Applied Cryptography Lab Programs

Implemented Cryptographic Techniques

1. Classical Cryptography

• Caesar Cipher: Basic substitution cipher
• Demonstrates fundamental encryption principles
• Railfence Cipher

2. Symmetric Key Cryptography

• DES Algorithm: Data Encryption Standard
• AES Algorithm: Advanced Encryption Standard
• Explores block cipher mechanisms

3. Asymmetric Cryptography

• RSA Algorithm: Public-key cryptosystem
• Demonstrates key generation and message encryption/decryption

4. Key Exchange Protocols

• Diffie-Hellman Key Exchange: Secure key negotiation
• ElGamal Cryptographic System: Public-key cryptosystem

5. Security Techniques

• Man-in-the-Middle Attack Simulation: Demonstrates communication vulnerabilities
• Authentication using Hashing: Secure password storage technique

🛠️ Prerequisites

• GCC Compiler
• Standard C Libraries
• Math Library

💻 Compilation Instructions

Compile Individual Programs

# General Compilation Pattern
gcc -o program_name program_name.c -lm

# Example Compilations
gcc -o caesar_cipher caesar_cipher.c
gcc -o rsa_algorithm rsa_algorithm.c -lm

#For Hashing Program to compile
gcc auth_hash.c -o auth_hash -lssl -lcrypto
#For Hashing Program to Run
./auth_hash

#For installing Openssl
sudo apt-get install libssl-dev

#For AES
gcc aes_algorithm.c -o aes -lssl -lcrypto

#For DES
gcc des_algorithm.c -o des -lssl -lcrypto

Compile All Programs

# Using Makefile
make all

# Clean compiled binaries
make clean

🔍 Cryptographic Concepts Covered

• Encryption/Decryption
• Key Generation
• Hashing
• Public Key Infrastructure
• Secure Communication Protocols

📦 Project Structure

cryptography_lab/
├── caesar_cipher.c
├── des_algorithm.c
├── aes_algorithm.c
├── rsa_algorithm.c
├── diffie_hellman.c
├── elgamal_crypto.c
├── mitm_attack.c
├── hashing_auth.c
├── Makefile
└── README.md