🔐 User Authentication System (Flask)

A Flask-based User Authentication System implementing secure user registration, login, logout, and session management.
This project focuses on authentication fundamentals such as password hashing, session handling, and access control.
A minimal Todo module is included only to demonstrate authenticated user access.

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🚀 Features

• User Registration
• User Login & Logout
• Session-based Authentication
• Secure Password Hashing using bcrypt
• Protected Routes (authorized access only)
• SQLite database with SQLAlchemy ORM
• Authentication-first architecture

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🛠 Tech Stack

• Backend: Flask (Python)
• Database: SQLite
• ORM: SQLAlchemy
• Authentication: Flask Sessions
• Security: bcrypt password hashing
• Frontend: HTML, CSS (Jinja Templates)

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📂 Project Structure

User-Authentication-System/
│── app.py  
│── requirements.txt  
│── .gitignore  
│── templates/  
│   ├── login.html  
│   ├── register.html  
│   ├── index.html  
│   └── update.html  
│── static/  

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⚙️ Installation & Setup

1️⃣ Clone the repository

git clone https://github.com/your-username/User-Authentication-System.git
cd User-Authentication-System

2️⃣ Create virtual environment (recommended)

python -m venv env
env\Scripts\activate   # Windows

3️⃣ Install dependencies

pip install -r requirements.txt

4️⃣ Run the application

python app.py

5️⃣ Open in browser

http://127.0.0.1:2711

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🔐 Authentication Flow

1. User registers with email and password
2. Password is securely hashed using bcrypt
3. User logs in with valid credentials
4. Session is created and stored server-side
5. Protected routes are accessible only to authenticated users
6. Logout clears session data

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🧪 Key Routes

Route	Purpose
/register	User registration
/login	User login
/logout	End user session
/home	Protected route (authentication required)
/	Redirects based on authentication status

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🔒 Security Highlights

• Passwords are never stored in plain text
• bcrypt hashing ensures strong password security
• Session-based authentication prevents unauthorized access
• Database and environment files excluded via .gitignore

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🧩 About the Demo Module

The Todo functionality exists only as a demonstration layer to validate:

• Successful authentication
• User-specific access
• Session persistence

The primary focus of this repository is user authentication, not task management.

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📌 Future Improvements

• Flask-Login integration
• Role-based access control (RBAC)
• Password reset & email verification
• JWT-based authentication
• OAuth (Google / GitHub login)

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👨‍💻 Author

Suresh Thevar
Focused on backend development, authentication systems, and Flask-based web applications.

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⭐ If you find this useful

Give the repository a ⭐ and feel free to fork!