🛡️ Secure Authentication System (CLI)

A robust, CLI-based User Authentication System engineered in Python.
This project demonstrates core cybersecurity concepts including SHA-256 Hashing, Cryptographic Salting, and Secure Data Persistence without using external databases.

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🚀 Key Features

• 🔒 SHA-256 Hashing: Passwords are never stored in plaintext. They are converted into a secure hash before storage.
• 🧂 Cryptographic Salting: Uses os.urandom(16) to generate a unique random salt for every user. This makes Rainbow Table Attacks impossible.
• 📂 Custom File Database: Implements a custom CRUD logic to store credentials in a .txt file format securely.
• 🚫 Duplicate Prevention: Logic to check if a username already exists before registration.
• ✅ Zero-Knowledge Verification: The system verifies passwords by comparing hashes, ensuring the actual password is never exposed during the login process.

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🛠️ Tech Stack

• Language: Python 3.x
• Modules: hashlib, os (Standard Library - No pip install required)
• Interface: Command Line Interface (CLI)

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⚙️ How It Works (Security Logic)

1. Registration:

   • User enters a password.
   • System generates a random 16-byte Salt.
   • System combines Salt + Password and hashes it using SHA-256.
   • Stores Username | Salt | Hash in the database.

2. Login:

   • User enters username & password.
   • System retrieves the stored Salt for that user.
   • System hashes the input password with the retrieved salt.
   • Compares the New Hash vs Stored Hash.
   • Access Granted only if they match perfectly.

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⚠️ Disclaimer

This project is developed for educational purposes to demonstrate secure authentication flows. It is designed to show the difference between simple coding vs. secure engineering.

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👨‍💻 Developed by [Prathish Kumar S]

Aspiring Backend & Security Engineer