a) Perceptual Layer: Usually perceptual nodes are shortof computer power and storage capacity because they are simple and with lesspower. Therefore, it is unable to apply frequency hopping communication andpublic key encryption algorithm to security protection. And it is verydifficult to set up security protection system. Meanwhile attacks from theexternal network such as deny of service also bring new security problems.
Inthe other hand sensor data still need the protection for integrity,authenticity and confidentiality. b) NetworkLayer:Although the core network has relatively complete safety protection ability,but Man-in-the Middle Attack and counterfeit attack still exist, meanwhile junkmail and computer virus cannot be ignored, a large number of data sending causecongestion. Therefore, security mechanism in this level is very important tothe IoT. c) SupportLayer: Dothe mass data processing and intelligent decision of network behaviour in thislayer, intelligent processing is limited for malicious information, so it is achallenge to improve the ability to recognize the malicious information. d)Application Layer: In this level security needs for different applicationenvironment are different, and data sharing is that one of the characteristicsof application layer, which creating problems of data privacy, access controland disclosure of information. Accordingto the above analysis, we can summarize the security requirements for eachlevel in the following, as shown in Fig. 2.
a)Perceptual Layer: At first node authentication is necessary to preventillegal node access; secondly to protect the confidentiality of informationtransmission between the nodes, data encryption is absolute necessity; andbefore the data encryption key agreement is an important process in advance;the stronger are the safety measures, the more is consumption of resources, to solve this problem, lightweightencryption technology becomes important, which includes Lightweight cryptographicalgorithm and lightweight cryptographic protocol. At the same time theintegrity and authenticity of sensor data is becoming research focus, we willdiscuss this question more in-depth in the next section. b) Network Layer: In this layerexisting communication security mechanisms are difficult to be applied.Identity authentication is a kind of mechanism to prevent the illegal nodes,and it is the premise of the security mechanism, confidentiality andinternality are of equal importance, thus we also need to establish dataconfidentiality and internality mechanism. Besides distributed denial ofservice attack (DDoS) is a common attack method in the network and isparticularly severe in the internet of thing, so to prevent the DDOS attack forthe vulnerable node is another problem to be solved in this layer. c) SupportLayer:Support layer needs a lot of the application security architecture such ascloud computing and secure multiparty computation, almost all of the strongencryption algorithm and encryption protocol, stronger system securitytechnology and anti-virus.
d) Application Layer: To solve thesecurity problem of application layer, we need two aspects. One is theauthentication and key agreement across the heterogeneous network, the other isuser’s privacy protection. In addition, education and management are very importantto information security, especially password management.