Block Ciphers and Cryptanalysis

This report gives a basic introduction to block cipher design and analysis. The concepts and design principles of block ciphers are explained, particularly the class of block ciphers known as Feistel ciphers. Some modern block cipher cryptoanalysis methods are demonstrated by applying them to variants of a weak Feistel cipher called Simplified TEA (STEA), which is based on the Tiny Encryption Algorithm (TEA).