The issues this thesis aims to tackle are those associated with the security of Cyber physical systems (CPS) in chemical plants. These systems are designed to maintain certain precise processes – such as gas flow, temperature, pressure, and more – in order to carry out chemical reactions. Problems with security are two fold as physical tampering could cause catastrophic damage instantly, and cyber attacks can manipulate CPS into operating with settings well outside their pre-designed safety limits. Security against one or the other is not enough – and while physical security is merely limited by the design of chemical plants and the multiple remote access points a criminal can reach, the cyber domain is a much newer and more intangible threat to chemical plants. The thesis proposes security based around the properties of the respective system (rather than a blanket security system), as well as a Multiple Security Domain Nondeducibility (MSDND) framework that would detect when a sensor was under attack.
