This book is not about deciphering the working of existing protocols. This book presents what is really needed to get a solid comprehension of the principles behind cryptography. To quote the authors: “We wrote it because people who want to learn how to design cryptographic systems must learn it somewhere, and we didn’t know of any other suitable books.”

Unlike Applied Cryptography, this book favors comprehension over exhaustivity. There is, of course, a lot of overlap between the two books, mainly concerning the first part of the classic book, but this new book is far superior as an introduction to the field. Mathematics are accessible and only present in the few chapters where they are unavoidable, if not beneficial.

As security is defined by the weakest link, this book audience is very large. Security engineers, but also developers, testers, technical writers, and even managers, will learn how protocols work in practice, in the hope to achieve the motivation of the authors “to bridge the gap between the promise of cryptography and the reality of cryptography”. I personally think I should have read this book a long time ago. Security does not have to look cryptic.