Malware commonly encrypts its traffic (stolen data sent to a command-and-control server) and internal strings (like URLs and configurations) to prevent security systems from recognizing malicious content.  Cryptography fundamentals, classical ciphers, bitwise operations, XOR functions, and XOR cipher detection and decryption techniques, and showcase a practical example of how to decrypt malware C2 communication encrypted with XOR.  Common encryption methods: XOR Rc4 AES DES 3DES (Tripple DES) Main concepts in encryption are:

Source: GBHackers