Cryptography

This course is designed to give you a solid foundation in how information is protected in the digital age. Step into the world of cryptography—the science behind secure communication. This course aims to prepare you for an exciting and in-depth journey into the world of modern cryptography. Designed for undergraduate students, it introduces the core principles, mathematical foundations, and practical applications that make secure digital communication possible today. You will start by learning the basics of cryptographic systems, including classical ciphers (block and stream), modular arithmetic, and finite fields—tools that form the backbone of encryption. As the course progresses, you will explore key mathematical ideas like discrete logarithms and primality testing, which support widely used algorithms such as RSA and digital signatures. You will then dive into modern cryptographic techniques, including symmetric encryption (DES, AES), public-key cryptography, hash functions, authentication methods, and key management strategies. You will also be introduced to advanced topics like linear and differential cryptanalysis, perfect secrecy, and cryptographic protocols that ensure secure communication. A special focus will be placed on theoretical tools such as interactive proofs, zero-knowledge proofs, probabilistic algorithms, and pseudo-randomness—concepts that help build secure systems even in hostile environments. To connect theory with practice, the course includes real-world applications like email and web security, digital rights management, firewalls, and protection against malware. By the end of the course, you will have a solid understanding of both the theory and practice of cryptography, preparing you for further studies in cybersecurity or careers in secure software development and information security. This course will emphasise on principles and practice of cryptography and network security: classical systems, symmetric block ciphers (DES, AES, other