🔐 Cryptography Project - S-DES & S-AES Implementation

A comprehensive implementation of Simplified Data Encryption Standard (S-DES) and Simplified Advanced Encryption Standard (S-AES) with support for multiple operation modes and various file types.

✨ Features

🔢 Encryption Algorithms

• S-DES (Simplified Data Encryption Standard) 🛡️

  • 10-bit key encryption
  • 8-bit block cipher
  • Educational implementation of DES principles

• S-AES (Simplified Advanced Encryption Standard) 🔐

  • 16-bit key encryption
  • 16-bit block cipher
  • Simplified version of AES for learning purposes

🔄 Operation Modes

Both S-DES and S-AES support the following 5 operation modes:

1. ECB (Electronic Codebook) 📚

   • Each block encrypted independently
   • Simple but less secure for repetitive data

2. CBC (Cipher Block Chaining) 🔗

   • Each block XORed with previous ciphertext
   • Requires initialization vector (IV)

3. CFB (Cipher Feedback) 🔄

   • Stream cipher mode
   • Encryption of IV creates keystream

4. OFB (Output Feedback) 🔁

   • Stream cipher mode
   • IV encrypted repeatedly to generate keystream

5. CTR (Counter) 🔢

   • Stream cipher mode
   • Counter encrypted to generate keystream

📁 Supported File Types

• Images: Process image files with encryption/decryption 🖼️
• Videos: Handle video file encryption (.mp4 format) 🎥
• Text Files: Encrypt/decrypt text documents (.txt format) 📄
• JSON: Configuration and key files 📋

🚀 Additional Features

• Brute Force Attack: Implement brute force decryption for text files 💥
• Key Generation: Automatic key generation utilities 🔑
• File I/O: Robust file handling for various formats 📂

Project Structure 📁

Crypto/
├── s-aes/ 🔐
│   ├── CBC.py          # 🔗 Cipher Block Chaining mode
│   ├── CFB.py          # 🔄 Cipher Feedback mode
│   ├── CTR.py          # 🔢 Counter mode
│   ├── ECB.py          # 📚 Electronic Codebook mode
│   ├── OFB.py          # 🔄 Output Feedback mode
│   ├── S-AES.json      # ⚙️ Configuration file
│   ├── S_AES_Decryption.py  # 🔓 Main decryption module
│   ├── S_AES_Encryption.py  # 🔒 Main encryption module
│   ├── key.json        # 🔑 Key storage
│   ├── text.txt        # 📄 Sample text file
│   ├── video.mp4       # 🎥 Sample video file
│   └── Class Diagram1.jpg   # 📊 Project documentation
│
├── s-des/ 🛡️
│   ├── CBC.py          # 🔗 Cipher Block Chaining mode
│   ├── CFB.py          # 🔄 Cipher Feedback mode
│   ├── CTR.py          # 🔢 Counter mode
│   ├── ECB.py          # 📚 Electronic Codebook mode
│   ├── OFB.py          # 🔄 Output Feedback mode
│   ├── S-DES.json      # ⚙️ Configuration file
│   ├── S_DES_decryption.py  # 🔓 Main decryption module
│   ├── S_DES_encryption.py  # 🔒 Main encryption module
│   ├── text.txt        # 📄 Sample text file
│   ├── text_recovered.txt   # 🔄 Recovered text file
│   ├── video.mp4       # 🎥 Sample video file
│   └── Class Diagram1.jpg   # 📊 Project documentation
│
├── .gitignore          # 📝 Git ignore rules
├── README.md           # 📖 Project documentation
└── key.json            # 🔑 Global key storage

🚀 Installation

1. Clone the repository:

git clone [repository-url]
cd Crypto

2. Install required dependencies:

pip install -r requirements.txt

💻 Usage

S-AES Implementation 🔐

Encryption 🔒

from S_AES_Encryption import encrypt_file

# Encrypt a text file
encrypt_file('input.txt', 'output.enc', key='your-16-bit-key', mode='CBC')

# Encrypt an image
encrypt_file('image.jpg', 'image.enc', key='your-16-bit-key', mode='ECB')

Decryption 🔓

from S_AES_Decryption import decrypt_file

# Decrypt a file
decrypt_file('encrypted.enc', 'decrypted.txt', key='your-16-bit-key', mode='CBC')

S-DES Implementation 🛡️

Basic Usage

from S_DES_encryption import s_des_encrypt
from S_DES_decryption import s_des_decrypt

# Encrypt/decrypt with S-DES
plaintext = "Hello"
key = "1010000010"  # 10-bit key
encrypted = s_des_encrypt(plaintext, key)
decrypted = s_des_decrypt(encrypted, key)

🔧 Operation Modes

ECB Mode 📚

from ECB import encrypt_ecb, decrypt_ecb
result = encrypt_ecb(data, key)

CBC Mode 🔗

from CBC import encrypt_cbc, decrypt_cbc
result = encrypt_cbc(data, key, iv)

CFB Mode 🔄

from CFB import encrypt_cfb, decrypt_cfb
result = encrypt_cfb(data, key, iv)

OFB Mode 🔁

from OFB import encrypt_ofb, decrypt_ofb
result = encrypt_ofb(data, key, iv)

CTR Mode 🔢

from CTR import encrypt_ctr, decrypt_ctr
result = encrypt_ctr(data, key, counter)

💥 Brute Force Attack

For educational purposes, implement brute force attacks on encrypted text:

def brute_force_text(encrypted_text, known_plaintext=None):
    """
    Attempt to decrypt text using brute force method 🔓💪
    """
    # Implementation for trying all possible keys
    pass

📂 File Format Support

Text Files (.txt) 📄

• Direct encryption/decryption of text content
• Support for various encodings (UTF-8, ASCII)
• Includes text_recovered.txt for brute force results

Images 🖼️

• Pixel-level encryption
• Maintains image structure while encrypting pixel data
• Supports common formats (JPEG, PNG)

Videos (.mp4) 🎥

• Frame-by-frame encryption
• Maintains video container structure
• Encrypts video stream data

Security Notes

⚠️ Educational Purpose Only: This implementation is designed for educational purposes to understand cryptographic principles. Do not use for production security applications.

• S-DES and S-AES are simplified versions with reduced security
• Real-world applications should use proven cryptographic libraries
• Keys should be generated using cryptographically secure random generators

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests for new functionality
5. Submit a pull request

Educational Resources

This project demonstrates:

• Block cipher operation modes
• Symmetric encryption principles
• File handling in cryptographic contexts
• Brute force attack methodologies
• Key management practices

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• Based on educational materials for cryptography courses
• Implements simplified versions of industry-standard algorithms
• Designed for learning and demonstration purposes

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