To deliver security services (integrity, confidentiality, authentication, availability), it is necessary that the communicating nodes share cryptographic keys for encryption and authentication. However, it is well known that the encryption systems represent the first line of defense against all types of attacks. Furthermore, cryptographic techniques must be designed to detect the execution of the most dangerous attacks. In addition, these techniques must be small to fit the limited resources of the WSN. The aims of this chapter are to discuss the mechanisms used to secure communications; to show their main adaptations required for adoption in smart sensors, which are described in the literature, particularly in terms of key management and distribution; and finally, to detail the different solutions proposed in the literature to secure the communication of smart and constrained sensor networks in the internet of things based on cryptography and intrusion detection systems.
TopIntroduction And Background
A major development that a continuation of recent advances in communications technology and embedded systems, is “the Internet of Things (IoT).” This development will be accompanied by an evolution of technological ecosystem in all its complexity. Indeed, the global internet has evolved in recent decades of a network of computers to a network of PCs and then to one that integrates all communicating devices: RFID tags, sensor and actuator networks, vehicular networks, etc… (Maleh, Ezzati, & Belaissaoui 2016).
There are currently actively developing such a direction in the field of information technology, as “Internet of Things” - a set of different devices, sensors used previously locally and autonomously, networked through all available channels of communication, using different communication protocols between themselves and the only protocol access to a global network. In the role of a global network for the Internet of things is currently used the Internet and a common protocol is IP. Since then the number of devices connected to the internet has exceeded the population of the Earth. The number of innovations in this area is continuously increasing, indicating that the active development of the Internet of Things. Figure 1 shows the functional diagram of the Internet of Things (Maleh, Ezzati, & Belaissaoui 2016).
Figure 1. Functional diagram of the Internet of Things
To invest this new field of Internet of Things, protocols must be adapted to new constraints, security must be reinforced, because the objects have an effect in the real world and a malfunction can lead to serious consequences. As regards architecture, they must be the most generic possible to allow interconnection and they must not be linked to a particular purpose.
The 6LoWPAN protocol was developed to define the adaptation of IPv6 and how to carry IP datagrams over IEEE 802.15.4 links and perform configuration functions necessary to form and maintain an IPv6 subnet (Internet Protocol version 6) (Ashton 2011).
Generally, nodes in WSNs communicate using a Wireless Personal Area Network (WPAN) protocol such as IEEE 802.15.4 or Bluetooth standard, which makes them disconnected from a global Wide Area Network (WAN) such as the Internet. In order to handle this issue, multiple solutions exist in the literature. This convergence promotes the Internet of Things (IoT) concept, where sensor nodes (e.g., the things) represent uniquely identifiable objects connected to the Internet. Some proposals aim at realizing the convergence between Mobile Cellular Networks and WSNs or at interfacing WSNs to the core network using passive optical networks. IPv6 over Low-power Wireless Personal Area Networks (6LoWPAN) is an advanced solution to adapt the Internet Protocol version 6 (IPv6) to sensor nodes and thus provide the convergence between WSNs and traditional IP networks (Shelby & Bormann, 2011). Figure 2 presents an example of a distributed 6LowPAN.
Figure 2. Distributed sensor networks over IoT