CRYPTOGRAPHY: The Key to Digital Security

If you use a mobile phone, connect to a WiFi network, withdraw cash from an ATM, or watch a film on Netflix, you are using cryptography. Cryptography secures 7 billion bank cards, 55 billion daily WhatsApp messages and three quarters of the connections made on the world wide web. This go-to book on the subject explains the technology and its implications in a way that the averagely intelligent person can understand. Cryptography is essentially an application of mathematics and has indirectly given rise to popular movies such as Enigma and Skyfall. You can get by without being aware of it, but in a series of imaginary day to day scenarios the author explains that knowing a bit about how it works can help make you more secure. Around 30% of fraud in the business world concerns cybercrime, and the cybersecurity firm Norton estimates that in 2017 there were 978 million global victims. The downside of cryptography is that on the one hand it protects the ordinary user in cyberspace, but it can also be used to protect organised crime, terror cells and child pornographers. In 2017 in the UK forty hospitals found their computer systems had been disabled by attackers who wanted a ransom to return the systems to normal, raising moral questions about the way we handle crime. Cryptography is political and there are no simple answers between freedom and control. The author explains keys and algorithms, bits and bytes. An encryption algorithm takes two core ingredients - plain text and key - and mixed them up to produce a cyphertext. If the text does not fit the bytes, padding is used. Then the bytes, columns and rows are all scrambled more than once. But who exactly is threatening us out there? The author considers an imaginary child, twelve year old Chloe, who uses social media, and the potential dangers. The book concludes by looking at possible future scenarios. 308pp.