# A Security Framework for the Internet of Things in the Future Internet Architecture
## 2 Survey of the Evolution of IoT Architectures  
Many current IoT designs do not support applications seamlessly. Historically, stand-alone IoT systems were proprietary implementations, such as DF-1 [11], MelsecNet [12], Smart Distributed System (SDS) [13], and BACnet [14]. These fragmented solutions were typically integrated vertically and characterized as \"silo\" solutions, as shown in Figure 1a. A large number of independent legacy IoT systems co-exist across the Internet. However, their \"silo\" nature conflicts with the open spirit of the Internet and hence introduces problems of inter-operability and service-level interaction, which limits the benefits of IoT systems and could impede large-scale IoT deployment.  
As the traditional approach has many fundamental issues, overlay-based IoT architectures were proposed in an attempt to unify IoT solutions. Figure 1b shows this approach, where an overlay IoT forms a network on top of the current Internet. Standard control and data APIs were adopted to connect IoT devices and the Internet. Data from various devices in different IoT deployments is pushed to central IoT servers through IoT gateways across the Internet. IoT applications then directly subscribe to the IoT server. Low Throughput Networks (LTN) [15], Global Sensor Networks (GSN) [16; 17] and Constrained RESTful Environments (CORE) [18; 19] are representatives of the standardization efforts involving the overlay-based IoT approach. This overlay approach, however, has several weaknessesthat makes it not ideal for wide deployment. First, the merging of control and data forwarding at the central server is a bottleneck and causes scalability concerns. Second, the central IoT server is a single point failure and represents an ideal point of attack. Further, this solution does not seamlessly support mobility, which is a major requirement of the future Internet and a desirable characteristic for IoT applications.  
Recently, several works [20; 21; 22; 23; 24; 25] focus on establishing an authorization framework for IoT, and enable access control in the IoT. However, these piece-wise solutions do not provide a complete framework to address many practical issues facing IoT systems, such as identification, addressing, mobility, interoperability and scalability. Another trend to enhance IoT systems is the introduction of an abstract middleware layer to enable object virtualization, such as FI-WARE [26] and ETSI oneM2M [27]. The ETSI oneM2M introduces a Service Capability Layer as the virtualization layer, through which heterogeneous IoT devices and applications may exchange information. FI-WARE is based on ETSI oneM2M and integrates the Open Mobile Alliance Next Generation Services Interface to manage and exchange context information.  
Because of the IoT's increasing importance, future Internet designs need to design for the IoT. IoT systems can also benefit from many of the new features and protection mechanisms being proposed for the future Internet infrastructure. In particular, _NDN-based IoT_ and _MobilityFirst-based IoT_ are two representatives of future Internet based IoT systems as they support the key features of IoT as well as follow the current trends of evolving the Internet. As _data_ plays a pivotal role in the IoT, the NDN-based IoT was proposed to support content retrieval. On the other side, MobilityFirst-based IoT builds upon the MobilityFirst network [28; 29], whose major goal is to support _large scale mobility_, and therefore is strategically designed to handle scenarios where IoT devices are moving. One typical mobile IoT application scenario is vehicular networks, where sensors installed in the moving vehicles collect data and provide the data to the relevant applications through the underlying IoT infrastructure. In this paper, we use the MobilityFirst future Internet architecture as the basis for our IoT design in Section 4. We note, though, that some of our security mechanisms are general and can be applied to other future Internet based IoT systems.