The Internet of Things (IoT) is the network of billions of devices, people and services to Interconnect and exchange information and useful data. The IoT applications are highly affirming to increase the level of comfort, efficiency and automations for the user. The high level of security and privacy, authentication and recovery from the attacks is required to implement IoT automated world. In this thesis I am presenting an overview of IoT layer architecture and attacks regarding security from the layer’s perspective. In addition, this thesis will provide an overview to solve the security and privacy threats. Furthermore, this paper discusses the current state of research on IoT security requirements and future research directions with respect to IoT security and privacy, a detailed review of the security challenges and sources of threat in the IoT applications is presented. Finally, this thesis presents the security issues, various emerging and existing technologies focused on achieving a high degree of trust in the IoT applications.