This textbook provides an introduction to applied cryptography for students  and practitioners. We offer a carefully chosen selection of cryptographic  building blocks, algorithms, protocols, key management techniques and related methods, with a focus on what is used in practice and important to practitioners. We reinforce these with examples, applications, exercises, and real world case studies and deployments.

This book is a work in progress. As such, readers should expect that some  chapters are incomplete or entirely missing, certain sections may contain  placeholder text or missing cross-references, and the notation or  terminology may not yet be fully consistent throughout. The content will  continue to evolve as the manuscript develops, and revisions will aim to  fill in gaps, improve clarity, and ensure uniformity in style and presentation.