Security Architecture

A technical deep dive into how GhostPaste keeps your code private

Zero-Knowledge Architecture

GhostPaste implements true zero-knowledge encryption. This means we have zero ability to access your plaintext data, zero knowledge of your encryption keys, and zero way to comply with requests to decrypt your data.

What You Can See

Your original code and files
The encryption/decryption key
When and how to share
Complete control over your data

What We Can't See

Your unencrypted code
Your encryption keys
What your paste contains
Who you share with

Encryption Implementation

Encryption Flow

Key Generation

A cryptographically secure random 256-bit key is generated using crypto.getRandomValues()

Client-Side Encryption

Your data is encrypted using AES-256-GCM with a unique IV for each encryption

Binary Format

Encrypted data is packed into a custom binary format with version info and file metadata. Enforces limits: 500KB/file, 5MB total, 20 files max

Server Storage

Only the encrypted blob is sent to and stored on our servers

Key in URL Fragment

The encryption key is placed in the URL fragment (after #) which never reaches any server

Cryptographic Details

Encryption Algorithm: AES-256-GCM (Galois/Counter Mode)
Key Size: 256 bits (32 bytes)
IV Size: 96 bits (12 bytes) - unique per encryption
Auth Tag Size: 128 bits (16 bytes)

Infrastructure Security

Hosting: Cloudflare Workers (Edge Computing)
Storage: Cloudflare R2 (S3-compatible)
Transport: TLS 1.3+ enforced
DDoS Protection: Cloudflare automatic protection
Data Residency: Global edge locations

Password Protection & Authentication

GhostPaste offers optional password protection for your gists, allowing you to control who can edit or delete them. This feature uses industry-standard password hashing to ensure your password remains secure even if our servers are compromised.

How Password Protection Works

Password Creation

When you set a password, it's sent securely to our server where it's immediately hashed using PBKDF2-SHA256 with 100,000 iterations and a random salt

Secure Storage

Only the hash and salt are stored in our database. Your original password is discarded immediately after hashing

Edit Verification

When editing, your password is sent to the server where it's re-hashed with the same salt and compared against the stored hash

Zero Knowledge

We can verify your password without ever knowing what it is, maintaining zero-knowledge principles

Hashing Specifications

Algorithm: PBKDF2 with SHA-256
Iterations: 100,000 (OWASP recommended minimum)
Salt Size: 128 bits (16 bytes) of cryptographically secure random data
Hash Output: 256 bits (32 bytes)
Password Requirements: 4-20 characters with at least one letter and one number

Security Benefits

Brute-force resistance: 100,000 iterations make cracking computationally expensive
Rainbow table protection: Unique salts prevent precomputed attacks
Server compromise safety: Even if hashes leak, passwords remain protected
Zero-knowledge: We never see or store your actual password
Timing attack protection: Constant-time comparison prevents timing-based attacks

Password Best Practices

Use a unique password not used elsewhere

Consider longer passwords for sensitive data

Include numbers, letters, and symbols

Avoid common patterns (1234, password)

Don't reuse passwords from other services

Remember: password protects edits, not viewing

Data Retention & Cleanup

Automatic Expiration

All gists have mandatory expiration times (default: 7 days)
Encrypted data is permanently deleted after expiration
No data recovery possible after expiration
Metadata (size, timestamp) is also purged

View-Once Security

Gist is immediately deleted after first view
Perfect for sharing sensitive credentials
Prevents accidental re-access
Link becomes permanently invalid

Security Guarantees

End-to-End Encryption

Data is encrypted before leaving your browser and decrypted only in the recipient's browser

Forward Secrecy

Each paste uses a unique encryption key that's never reused

Authenticated Encryption

GCM mode ensures data integrity and authenticity

Browser Security & Privacy

What's Encrypted

All file contents and code
File names and descriptions
Programming language information
Number of files in gist

Visible Metadata

Gist ID and creation timestamp
Expiration time and view-once status
Encrypted blob size (but not content size)
Whether password protection is enabled

Browser Requirements

Modern browser with Web Crypto API support

JavaScript enabled for encryption/decryption

HTTPS required (enforced automatically)

Chrome 37+, Firefox 34+, Safari 11+

Mobile browsers with crypto support

Internet Explorer not supported

Threat Model

What We Protect Against

Server compromise - encrypted data remains secure

Network eavesdropping - TLS + client encryption

Legal requests - we cannot decrypt your data

Data breaches - only encrypted blobs exposed

Replay attacks - unique IVs and auth tags

Tampering - GCM authentication detects changes

Limitations

Compromised device: If your device is compromised, attackers can access decrypted data

Phishing: Always verify you're on ghostpaste.dev before entering passwords

Link sharing: Anyone with the complete link can decrypt - share carefully

Browser security: We rely on browser's WebCrypto implementation

Trust, but Verify

Don't just take our word for it. GhostPaste is fully open source, allowing you to:

Audit the Code

• Review our encryption implementation
• Verify no backdoors or data collection
• Check for security vulnerabilities
• Ensure keys stay client-side

View Source Code

Run Your Own Instance

• Deploy to your own infrastructure
• Control your data completely
• Customize for your needs
• Perfect for sensitive environments

Deployment Guide

Security Disclosure

Found a security vulnerability? We appreciate responsible disclosure.

Please review our security policy for responsible disclosure guidelines:

View Security Policy

We'll acknowledge your report within 48 hours and work with you to understand and resolve the issue quickly.

Security Through Transparency

Our code is open, our encryption is proven, and your data remains yours.

Try It Now Learn More