Symmetric Encryption: Block Ciphers and Modes of Operation

This lecture covers the fundamentals of symmetric encryption, focusing on block ciphers like DES, 3DES, and AES, as well as modes of operation such as ECB, CBC, OFB, CFB, CTR, and XTS. The instructor explains the concept of cryptographic primitives, the structure of block ciphers, and the importance of key generation. Various attacks on DES, including weak keys and exhaustive searches, are discussed. The lecture also delves into the Advanced Encryption Standard (AES), highlighting its development process and key features. Additionally, the lecture explores the Rijndael structure, key expansion techniques, and different modes of operation like ECB and CBC.