This course is a non-mathematical introduction to the role that cryptography plays in providing digital security for everyday applications such as the internet, mobile phones, wireless networks and cryptocurrency. In this introductory course you will develop an understanding of the functionality and purpose of the main cryptographic tools we use today. You will learn how to make decisions about which cryptographic tools are most appropriate to deploy in specific settings. You will also explore the wider infrastructure surrounding cryptography and how this impacts the overall security of systems deploying cryptography. Cryptography provides the core toolkit that underpins most digital security technologies. An understanding of what cryptography does, and its limitations, is critical to developing a wider appreciation of the security of everyday digital applications. Since cryptography provides tools for atomic security services such as confidentiality and data integrity, an appreciation of cryptography will also equips you with a fundamental understanding of what security means in cyberspace. Learning outcomes for the module. By the end of this module learners will be able to: 1. Explain the precise role that cryptography plays in the security of any digital system. 2. Appreciate the breadth of use of cryptography to support security of digital systems. 3. Identify core concepts and terminology concerning use of cryptography 4. Assess the points of vulnerability relating to cryptography in any digital system deploying it.