This course is intended to provide a general introduction to key concepts in cyber security. It is aimed at anyone with a good general knowledge of information and communications technology. The nature, scope and importance of cyber security are explained, and key concepts are justified and explored. This includes examining the types of threat that cyber security must address, as well as the range of mechanisms, both technological and procedural, that can be deployed. The role of cryptography in providing security is explored, including how algorithms and keys play their part in enabling cyber security. The key supporting function played by key management is identified, including why the use of cryptographic functions depends on it. The need for security management in an organisation is explained, and its main elements are introduced - including the key role played by risk management. The importance of standardised approaches to security management is explained, as is the notion of compliance.