Cryptography and Network Security Laboratory

This cryptography laboratory manual provides comprehensive hands-on experience implementing both classical and modern security algorithms through sixteen structured experiments. Students begin with classical ciphers-Caesar, Playfair, Hill, Vigenere, and Rail Fence-learning substitution and transposition fundamentals while implementing them in C. These reveal core cryptographic concepts: key spaces, frequency analysis resistance, and mathematical transformations. Modern algorithms follow: DES introduces block cipher design with Feistel networks and S-boxes. RSA demonstrates public-key cryptography through prime numbers and modular exponentiation. Diffie-Hellman enables secure key exchange over insecure channels. Hash functions MD5 and SHA-1 create digital fingerprints for integrity verification, while Digital Signature Standard provides authentication and non-repudiation. The manual then transitions from implementation to practical security tools. GnuPG enables encrypted email and file storage. KF Sensor deploys honeypots to attract and analyze attackers. GMER detects hidden rootkit processes. NetStumbler audits wireless networks for vulnerabilities.