## 3 Cyber-Attacks on SF and PA  
As suggested by recent research works, the main security aspects of SF and PA can be outlined as follows. * **Privacy** is required to keep a user from unauthorized access to to other users' information. Some attacks such as Physical Attack, Replay Attack, Masquerade Attack can lead to the violation of privacy. Several research works have focused on the privacy of SF and PA [59; 60; 61]. * **Integrity**: guarantees information not to be changed during storage or transmission. Integrity of PA and SF has been part of the topic in several research projects [62]. * **Confidentiality** of SF and PA, which protects data against unauthorised access has been of interest to a few researchers [63; 61]. * **Availability** guarantees the continuity of the provided services. Some recent research works have focused on the availability of SF and PA [64]. * **Non-Repudiation** keeps users from repudiating what they have done in the system. The importance of non-repudiation in SF and PA has received attention form a few researchers [65]. * **Trust**: makes it impossible for a user to spoof another identity. The literature in this area comes with a few research projects focusing on authenticity of SF and PA [65]. In the absence of proper provisions for security aspects discussed above, SF and PA may be exposed to a variety of attacks that may exploit these environments and related smart information systems or cause harm, stealth, unauthorized change, or destruction on them. In the following, attacks on SF and PA are classified on the basis of their target components. * **Attacks on Hardware:** Unknown or unprotected vulnerabilities of IoT and cyber-physical devices (as well as other hardware components) may be exploited by professional attackers using specialised tools [66]. As good examples for this kind of attacks, we may refer to side channel and Radio frequency (RF) jamming attacks, which can violate privacy, confidentiality, or authenticity when they hit poorly-designed IoT and cyber-physical systems [2; 66; 67; 68]. * **Side Channel Attack**[2; 69] aims at gathering unauthorized information regarding the implementation detail of a system via monitoring physical parameters such as electrical current or voltage. Attacks of this type violate the confidentiality of the system. * **RF jamming**[2; 68] attacks are caused by the open nature of wireless channels and the progress in designing jamming-resistant wireless networking systems. Attacks of this type violate the availability of the systems in the SF and PA area like a greenhouse. * **Attacks on the Network and Related Equipment:*
* target the network or the connected devices. This category of attacks can be further categorized as follows. * **Denial of Service (DoS)**[70; 71] prevents users or devices from their authorized access to a resource such as a node, a server, or a communication link/network. For example, _Radio Frequency (RF) jamming_[2; 72] overwhelms the RF spectrum used by a network aiming to deny communication services to the connected nodes. * **MITM (Man-In-The-Middle) Attacks**[2; 67; 72] transparently store and replay (or in some cases modify) data transmitted over a connection. These attacks may target the confidentiality or the integrity of the system. * **Botnets**[2; 73; 74] are groups of Internet-connected devices (remote sensors), each running one bot or more. Botnets can be used for many different purposes, including Distributed DoS (DDoS) attacks, information stealing, SPAM dissemination. They can be designed to violate availability, integrity, or trust. Cloud Computing Attacks[2] misuse cloud features such as self-provisioning, on-demand services and auto-scaling to take advantage of cloud resources. For instance, an infected virtual machine can quickly spread the infecting malware to other virtual machines via the cloud. These attacks may target non-repudiation, trust, or integrity. * **Attacks on Data:*
* hit the data while being stored, transmitted, or processed in the system.