Cryptography is a part of everyday life for almost all of us, though we may not realise we're using it. We are a far cry from the historical prediction that cryptography would only be used by militaries and governments. With vast quantities of sensitive information transferred online by individuals, companies, organizations, and nation states, cryptography is increasingly important to everyone, and most of us, often without realising, use it daily. Cryptography: A Very Short Introduction demystifies the art of cryptography by tracing its historical use, explaining how it works, and providing examples of its practical use. These include online shopping, chip and PIN bank cards, and communicating via mobile phone. While many of these uses have been mainstream for some time now, the development and deployment of cryptography has changed enormously in the last twenty years. In this second edition, Sean Murphy and Rachel Player highlight the important advances in both academic cryptography research and its everyday use. Using non-technical language and without assuming advanced mathematical knowledge, they introduce symmetric and public-key cryptography and provide a detailed discussion of the design of cryptographic algorithms that are secure against quantum computers and the development of cryptographic algorithms with advanced functionalities. They also consider the new applications of cryptography such as blockchain, secure messaging apps, and electronic voting. ABOUT THE SERIES: The Very Short Introductions series from Oxford University Press contains hundreds of titles in almost every subject area. These pocket-sized books are the perfect way to get ahead in a new subject quickly. Our expert authors combine facts, analysis, perspective, new ideas, and enthusiasm to make interesting and challenging topics highly readable.

Sean Murphy is Professor of Mathematics at Royal Holloway, University of London. He has worked in cryptography for over thirty years and has a particular research interest in symmetric cryptography. His publications include Algebraic Aspects of the Advanced Encryption Standard (2006), co-authored by Carlos Cid and Matt Robshaw. Rachel Player is a Senior lecturer in the Information Security Group at Royal Holloway, University of London. Her research considers post-quantum cryptography, and she is best known for her work in lattice-based cryptanalysis and homomorphic encryption. In 2019 she received The Radiant Award for Advancing Internet Security from the Internet Security Research Group.