Billions of devices are being connected to the Internet creating the Internet of Things (IoT). The IoT not only requires strong security, like current Internet applications, but also efficient operation. The recently introduced HIMMO scheme enables lightweight and collusion-resistant identity-based key sharing in a non-interactive way, so that any pair of Internet-connected devices can securely communicate. This paper firstly reviews the HIMMO scheme and introduces two extensions that e.g. enable implicit credential verification without the need of traditional digital certificates. Then, we show how HIMMO can be efficiently implemented even in resource-constrained devices, enabling combined key agreement and credential verification more efficiently than using ECDH-ECDSA. We further explain how HIMMO helps to secure the Internet and IoT by introducing the DTLS-HIMMO operation mode. DTLS, the datagram version of TLS, is becoming the standard security protocol in the IoT, although it is very frequently discussed that it does not offer the right performance for IoT scenarios. Our design, implementation, and evaluation show that DTLS-HIMMO operation mode achieves the security properties of the DTLS-Certificate security suite while exhibiting the overhead of symmetric-key primitives without requiring changes in the DTLS standard.

We consider a two polynomials analogue of the polynomial interpolation problem. Namely, we consider the Mixing Modular Operations (MMO) problem of recovering two polynomials f ∈ Zp[x] and g ∈ Zq[x] of known degree, where p and q are two (un)known positive integers, from the values of f(t) mod p+g(t) mod q at polynomially many points t ∈ Z. We show that if p and q are known, the MMO problem can be reduced to computing a close vector in a lattice with respect to the infinity norm. Using the Gaussian heuristic we also implemented in the SAGE system a polynomial-time algorithm. If p and q are kept secret, we do not know how to solve this problem. This problem is motivated by several potential cryptographic applications.

ABSTRACT The Internet of Things paradigm envisions the pervasive interconnection and cooperation of smart things over the current and future Internet infrastructure. The Internet of Things is, thus, the evolution of the Internet to cover the real world, enabling many new services that will improve people's everyday lives, spawn new businesses, and make buildings, cities, and transport smarter. Smart things allow indeed for ubiquitous data collection or tracking, but these useful features are also examples of privacy threats that are already now limiting the success of the Internet of Things vision when not implemented correctly. These threats involve new challenges such as the pervasive privacy‐aware management of personal data or methods to control or avoid ubiquitous tracking and profiling. This paper analyzes the privacy issues in the Internet of Things in detail. To this end, we first discuss the evolving features and trends in the Internet of Things with the goal of scrutinizing their privacy implications. Second, we classify and examine privacy threats in this new setting, pointing out the challenges that need to be overcome to ensure that the Internet of Things becomes a reality. Copyright © 2013 John Wiley & Sons, Ltd.

The IP-based Internet of Things (IoT) refers to the pervasive interaction of smart devices and people enabling new applications by means of new IP protocols such as 6LoWPAN and CoAP. Security is a must, and for that we need a secure architecture in which all device interactions are protected, from joining an IoT network to the secure management of keying materials. However, this is challenging because existing IP security protocols do not offer all required functionalities and typical Internet solutions do not lead to the best performance.

The IP-based Internet of Things refers to the interconnection of smart devices in a Low-power and Lossy Network (LLN) with the Internet by means of protocols such as 6LoWPAN or CoAP. The mechanisms to protect the LLN from attacks from the Internet and provisioning of an end-to-end (E2E) secure connection are key requirements for functionalities ranging from network access to software updates. Interconnecting such resource constrained devices with high-performance machines requires new security mechanisms that cannot be covered by already known solutions. This paper describes attacks at transport layer against the LLN launched from the Internet. It also introduces approaches to ensure E2E security between two devices located in homogeneous networks using either HTTP/TLS or CoAP/DTLS by proposing a mapping between TLS and DTLS.

ABSTRACT Ubiquitous 24/7 health monitoring systems based on wireless medical sensors are going to play a key role for pervasive e‐health applications. These systems allow care givers to early detect and act on signs of patients' clinical deterioration improving quality of care in a reliable unobtrusive and cost effective way. Ensuring the privacy and security of the exchanged information is challenging in pervasive e‐health environments due to the resource constraints of tiny wireless medical sensors and operational requirements such as user mobility, strict latency needs, or the multitude of parties involved in the system. This paper describes a comprehensive and practical security framework for these pervasive health monitoring systems. We distinguish three layers addressing the specific security needs at the patient area network, medical sensor network, and back‐end levels. Thereby our architecture accommodates the healthcare institution‐centric approach predominant today while making provisions for the more patient‐centric vision of pervasive e‐health environments. The tailored security mechanisms for each individual layer as well as their interworking are presented and evaluated in detail. The analysis shows that our proposed security framework allows the deployment of wireless medical sensor networks in a very efficient way. Copyright © 2010 John Wiley & Sons, Ltd.

Fair node and network operation is a key to ensure the correct system operation. The problem arises when some nodes become compromised or faulty endangering the overall system. This is especially challenging in sensor networks because they are often deployed in hostile environments and have to endure both passive and active attacks. Therefore, a node should only communicate with trusted nodes, while non-trusted nodes should be removed from the system to prevent them from further disrupting its normal operation. To address such threats, we introduce the Efficient Cooperative Security (ECoSec) - a distributed and adaptive protocol that allows a network to control the admission and revocation of nodes in a cooperative and democratic way during two voting rounds. Whereas the contributions of the protocol to the family of cooperative security protocols are two fold. First, it introduces the use of polynomial-based votes showing that its operation, and in general, operation of cooperative security protocols, can endure up to 33% of misbehaving nodes. Second, the protocol applies correlated keying material structures to verify the node admission and node revocation voting procedures reducing the overall communication overhead.

Medical sensor networks allow for pervasive health monitoring of users in hospitals, at home, or on the way. The privacy and confidentiality of medical data need to be guaranteed at any moment to make sure that unauthorized parties cannot retrieve confidential information. This is a great challenge due to two main reasons. First, wireless sensors are resource-constrained devices that limit the applicability of traditional solutions. Second, the access control system must be context-aware and adapt its security settings to ensure the users' safety during, e.g., medical emergencies. To solve these issues, this paper presents a modular context-aware access control system tailored to pervasive medical sensor networks in which the access control decisions and the response delay depend upon the health acuteness of a user. Our system extends traditional role-based access control systems by allowing for context-awareness in critical, emergency, and normal access control situations. We further present a lightweight encoding for our modular access control policies as well as an access control engine efficiently running on resource-constrained sensor nodes. Finally, we analyze how the proposed access control system suits existing security architectures for medical sensor networks.

Wireless sensor networks are going to allow for ubiquitous health monitoring, improving users’ well-being, the healthcare system, and helping to quickly react on emergency situations. Meeting the strict security needs of these ubiquitous medical applications is a big challenge, since safety and priv

Wireless sensor networks are going to allow for ubiquitous health monitoring, improving users' well-being, making the healthcare system more efficient, and helping to quickly react on emergency situations. Meeting the strict security needs of ubiquitous medical applications is a big challenge: safet

Key agreement and digital certificates allow bootstrapping secure communication links and verifying identities or information. Thus, they are the cornerstone of many basic security functionalities. However, the resource-constrained nature of wireless sensor nodes limits the use of traditional solutions in wireless sensor networks. We propose a novel scheme allowing for fast, resource-friendly, and distributed key agreement and verification of information, featuring the efficiency of symmetric-key cryptography and the functionality of public-key certificates. The core idea of our system relies on the cryptographic association of identification information with polynomial shares. This concept allows the base station of a sensor network to sign node identification and configuration information such as routing addresses or access control roles. The information is signed by means of the polynomial shares distributed to nodes creating a lightweight digital certificate for each node. The proposed system operates in a fully stand-alone and distributed way, being able to perform a combined key agreement and lightweight digital certificate verification handshake within a few milliseconds with very low memory requirements.

Wireless multi-hop networks are particularly susceptible to attacks based on flooding and the interception, tampering with, and forging of packets. Thus, reliable communication in such networks quintessentially depends on mechanisms to verify the authenticity of network traffic and the identity of communicating peers. A major challenge to achieve this functionality are the tight resource constraints of such devices as smartphones, mesh- and sensor nodes with regard to CPU, memory, and energy. Since existing approaches suffer from significant drawbacks related to functionality and efficiency, we present in this paper ALPHA, an Adaptive and Lightweight Protocol for Hop-by-hop Authentication. ALPHA establishes a verifiable notion of identity for network traffic, based on computationally cheap hash functions, enabling end-to-end as well as hop-by-hop integrity protection for unicast traffic. Our evaluation shows that ALPHA is a generic security mechanism that makes full traffic authentication and secure middlebox signaling viable in resource-constrainted multi-hop networks.

Distributed sensor network protocols, such as routing, time synchronization or data aggregation protocols make use of collaborative techniques to minimize the consumption of scarce resources in sensors. However, compromised and misbehaving nodes are a serious threat, as an attacker can employ them to eavesdrop on communication, inject forged data, or manipulate protocol operation. In this context, distributed revocation protocols play a decisive role since they allow removing compromised nodes in an efficient way. The design of distributed revocation protocols is challenging due to technical restrictions of sensor nodes, the distributed operation of sensor networks, and the presence of compromised nodes that can collude to subvert protocol operation. We propose the Cooperative Security Protocol (CSP) to enhance network security and enable efficient distributed revocation. The CSP is based on the distribution of revocation information — so called partial revocation votes — to the neighbors of a node as prerequisite to join the network. If an intruder refuses to disclose its revocation votes, the network does not allow it to join. Thus, the node is prevented from attacking the network. If the intruder cooperates by disclosing its revocation information, it can endanger the network neither, since its neighbors, which cooperate to monitor its correct operation, can use the revocation information to ban it from the network.

Compromised and misbehaving nodes in wireless sensor networks are a serious threat, as an attacker can use them to eavesdrop on communications, inject false data, or damage network protocols like routing or time synchronization. In this context, the distributed revocation of compromised nodes plays a crucial role as it enables to exclude such nodes in an efficient way without requiring the presence of a centralized security infrastructure. In this paper, we introduce a novel distributed node revocation protocol based on the disclosure of revocation information. As a prerequisite for joining the network, each node must distribute revocation votes to its neighbours. This concept allows enhancing the security level of the network in an efficient manner: if an intruder refuses to disclose its revocation information, it can neither join, and thus, nor damage the network. If the intruder collaborates by disclosing the revocation information, it can endanger the network neither, since the node's neighbours cooperate to monitor its correct operation, and would revoke it.