Fingerprint Hash

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Your Browser Fingerprint Hash

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This is a SHA-256 hash of all your browser fingerprint data combined. It serves as a unique identifier for your browser.

1. Technical Classification

Cryptographic Hash Composite Identifier Client-Side Generated Tracking Mechanism

A fingerprint hash is a cryptographic digest that combines all collected browser attributes into a single, fixed-length identifier. Key characteristics:

2. Background & Purpose

Fingerprint hashing emerged as a way to efficiently compare and store browser fingerprints. Rather than comparing dozens of individual attributes, a single hash provides a compact, consistent identifier.

Why Hash Fingerprints?

Efficiency

Raw Fingerprint Data: ~5-10 KB of JSON data with 50+ attributes

Hash: 64 characters (256 bits), easy to index and compare

Hashing reduces storage requirements by ~99% while maintaining uniqueness.

Consistency

A hash provides a standardized format regardless of which attributes are collected. Whether tracking 20 or 100 data points, the hash is always the same length.

Privacy Theater

Hashing provides the appearance of anonymization—you can't reverse-engineer a hash to see the original data. However, if a tracker collects both the raw data and the hash, this "protection" is meaningless.

Cryptographic Hash Functions

Common algorithms used for browser fingerprinting:

3. Hash Format & Examples

SHA-256 Fingerprint Hash

Format: 64 hexadecimal characters (0-9, a-f)

Length: 256 bits = 32 bytes = 64 hex digits

Example Hashes

Chrome on Windows 11:

a7f3d9c8e2b1f4a6c9d8e7f2a1b3c5d4e8f9a2b6c7d1e3f8a9b4c2d5e6f1a8b7

Same Browser, Different Resolution:

3b8e2d7f9a1c4e6b8d3f7a2c9e4b1d6f8a3c5e9b2d7f4a8c1e6b9d3f5a7c2e4

Firefox on macOS:

d4e8f2a9b6c1e7d3f9a2b8c4e6d1f7a3c9e5b2d8f4a7c3e9b1d6f2a8c5e7d4

Hash Space

SHA-256 produces 2256 possible hashes:

What Gets Hashed?

A fingerprint hash typically includes all collected data points concatenated and hashed:

// Example: Building a fingerprint hash async function generateFingerprintHash() { // Collect all fingerprint attributes const fingerprint = { // Network userAgent: navigator.userAgent, language: navigator.language, languages: navigator.languages.join(','), timezone: Intl.DateTimeFormat().resolvedOptions().timeZone, timezoneOffset: new Date().getTimezoneOffset(), // Screen screenResolution: `${screen.width}x${screen.height}`, availableResolution: `${screen.availWidth}x${screen.availHeight}`, colorDepth: screen.colorDepth, pixelRatio: window.devicePixelRatio, // Browser platform: navigator.platform, hardwareConcurrency: navigator.hardwareConcurrency, deviceMemory: navigator.deviceMemory, cookiesEnabled: navigator.cookieEnabled, // Rendering canvas: await getCanvasFingerprint(), webgl: getWebGLFingerprint(), fonts: await detectFonts(), // ... more attributes }; // Convert to stable string representation const fingerprintString = JSON.stringify(fingerprint, Object.keys(fingerprint).sort()); // Generate SHA-256 hash const encoder = new TextEncoder(); const data = encoder.encode(fingerprintString); const hashBuffer = await crypto.subtle.digest('SHA-256', data); const hashArray = Array.from(new Uint8Array(hashBuffer)); const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join(''); return hashHex; } // Example output: // "a7f3d9c8e2b1f4a6c9d8e7f2a1b3c5d4e8f9a2b6c7d1e3f8a9b4c2d5e6f1a8b7"

4. Common Legitimate Uses

User Recognition Without Cookies

Security & Anti-Fraud

A/B Testing & Personalization

Research & Privacy Testing

5. Hash Stability Across Scenarios

Scenario Hash Changes? Trackability Impact
Same Browser, Same Session No Perfect tracking - identical hash
Browser Restart Usually No High - hash typically remains stable
Clear Cookies/Cache No High - fingerprint hash is unaffected
Window Resize Yes Medium - new hash but patterns may link to old
Browser Update Yes Medium - version change creates new hash
OS Update Yes Medium - OS version affects user agent
Install Extension Maybe Variable - depends on extension visibility
Different Browser (Same Device) Yes Low - completely different fingerprint
Incognito/Private Mode Usually No High - same hash as normal mode
VPN (Change IP) No* High - IP not included in browser fingerprint

Hash Persistence Over Time

How long does your fingerprint hash remain the same?

Fingerprint Evolution Tracking

Even when your hash changes, trackers can link your old and new fingerprints by:

6. Privacy Implications & Tracking Risks

Privacy Risk: VERY HIGH

A fingerprint hash is the ultimate tracking identifier. It's a persistent, cross-site, cookie-independent way to recognize you. Unlike cookies, you can't see it, delete it, or block it.

Why Fingerprint Hashes Are Dangerous

Invisible Tracking

Unlike cookies (visible in browser settings), fingerprint hashes are computed client-side or server-side. You have no way to know if a website is generating and storing your hash.

Cannot Be Deleted

Clearing cookies, cache, and browsing history does nothing. The hash is regenerated identically on your next visit. The only way to change it is to change your actual browser/hardware.

Cross-Site Tracking

If multiple websites use the same fingerprinting service, your hash links your activity across all of them. Companies like FingerprintJS and Iovation enable this at scale.

Cookie Resurrection (Zombie Cookies)

Sites store your hash alongside your cookies. When you delete cookies, the site recognizes you by fingerprint hash and restores your old cookies. You're never truly anonymous.

Real-World Tracking Networks

FingerprintJS (Commercial Service)

Used by 10,000+ websites for "fraud prevention." In reality:

  • Generates a visitorId (hash) that persists for years
  • 99.5% accuracy claimed for identifying returning visitors
  • Shares hashes across all client websites
  • Enables cross-site profile building

ThreatMetrix (TransUnion)

Enterprise fingerprinting for banking and e-commerce:

  • Collects 100+ attributes for comprehensive fingerprinting
  • Creates "SmartID" hash for device recognition
  • Shares data across 40,000+ customer sites
  • Links fingerprints to real identity via financial transactions

Hash-Based Discrimination

Fingerprint hashes enable sophisticated discrimination:

Hash Sharing & Data Brokers

Your fingerprint hash is likely in multiple databases:

Legal & Ethical Concerns

Regulatory Status

GDPR (Europe): Fingerprint hashes are considered personal data and require consent

CCPA (California): Consumers can request disclosure and deletion of fingerprint data

Reality: Most sites collect hashes without explicit disclosure or consent

7. How to Change or Prevent Hash Generation

Since a hash is derived from your fingerprint attributes, the only way to change it is to change those attributes. However, this is extremely difficult.

Approach 1: Change Your Fingerprint (Impractical)

To get a new hash, you need to change enough attributes:

Problem: Minor changes create a new hash but trackers can link old and new fingerprints by comparing unchanged attributes.

Approach 2: Randomize Fingerprint Data

Brave Browser (Recommended)

Randomizes canvas and audio fingerprints on each session:

  • Generates new hash per session
  • Makes long-term tracking harder (but not impossible)
  • Still functional for everyday use

Firefox + CanvasBlocker Extension

Randomizes canvas data:

  • Changes canvas hash on each load
  • Reduces fingerprint stability
  • May break some visualizations

Approach 3: Use Tor Browser (Most Effective)

Result: Everyone using Tor has the same fingerprint hash

Approach 4: Block Hash Generation (Difficult)

You cannot prevent websites from computing hashes, but you can make fingerprinting harder:

What Doesn't Work

Monitoring Your Hash

Test if your hash changes after modifications:

// Test hash stability // Generate hash now const hash1 = await generateFingerprintHash(); console.log("Hash before:", hash1); // Make a change (e.g., resize window) window.resizeTo(1024, 768); // Generate hash again const hash2 = await generateFingerprintHash(); console.log("Hash after:", hash2); // Compare if (hash1 === hash2) { console.log("⚠️ Hash unchanged - still trackable"); } else { console.log("✓ Hash changed - new fingerprint"); }
Recommended Strategy

For maximum privacy: Use Tor Browser. For practical privacy: Use Brave with fingerprint randomization. Accept that complete hash anonymity requires significant sacrifices.

8. Learn More