In this book, the most important cryptographic algorithms, protocols and constructions of the last decades are explained and justified. The topics discussed range from public-key cryptography and zero-knowledge protocols to cryptography in blockchains, the Tor network and quantum. The authors succeed in presenting these complex topics in a simple and clear manner. Hardly any prior knowledge is required, as all the necessary mathematical and cryptographic background is provided in the book. The book has a modular structure so that the individual chapters can be read independently of one another. Each topic is presented at different levels: First, the concept is described as a mental model, then it is studied from a mathematical point of view, and finally the strengths and weaknesses of the respective protocol are discussed. The focus is on a high-level perspective rather than full formal proofs. The book is suitable for undergraduate students (e.g., in mathematics, computer science, electrical engineering) as well as for Internet users, tech managers, software developers and data protection/data security officers. This book is an expanded translation of the original German 9th edition Moderne Verfahren der Kryptographie by Albrecht Beutelspacher, Jörg Schwenk and Klaus-Dieter Wolfenstetter, published by Springer-Verlag GmbH Germany, part of Springer Nature in 2022. The translation was done with the help of artificial intelligence. The authors have subsequently revised and extended the text to refine the readability of the text, and to add novel content.
