprecision multiplication on a broad range of low-end CPUs are introduced as well. Three novel protocols for key distribution are proposed in this thesis. Two of these are intended for non-interactive key exchange in flat and clustered networks respectively. A third key distribution protocol uses Identity-Based Encryption (IBE) to secure communication within a heterogeneous sensor network. This thesis includes also a comprehensive security evaluation that shows that proposed schemes are resistant to various attacks that are specific to WSNs. This work shows that by using the newest achievements in cryptography like pairings and IBC it is possible to deliver affordable public-key cryptographic solutions and to apply a sufficient level of security for the most demanding WSN applications