Perfect Secrecy: One-time Pad

This lecture covers the concept of perfect secrecy in cryptography, focusing on the one-time pad encryption method. It explains the assumptions and properties required for achieving perfect secrecy, including the key length and the independence between plaintext and ciphertext. The lecture also delves into attacks on encryption systems, such as cipher-text only attacks and known plaintext attacks, highlighting the importance of key security. Additionally, it discusses the Vigenère cipher and its relation to multiple Caesar ciphers, emphasizing the challenges of breaking encryption with different key lengths. The instructor provides insights into the theoretical foundations of modern cryptography and the significance of key assumptions in ensuring secure communication.