🔐 Unique Encryption Algorithm Based on Feistel Cipher

This project is a custom-designed symmetric encryption algorithm built upon the Feistel cipher structure. It combines a strong key generation process using SHA-256 and PBKDF2 with multiple layers of substitution and permutation to ensure high security and avalanche effect. A Flask web interface is provided for practical interaction with the encryption system.

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📌 Project Overview

This implementation:

• Uses a 128-bit block size split into two 64-bit halves.
• Performs 16 Feistel rounds to enhance security.
• Applies confusion and diffusion via:
  • XOR with subkey
  • Bit rotation
  • Byte reversal (stack-based)
  • Bit inversion
  • Modular hexadecimal transformation

Key generation is dynamic and supports both user-provided and randomly generated keys. It incorporates salting, hashing (SHA-256), and round-number-based derivation to ensure cryptographic strength and randomness.

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🚀 Features

• Feistel cipher-based encryption/decryption
• Dynamic round-key generation with SHA-256
• Avalanche effect visual demonstration
• Web interface using Flask for user interaction
• Modular and readable Python code

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🛠 Prerequisites

Ensure you have:

• Python 3.7 or higher
• pip installed

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📦 Installation

1. Clone this repository or download the ZIP.
2. Open your terminal and navigate to the project directory.
3. Install dependencies:

   pip install -r requirements.txt