# A Framework for Constructing a Secure Domain of Sensor Nodes
## 2 Related Works  
In Reference [1], a taxonomic analysis of IoT security issues was conducted from the perspective of the three key layers of the IoT system model: (1) perception (related to the physical IoT sensors/actuators to support data collection and processing); (2) transportation (related to the ubiquitous access environment for the perception layer); and (3) an application layer was given. As a result of this analysis, the most critical issues were highlighted. According to this analysis, the most vulnerable layer of the presented IoT system model is the perception layer, mainly due to the physical exposure of IoT devices deployed in open environments and to the very large hardware constraints that limit the implementation of effective security measures. The critical issues are, among others [1], (1) a lack of lightweight cryptographic algorithms and effective key management; (2) a lack of lightweight trust management mechanisms; (3) insecure routing protocols; and (4) a lack of lightweight anti-malware solutions. Currently, wireless security relies mainly on cryptographic techniques and protocols that lie in the upper layers of the wireless network. At the application layer, the constrained application protocol (CoAP) has modified the widely employed datagram transport layer security to fit it into memory/energy constrained devices [2]. In Reference [3], the security and privacy issues of two important IoT technologies, namely, WSN and radio-frequency identification (RFID), are discussed, among others. In this work, it is pointed out that some of the potential threats in the RFID system are replay, synchronization, Radio Frequency (RF) eavesdropping, data alteration, etc. In the context of IoT, more security requirements are expected from the RFID system like mutual authentication, a key establishment for data confidentiality and anonymity. Currently, compared to RFID, WSN security has been raised to a much higher level. There are more and more solutions for WSN nodes (e.g., IRIS, SunSPOT) which are capable enough of performing symmetric and asymmetric cryptographic operations with hardware support. Real and suitable security solutions in WSNs such as the 802.15.4 standard, Zigbee, Bluetooth, TinySec MiniSec, Spins, SecureSens, AMSecure, and Sizzle were evaluated in Reference [4]. Some of these WSN networks offer secure modes which provide data encryption, frame integrity, and sequential freshness (such as the 802.15.4 standard and Zigbee) or authenticated encryption, such as TinySec and AMSecure. Although many of these security solutions can be used to go part of the way towards effectively securing a WSN, no one solution can provide all the necessary mechanisms for the special application of the IoT. In Reference [5], the research progress of IoT is reviewed by analyzing the security requirements and presenting the different privacy and security techniques in the IoT. In Reference [6], secure data transmission for cluster-based WSNs (CWSNs), where the clusters are formed dynamically and periodically, is investigated. Two secure and efficient data transmission protocols are proposed by using the identity-based digital signature scheme and the identity-based online/offline digital signature scheme, respectively. Cryptographic key distribution is a critical stage in the implementation of network security in critical IoT systems. Key management is one of the most important mechanisms used to secure encryption keys and their safe distribution among sensor nodes. Recently, many key management schemes have been proposed, each with its particular strengths, weaknesses, and applications under certain circumstances. The problem of key distribution in the IoT networks was recently investigated broadly by many researchers, e.g., [7; 8; 9; 10; 11; 12; 13]. For instance, in Reference [7], a key management protocol with a hybrid key management technique was proposed to meet the increasing resource-consuming security demands by asymmetric key primitives.