This book systematically explores modern cryptography, bridging the gap between theoretical frameworks and engineering practices and transforming complex mathematical concepts into accessible, real-world algorithms. It begins with classic cryptographic systems, such as symmetric ciphers (including stream and block ciphers) and public-key cryptography (e.g., RSA and ECC). Then, it advances to specialized post-quantum topics, including lattice-based cryptography and homomorphic encryption. Unlike purely theoretical treatments, this book integrates programming examples and hands-on exercises that transform abstract mathematics into tangible, logical applications. Additionally, it addresses essential security protocols, including hash functions and digital signatures, equipping readers with a structured approach to secure system design. Designed for students, researchers, and professionals in computer science and cybersecurity, this book connects foundational theory with practical engineering. Its accessible style also makes it a valuable resource for academic libraries, professional training programs, and individuals building secure systems in the digital age.
