Security is essential for the Internet of Things (IoT). Cryptographic operations for authentication and encryption commonly rely on random input of high entropy and secure, tamper-resistant identities, which are difficult to obtain on constrained embedded devices. In this paper, we design and analyze a generic integration of physically unclonable functions (PUFs) into the IoT operating system RIOT that supports about 250 platforms. Our approach leverages uninitialized SRAM to act as the digital fingerprint for heterogeneous devices. We ground our design on an extensive study of PUF performance in the wild, which involves SRAM measurements on more than 700 IoT nodes that aged naturally in the real-world. We quantify static SRAM bias, as well as the aging effects of devices and incorporate the results in our system. This work closes a previously identified gap of missing statistically significant sample sizes for testing the unpredictability of PUFs. Our experiments on COTS devices of 64 kB SRAM indicate that secure random seeds derived from the SRAM PUF provide 256 Bits-, and device unique keys provide more than 128 Bits of security. In a practical security assessment we show that SRAM PUFs resist moderate attack scenarios, which greatly improves the security of low-end IoT devices.

Ageing detection and failure prediction are essential in many Internet of Things (IoT) deployments, which operate huge quantities of embedded devices unattended in the field for years. In this paper, we present a large-scale empirical analysis of natural SRAM wear-out using 154 boards from a generalpurpose testbed. Starting from SRAM initialization bias, which each node can easily collect at startup, we apply various metrics for feature extraction and experiment with common machine learning methods to predict the age of operation for this node. Our findings indicate that even though ageing impacts are subtle, our indicators can well estimate usage times with an R2score of 0.77 and a mean error of 24% using regressors, and with an Fl score above 0.6 for classifiers applying a six-months resolution.

Secure elements allow for offloading complex crypto operations from embedded devices to external, protected hardware. In this poster, we present a concept for transparently accessing multiple secure elements behind a unified API as a feature of an IoT OS.

Constrained devices on the Internet of Things (IoT) continuously produce and consume data. LwM2M manages millions of these devices in a server-centric architecture, which challenges edge net-works with expensive uplinks and time-sensitive use cases. In this paper, we contribute two LwM2M extensions to enable client-to-client (C2C) communication: (i) an authorization mechanism for clients, and (ii) an extended management interface to allow secure C2C access to resources. We analyse the security properties of the proposed extensions and show that they are compliant with LwM2M security requirements. Our performance evaluation on off-the-shelf IoT hardware reveals that C2C communication out-performs server-centric deployments. First, LwM2M deployments with edge C2C communication yield a ≈ 90% faster notification delivery and ≈ 8 times higher throughput compared to common server-centric scenarios, while keeping a small memory overhead of ≈ 8%. Second, in server-centric communication, the delivery rate degrades when resource update intervals drop below 100 ms.

LoRa is a popular wireless technology that enables low-throughput (bytes) long-range communication (km) at low energy consumption (mW). Its transmission, though, is on one side prone to interference during long on-air times, and on the other side subject to duty cycle restrictions. LoRaWAN defines a MAC and a vertical stack on top of LoRa. LoRaWAN circumvents the above limitations by imposing a centralized network architecture, which heavily reduces downlink capacity and prevents peer-to-peer communication. This makes it unusable for many deployments. The Deterministic and Synchronous Multichannel Extension (DSME) of IEEE 802.15.4e benefits of time-slotted communication and peer-to-peer communication and has the potential to overcome LoRaWAN limitations. In this work, we implement DSME on top of LoRa in the open source IoT OS RIOT and open the field for first evaluation experiments on real hardware. Initial results indicate that DSME-LoRa not only enables reliable peer-to-peer communication for constrained IoT devices, but also scales with an increasing number of nodes.

Long range radio communication is preferred in many IoT deployments as it avoids the complexity of multi-hop wireless networks. LoRa is a popular, energy-efficient wireless modulation but its networking substrate LoRaWAN introduces severe limitations to its users. In this paper, we present and thoroughly analyze DSME-LoRa, a system design of LoRa with IEEE 802.15.4 DSME as a MAC layer. DSME-LoRa offers the advantage of seamless client-to-client communication beyond the pure gateway-centric transmission of LoRaWAN. We evaluate its feasibility via a full-stack implementation on the popular RIOT operating system, assess its steady-state packet flows in an analytical stochastic Markov model, and quantify its scalability in massive communication scenarios using large scale network simulations. Our findings indicate that DSME-LoRa is indeed a powerful approach that opens LoRa to standard network layers and outperforms LoRaWAN in many dimensions.

LoRa is a popular technology that enables long-range wireless communication (kilometers) at low energy consumption. The transmission exhibits low throughput and underlies duty cycle restrictions. Long on-air times (up to seconds) and range are susceptible to interference. In parallel, common LoRa-devices are battery driven and should mainly sleep. LoRaWAN is the system that defines the LoRa PHY, MAC, and a complete vertical stack. To deal with the above limitations, LoRaWAN imposes rigorous constraints, namely, a centralized network architecture that organizes media access, and heavily reduced downlink capacity. This makes it unusable for many deployments, control systems in particular. In this work, we combine IEEE802.15.4 DSME and LoRa to facilitate node-to-node communication. We present a DSME-LoRa mapping scheme and contribute a simulation model for validating new LoRa use-cases. Our results show 100% packet delivery and predictable latencies irrespective of network size.

Common use cases in the Industrial Internet of Things (IIoT) deploy massive amounts of sensors and actuators that communicate with each other or to a remote cloud. While they form too large and too volatile networks to run on ultra-reliable, time-synchronized low-latency channels, participants still require reliability and latency guaranties. We elaborate this for safety-critical use cases. This paper focuses on the effects of networking protocols for industrial communication services. It analyzes and compares the traditional Message Queuing Telemetry Transport for Sensor Networks (MQTT-SN) with the Constrained Application Protocol (CoAP) as a current IETF recommendation, and also with emerging Information-centric Networking (ICN) approaches, which are ready for deployment. Our findings indicate a rather diverse picture with a large dependence on deployment: Publish-subscribe protocols are more versatile, whereas ICN protocols are more robust in multi-hop environments. MQTT-SN competitively claims resources on congested links, while CoAP politely coexists on the price of its performance.

Information Centric Networking is considered a promising communication technology for the constrained IoT, but NDN was designed only for standard network infrastructure. In this paper, we design and evaluate an NDN convergence layer for low power lossy links that (1) augments the NDN stateful forwarding with a highly efficient name eliding, (2) devises stateless compression schemes for standard NDN use cases, (3) adapts NDN packets to the small MTU size of IEEE 802.15.4, and (4) generates compatibility with 6LoWPAN so that IPv6 and NDN can coexist on the same LoWPAN links. Our findings indicate that stateful compression can reduce the size of NDN data packets by more than 70 % in realistic examples. Our experiments show that for common use cases ICNLoWPAN saves 33 % of transmission resources over NDN, and about 20 % over 6LoWPAN.

This paper revisits NDN deployment in the IoT with a special focus on the interaction of sensors and actuators. Such scenarios require high responsiveness and limited control state at the constrained nodes. We argue that the NDN request-response pattern which prevents data push is vital for IoT networks. We contribute HoP-and-Pull (HoPP), a robust publish-subscribe scheme for typical IoT scenarios that targets IoT networks consisting of hundreds of resource constrained devices at intermittent connectivity. Our approach limits the FIB tables to a minimum and naturally supports mobility, temporary network partitioning, data aggregation and near real-time reactivity. We experimentally evaluate the protocol in a real-world deployment using the IoT-Lab testbed with varying numbers of constrained devices, each interconnected via IEEE 802.15.4 wireless LoWPANs. Implementations are built on CCN-lite with RIOT and support experiments using various single-and multi-hop scenarios.

No abstract available.

No abstract available.

As the Internet of Things (IoT) emerges, compact operating systems (OSs) are required on low-end devices to ease development and portability of IoT applications. RIOT is a prominent free and open source OS in this space. In this paper, we provide the first comprehensive overview of RIOT. We cover the key components of interest to potential developers and users: the kernel, hardware abstraction, and software modularity, both conceptually and in practice for various example configurations. We explain operational aspects like system boot-up, timers, power management, and the use of networking. Finally, the relevant APIs as exposed by the OS are discussed along with the larger ecosystem around RIOT, including development and open source community aspects.