In recent decades, the communication of electronic equipment and physical resources is combined. Internet of Things (IoT) distributes things widely in the network. The IoT is Internet-based pervasive computing, which created significant development in the recent disposition of IoT infrastructures. The IoT infrastructures lead, manage and generate large amounts of data across various applications including environmental, transportation and healthcare monitoring. In this regard, there are salient uncertainties about the use of security concepts that are frequently measured as a major concern of IoT distributed architecture design. This paper mainly focuses on the classification of IoT, novel architecture considering the sensitivity of data, IoT security layers, review of security issues and acclaimed countermeasures.