🔐 OTP-Based User Authentication System (Email Verification) — Python + MySQL

A complete command-line authentication system featuring secure password hashing, email-based OTP verification, SQL injection protection, and modern Python standards. Perfect for internal tools, admin portals, or learning about secure authentication systems.

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🚀 What is This?

This is a Python-powered authentication system that leverages:

✅ One-Time Passwords (OTP) via email for verifying users ✅ Secure login/registration with bcrypt hashing ✅ SQL Injection detection & prevention ✅ OTP expiration logic (auto-cleans expired codes) ✅ User data storage in MySQL ✅ Command-line Interface for interaction

Built to be secure, extendable, and practical, this app simulates real-world login mechanics in a local CLI environment.

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💡 Why Use This?

Whether you're:

• A student learning about authentication & security
• A backend dev testing email-verification workflows
• An engineer building a prototype login system
• Or just someone who wants to learn real security concepts in Python

...this project covers the core foundation of secure authentication systems with simplicity and real-world logic.

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📸 Screenshot

Below: OTP verification screen in CLI

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🧰 Features at a Glance

Feature	Description
✅ Email OTP Verification	Sends time-limited OTP via Gmail SMTP
✅ OTP Expiration (5 mins)	Auto-expires and deletes stale OTPs from database
✅ Password Hashing	Uses bcrypt for industry-standard hashing
✅ SQL Injection Protection	Detects and blocks known SQL injection patterns during login
✅ Strong Password Enforcement	Enforces rules (uppercase, digit, special chars, etc.)
✅ User & Login Separation	Stores user details and login credentials in separate normalized tables
✅ Full CLI Interface	Clean terminal interface for registering and logging in

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🛠 Tech Stack

• Python 3
• MySQL
• SMTP (Gmail App Password)

📦 Key Python Libraries

• bcrypt – Password hashing
• pyotp – OTP generation
• mysql-connector-python – MySQL connection
• smtplib – Sending emails
• hashlib, re, datetime, getpass, time – Core utilities

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📁 Project Structure

OTP_System/
│
├── menu.py                # Main menu (signup / login)
├── Login.py               # Registration & login logic
├── otp_authenticate.py    # OTP generation, email sending, expiration logic
├── configure.py           # Email config (company email, app password)
├── database.py            # MySQL DB connection
├── requirements.txt       # Dependencies list
├── README.md              # Project documentation
└── assets/
    └── project-screenshot.png  # CLI screenshot image

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🔧 Installation & Usage

1️⃣ Clone the Repo

git clone https://github.com/yourusername/otp-auth-system.git
cd otp-auth-system

2️⃣ Install Dependencies

pip install -r requirements.txt

3️⃣ Configure Gmail App Password

Update configure.py with your email and Gmail App Password:

company_email = "yourcompany@gmail.com"
company_email_password = "your_app_password"

✅ Make sure 2FA is enabled on your Gmail account. Generate a Gmail App Password to use here.

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4️⃣ Run the App

python menu.py

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🧪 MySQL Setup

Before running, make sure your MySQL database has the following tables:

USERS Table

CREATE TABLE USERS (
  user_id INT PRIMARY KEY AUTO_INCREMENT,
  first_name VARCHAR(100),
  last_name VARCHAR(100),
  username VARCHAR(100) UNIQUE,
  email VARCHAR(100)
);

LOGIN Table

CREATE TABLE LOGIN (
  login_id INT PRIMARY KEY AUTO_INCREMENT,
  username VARCHAR(100),
  password VARCHAR(255)
);

OTP Table

CREATE TABLE OTP (
  otp_id INT PRIMARY KEY AUTO_INCREMENT,
  otp_code VARCHAR(255),
  email VARCHAR(100),
  exp_time TIMESTAMP
);

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✅ Security Considerations

• 🔒 Passwords are hashed with bcrypt before storing
• 🧪 OTPs are one-time-use and expire in 5 minutes
• ⚠️ SQL injection detection via regex pattern checks
• 🚫 Email + password fields are validated & sanitized

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📦 Dependencies

bcrypt==4.1.2
pyotp
mysql-connector-python
stdiomask

Standard libraries used: hashlib, smtplib, email, re, datetime, getpass, time

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🙋 FAQ

Q: Can I use another SMTP provider? A: Yes! Simply update the SMTP section in otp_authenticate.py. Any provider that supports SMTP can work.

Q: Can this run on Mac/Linux? A: Yes. This is cross-platform — as long as Python and MySQL are installed.

Q: Can I customize OTP length/expiration? A: Absolutely. Modify the generate_and_send_otp function in otp_authenticate.py.

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👤 Author

• GitHub: @SecureAuditX
• Email: abdulkarimumar86@gmail.com
• Twitter: @SecureAuditX

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🤝 Contribute

Found a bug? Want a new feature? Fork this repo and open a PR or raise an issue!

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📜 License

This project is licensed under the MIT License — feel free to use and modify it.