4.1 Symmetric key encryption4.1.1 The exclusive-or (XOR) operation and its role in cryptography4.1.2 One-time pads and their practical limitations4.2 Linear feedback shift registers (LFSRs)4.2.1 Implementing LFSRs4.2.2 Exploiting LFSRs4.3 RC4 encryption and Wi-Fi security4.3.1 Implementing RC44.3.2 Exploiting RC4 in WEP using the Fluhrer, Mantin, and Shamir (FMS) attack