Foundations of Cryptography and Information Theory

How do we guarantee that our digital communications remain private and secure in an interconnected world? Understanding the mathematical and theoretical foundations of security is essential for anyone looking to build, analyze, or work with secure digital systems. This written course bridges the gap between information theory and practical cryptography, giving you a deep conceptual understanding of how data is encoded, transmitted, and protected. You will transition from learning basic definitions to confidently evaluating security systems from both a computational and information-theoretic perspective. What you'll learn: - Understand the core concepts of information theory, including entropy, source coding, and channel capacity. - Analyze classic and modern cryptographic systems using Kerckhoffs's Principle and threat modeling. - Contrast the critical differences between computational security and absolute, information-theoretic security. - Evaluate how entropy and attacker knowledge impact the strength of encryption keys and protocols. - Explore foundational principles of modern secure protocols, including basic zero-trust security concepts and post-quantum cryptography. You will start with the absolute basics of information representation and security definitions before moving on to entropy, mathematical limits of communication, and core cryptographic primitives. Through clear written explanations and logical exercises, you will build a strong conceptual foundation in modern data protection. This course is designed for beginners in cybersecurity, computer science, or data engineering, requiring no prior background in advanced mathematics or cryptography. Start reading today to unlock the fundamental principles that keep the digital world secure.