Cryptography Fundamentals: An Introduction to Secure Communication

Secure communication rests on precise definitions: confidentiality, integrity, authenticity, and resistance to chosen-message and ciphertext attacks. Classical and modern cryptography translate those goals into primitives (block ciphers, streams, hashes, MACs), modes, and protocols.

This introductory note anchors the terminology used throughout the Cryptography sequence: symmetric vs asymmetric settings, Kerckhoffs’ principle, keys vs algorithms, and the role of randomness (IVs, nonces, salt). Subsequent posts revisit each layer with proofs, constructions, and implementation pitfalls.

Use it as a map: when a lecture cites IND-CPA or EUF-CMA security, return here for the intuition before digging into proofs and exercises on Canvas.