Feistel Ciphers (DES, Tirpple DES)

Feistel Ciphers, with a focus on DES (Data Encryption Standard) and Triple DES (3DES), are discussed as significant advancements in encryption. Developed by Horst Feistel, these ciphers employ a symmetric key encryption scheme, dividing the plaintext into blocks and applying multiple rounds of substitution and transposition operations. The lecture elaborates on the structure and operation of DES, highlighting its key components such as the initial and final permutations, the key schedule, and the Feistel round function. Additionally, Triple DES, which applies DES encryption three times sequentially, is explored for enhanced security. By studying Feistel Ciphers, particularly DES and Triple DES, students gain insight into widely used encryption standards and their role in securing sensitive data. This understanding forms a solid foundation for further exploration into modern encryption algorithms and protocols.