Background and Related Works. After Internet Protocol (IP) and Transmission Control Protocol (TCP) were in- troduced in the 1970s, they were investigated in the literature due to their major functionality of exchanging data packets and providing a reliable byte stream service in [119] [120]. However, as discussed in Chapter 1, single-path transport protocols such as TCP, suffer from several efficiency-related issues, e.g. failure to support multihoming and bandwidth aggregation [121]. Due to this motivation, MPTCP was proposed to provide efficient data transmission in such environments [122]. Also, Stream Control Transport Protocol (SCTP) was developed to adapt multipath transmission [25]. Multipath protocols adapt fault tolerance, i.e differ- ent paths can be assigned for different tasks. For instance, the fast paths can be used for data transmission while the slow paths could be utilised for a backup process [14]. Moreover, it has been shown that the connection-level throughput region of multi-path routing/congestion control algorithms can be larger than that of a single-path congestion control scheme [123] [124]. Various studies have been proposed to develop multi-path routing/congestion control problem including the Host Identity Protocol and Mobile IP [125]. How- ever, these solutions usually have negative impacts on the congestion price, scheduling and the possible conflict with regular TCP for existing applications. The approaches to address the multipath congestion control issues can be divided into two major categories. First, the application-based approach, where software is developed and tested on an applied benchmark while neglecting the mathe- matical formulation, convergence and stability analysis of the algorithm. For instance, a Linux based software was developed in [122]. As another example, in [126], Xxx et al. proposed a fountain code based MPTCP algorithm and they report the validation of the algorithm through simulations. The main idea behind this algorithm is to use the random nature of fountain code in transmitting data through different subflows. Further, Xxxxx et al. introduce a cross layer design which benefits from the exchange information between MAC and transport layer [127]. This scheme takes into account path condition before data transfer. The paths are evaluated according to the Frame Error Rate (FER) method and the best path is considered first for transmission. This algorithm is verified over some simulation scenarios. In [128], a Reward and Penalize ...
Background and Related Works. Xxxxx [12] introduced the wiretap channel model, which provides an approach to secure communications without relying on classical cryptographic approaches. Xxxxx showed that if the channel between the sender and intended legitimate receiver is statistically better, i.e., less noisy, than the channel from the sender to the adversary, then perfect secrecy is possible. Xxxxxx [11], and Ahlswede and Csisza´r [13] considered the problem of secret-key generation using public discussion. In this setting, the two communicating parties observe correlated versions of a common random source. Based on these observations both parties want to agree on the same secret key. The key agreement problem in CPSs has traditionally been con- sidered to be an issue to be addressed separately from the control- theoretic/physical aspects of the underlying control systems. For example, Xxxx-Xxxx et al. [14] presented three cryptographic key- establishment protocols for resource constrained CPSs, including one constructed using isogeny-based cryptography, which makes it well- suited for the post-quantum computing scenario. Sutrala et al. [15] proposed a three-factor user authenticated key agreement protocol which achieves user anonymity and untraceability for 5G-enabled softwarized industrial CPSs. Xxxxx et al. [16] proposed a cross-layer key establishment model for wireless devices in CPSs, where wireless devices extract master keys at the physical layer using ambient wireless signals. Following an information-theoretic approach, Xxxxx et al. [17] studied the outage probability for secrecy rate in multiple- input multiple-output (MIMO) systems for CPSs. Although the above reviewed key-agreement solutions target CPSs’ applications, such approaches do not explicitly take any advantage of the peculiar underlying physical dynamics of these systems. In recent years, there has been an increased interest towards the use of the physical properties of the underling control systems to provide security. Similar to the role of information theory in physical layer security [18], control theory provides a framework for the study of this issue in CPSs. Xx et al. [19] presented a key establishment scheme for networked control systems, where they exploited the common information of the physical system state for the key establishment between the sensor and the controller. Since the sensors can observe changes in the system state which are caused by the controller actions, hence, the controller and th...
Background and Related Works. Chapter two will offer all the background and prerequisite information necessary for understanding the work in this thesis. We will also have a review of works related to the ones we investigate and propose in this thesis.
