Introduction
Security in modern web applications relies heavily on tokens—small pieces of data used for authentication, authorization, and fraud prevention. From preventing CSRF attacks to ensuring secure API access, tokens play a crucial role in fortifying web applications.
Now a days the security of application is very crucial and demand will increase day by day.
In this blog, we will explore various tokens, including:
Requirements Token
Proof Token
Turnstile Token
CSRF Token
Authorization/Bearer Token
These are few of the tokens being used today, and more are in experimental phase. We all are familiar with these tokens or may be few of tokens we don't know about. Here we will see the use of each of the tokens. When and why we need to use them, how these tokens validation will secure the web application, will see in detail.
Requirements Token: Enforcing Request Validation
What it is:
A requirements token is used in web applications to enforce certain conditions before processing a request. It ensures that the incoming request meets predefined security or business logic rules.
Use Case:
- Ensuring that a request comes from a verified source
- Preventing unauthorized feature access
- Adding additional validation before authentication
Example Implementation (JWT-based)
{
"requirements_token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVC...",
"valid_until": "2025-12-31",
"required_permissions": ["UPLOAD_FILE", "MODIFY_SETTINGS"]
}
When a request is made, the server validates the requirements_token before allowing further access.
Best Practices:
- Encrypt the token using
HMACorRSA. - Store expiry timestamps to prevent reuse.
- Use short-lived tokens to limit exposure.
Proof Token: Verifying Request Authenticity
What it is:
A proof token is used to confirm that a client has previously authenticated or has the right to make a specific request. It often complements authentication mechanisms to prevent replay attacks. These tokens serve as a bridge between the initial authentication process and subsequent requests, ensuring that the client’s identity and permissions are maintained throughout a session.
Use Case:
- Ensuring non-repudiation in API transactions
- Securing OAuth flows to prevent token misuse
- Providing proof of challenge-response authentication
Example: OAuth 2.0 Proof Key for Code Exchange (PKCE)
{
"code_verifier": "random_string_123",
"proof_token": "hashed_code_verifier"
}
The hashed verifier ensures that an attacker cannot reuse an authorization code even if intercepted.
Best Practices:
- Use cryptographic hashing (SHA-256) to validate proof tokens.
- Make the proof time-sensitive to prevent replay attacks.
- Rotate proof tokens periodically.
Turnstile Token: Preventing Bot Attacks
What it is:
Turnstile tokens (e.g., Cloudflare Turnstile) are CAPTCHA-like challenge tokens used to confirm that a request comes from a human user rather than a bot. Also used in blockchain for different purposes.
Use Case:
- Preventing spam and bot traffic
- Securing form submissions (login, registration, contact forms)
- Mitigating automated attacks (credential stuffing, brute force)
Example Implementation:
{
"turnstile_token": "turnstile12345xyz",
"timestamp": "2025-01-01T12:00:00Z",
"verified": true
}
The backend verifies the token against Cloudflare’s API before accepting the request.
Best Practices:
- Integrate with Cloudflare Turnstile or Google reCAPTCHA v3.
- Ensure token validation on the backend.
- Implement progressive challenges for suspicious users.
CSRF Token: Preventing Cross-Site Request Forgery
What it is:
A CSRF token is used to protect users from Cross-Site Request Forgery (CSRF) attacks. It ensures that requests originate from the legitimate user’s session and not an attacker.
Use Case:
- Protecting form submissions (password resets, financial transactions)
- Securing API requests for authenticated users
- Preventing session hijacking attacks
Example CSRF Token Implementation (Django/Flask)
<form action="/transfer" method="POST">
<input type="hidden" name="csrf_token" value="secure_random_token_98765">
<button type="submit">Submit</button>
</form>
The server verifies the CSRF token before processing the request.
Best Practices:
- Generate a new CSRF token per session.
- Store the token in a secure HTTP-only cookie.
- Require the token for all state-changing requests (
POST, PUT, DELETE).
Authorization Token / Bearer Token
What it is:
An authorization token (or bearer token) is used in API authentication to securely grant access to protected resources.
Use Case:
- Securing API endpoints (OAuth 2.0, JWT authentication)
- User authentication for web & mobile apps
- Access control for microservices
Example: Bearer Token in an API Request
GET /api/user-profile
Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVC...
The server validates the token before allowing access.
Best Practices:
- Use short-lived tokens (e.g., 15 minutes) with refresh tokens.
- Encrypt JWT tokens to prevent tampering.
- Store tokens securely in HTTP-only cookies instead of local storage.
Each token type serves a specific security purpose in a web application:
By implementing these tokens correctly, you can significantly improve the security of your web application and prevent various attacks like CSRF, bot abuse, and unauthorized access.
Hope you find this helpful!
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Understanding Different Types of Tokens for Web Application Security