In this book, readers will find an exhaustive guide on cryptography for modern blockchain technology. It starts with an understanding of how blockchain trust minimization emerges from cryptographic principles for decentralization, security, privacy, or trust in distributed systems. Starting with an understanding of inadequacies in centralized systems, followed by an introduction to blockchain as a technology for trust minimization. Next is an exposition on attack surfaces, real-life security incidents, and what can be derived from real-life experiences in the area of blockchain.Learners will have a comprehensive insight into digital signatures, ranging from traditional methods to efficient designs that are used in scalable and privacy-preserving blockchains. The text covers the way digital signatures work in the context of Bitcoin, Ethereum, and business networks, with particular emphasis on efficiency, privacy, anonymity, and accountability. A comprehensive treatment is also given to the integration of blockchains with Internet of Things networks, specifically in resource-constrained networks, fog computing, and privacy-preserving networks. The text offers an in-depth analysis of consensus schemes and their connections between the theories of distributed systems and cryptography. We learn about proof of work, proof of stake, hybrid schemes, and cryptographic primitives that underpin them. A key focus of the book is future readiness. Authors have explored post quantum threats to blockchain security and learn how lattice based, hash based, and hybrid cryptographic schemes can protect systems against quantum adversaries. Migration strategies, enterprise frameworks, and experimental deployments are discussed to bridge theory and practice.This book is written for undergraduate students, researchers, graduate students, and professionals seeking a deep yet structured understanding of blockchain cryptography. It combines theory, real world examples, and design insights to help you analyze, build, and secure next generation blockchain systems.