The internet of things (IoT) is emerging as a popular future internet paradigm, in which physical entities and cyber entities are connected to form a network of networks. It is expected to enable mass participation of 'things' on mission critical services such as energy, mobility, healthcare, to name a few. Therefore, it is a matter of time for the IoT network to grow to billions of connected nodes. This leads to a variety of new, as well as existent, potential security risks whose severity depends on the environment in which the internet of things is deployed. This paper categorises the major components in the IoT domain and provides a classification of security requirements and security threats applicable to each component. It also discusses open security problems and provides directions for future research in order to address scalability and efficiency concerns, while allowing seamless introduction of new applications in this domain
