🔐 Secure Pastebin (Self-Hosted Ver)

Self-Hosted, Zero-Knowledge, End-to-End Encrypted Pastebin

Share sensitive messages securely. Server cannot read your data. Ever.

🌐 Live Demo: https://sphost.theazizi.ir
☁️ Cloudflare Worker Version

---

✨ Features

Feature	Description	Security Impact
🔒 E2E Encryption	AES-256-GCM in browser before transmission	Server sees only ciphertext
🛡️ Zero-Knowledge	Server has zero access to keys or plaintext	Mathematically provable
🔑 Password Protection	PBKDF2 with 100,000 iterations	Brute-force resistant
🔥 Burn After Read	Auto-delete after first access	Forward secrecy
⏱️ Auto-Expiration	1 hour to 30 days configurable	Limits exposure window
🌐 RTL Support	Persian, Arabic, Hebrew typography	Accessibility
📱 Responsive	Mobile-first design	Usability

---

🔐 Cryptography Architecture

Zero-Knowledge Proof

┌────────────────────────────────────────────────────────────────┐
│                    ZERO-KNOWLEDGE GUARANTEE                    │
├────────────────────────────────────────────────────────────────┤
│                                                                │
│   USER BROWSER                      SERVER / DATABASE          │
│   ─────────────                     ─────────────────          │
│                                                                │
│   ┌─────────────┐                   ┌─────────────────┐        │
│   │ Generate    │ ──NOT SENT──────► │                 │        │
│   │ AES-256 Key │                   │  NO KEYS STORED │        │
│   └─────────────┘                   │                 │        │
│                                     └─────────────────┘        │
│   ┌─────────────┐                                              │
│   │ Encrypt     │ ──NOT SENT──────────────────────────────────►│
│   │ Plaintext   │                                              │
│   │ with Key    │                                              │
│   └─────────────┘                                              │
│                                                                │
│   ┌─────────────┐                   ┌─────────────────┐        │
│   │ Send:       │ ──HTTPS─────────► │ Store:          │        │
│   │ • ID        │                   │ • ID            │        │
│   │ • IV        │                   │ • IV            │        │
│   │ • Ciphertext│                   │ • Ciphertext    │        │
│   │ • Metadata  │                   │ • Metadata      │        │
│   └─────────────┘                   │                 │        │
│                                     │  NO PLAINTEXT   │        │
│   ┌─────────────┐                   │  NO PASSWORD    │        │
│   │ Key Stored  │                   │  NO KEY         │        │
│   │ in URL:     │                   │                 │        │
│   │             │                   └─────────────────┘        │
│   │ #id:key   ◄─┘  NEVER in HTTP headers                       │
│   │             │                                              │
│   └─────────────┘  Fragment not sent to server                 │
│                                                                │
└────────────────────────────────────────────────────────────────┘

Technical Specifications

Component	Standard	Parameters
Symmetric Encryption	AES-256-GCM	256-bit key, 96-bit nonce
Key Derivation	PBKDF2	100,000 iterations, SHA-256
Random Generation	CSPRNG	Crypto.getRandomValues()
Key Encoding	Base64URL	URL-safe, no padding
Transport Security	TLS 1.3	Certificate pinning recommended

Encryption Flow

// 1. Key Generation (Browser)
const key = await crypto.subtle.generateKey(
  { name: 'AES-GCM', length: 256 },
  true,
  ['encrypt', 'decrypt']
);

// 2. Encryption (Browser - before network)
const iv = crypto.getRandomValues(new Uint8Array(12));
const ciphertext = await crypto.subtle.encrypt(
  { name: 'AES-GCM', iv },
  key,
  new TextEncoder().encode(plaintext)
);

// 3. Transmission (HTTPS only)
fetch('/api/create', {
  body: JSON.stringify({
    id: randomId,
    encryptedData: { iv: [...iv], data: [...ciphertext] },
    // NO KEY HERE - key stays in browser/URL
  })
});

---

🚀 Installation

System Requirements

Requirement	Minimum	Recommended
PHP	7.4	8.1+
MySQL	5.7	8.0+
Web Server	Apache 2.4	Nginx + Apache
SSL	Required	Let's Encrypt

Step 1: Database Setup

CREATE DATABASE IF NOT EXISTS secure_pastebin
  CHARACTER SET utf8mb4 
  COLLATE utf8mb4_unicode_ci;

USE secure_pastebin;

CREATE TABLE pastes (
    id VARCHAR(32) PRIMARY KEY,
    data TEXT NOT NULL,
    created_at BIGINT NOT NULL,
    expires_at BIGINT NOT NULL,
    burn_after_read TINYINT(1) DEFAULT 0,
    has_password TINYINT(1) DEFAULT 0,
    views INT DEFAULT 0,
    INDEX idx_expires (expires_at)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

Step 2: Configuration

Edit index.php (lines 5-8):

define('DB_HOST', 'localhost');
define('DB_USER', 'your_cpanel_username_dbuser');
define('DB_PASS', 'your_secure_random_password');
define('DB_NAME', 'your_cpanel_username_pastebin');

Step 3: File Upload

/public_html/pastebin/
├── index.php          # API backend + router
├── index.html         # Single-page application
├── style.css          # Complete styling (RTL included)
├── script.js          # Web Crypto implementation
├── .htaccess          # URL rewriting rules
└── database.sql       # Schema (already imported)

Step 4: SSL Enforcement

cPanel Method:

1. SSL/TLS Status → Run AutoSSL
2. Force HTTPS Redirect: ON

Cloudflare Method:

1. DNS proxied through Cloudflare
2. SSL/TLS mode: Full (strict)
3. Always Use HTTPS: ON

Step 5: Verification Checklist

• Database connection successful (check error logs)
• POST /api/create returns 201 with valid JSON
• GET /api/get/{id} returns encrypted data
• Auto-cleanup: Expired rows delete automatically

---

🗄️ Database Structure

Schema Overview

Column	Type	Nullable	Description
id	VARCHAR(32)	NO	Cryptographically random hex
data	TEXT	NO	JSON: {iv: number[], data: number[]}
created_at	BIGINT	NO	Unix timestamp (ms)
expires_at	BIGINT	NO	Auto-deletion trigger (s)
burn_after_read	TINYINT(1)	NO	Boolean flag
has_password	TINYINT(1)	NO	PBKDF2 required flag
views	INT	NO	Access counter

Real-World Example

User Input:

سلام، این پیام محرمانه من است.
Hello, this is my secret message.

What Gets Stored in Database:

{
  "id": "7a3f9e2b8c1d4e5f6a7b8c9d0e1f2a3b",
  "data": "{\"iv\":[187,45,92,201,78,34,156,89,234,12,67,189],\"data\":[45,189,234,67,123,89,45,234,89,123,45,67,234,89,123,45,67,234,89,123,45,67,234,89,123,45,67,234,89,123,45,67,234,89,123,45,67,234,89,123,45,67,234,89,123,45]}",
  "created_at": 1708368000000,
  "expires_at": 1708454400,
  "burn_after_read": 0,
  "has_password": 1,
  "views": 0
}

URL Generated (CONTAINS KEY):

https://yoursite.com/#7a3f9e2b8c1d4e5f6a7b8c9d0e1f2a3b:c2FsdHNhbHRzYWx0:pwd
                                    ↑                    ↑
                              Base64URL salt         Password flag
                              (for PBKDF2)

Critical Security Note:

• The URL fragment (#...) is never sent in HTTP headers
• Server logs contain: GET /api/get/7a3f9e2b8c1d4e5f6a7b8c9d0e1f2a3b
• Server logs never contain: The key, plaintext, or password

---

🔧 API Reference

Authentication

No authentication required. Security through cryptography, not access control.

Endpoints

POST /api/create

Create new encrypted paste.

Headers:

Content-Type: application/json

Request Body:

{
  "id": "a1b2c3d4e5f6... (32 hex characters)",
  "encryptedData": {
    "iv": [12, 34, 56, 78, 90, 12, 34, 56, 78, 90, 12, 34],
    "data": [189, 45, 78, 201, 156, 78, 33, 45, 182, 91, 234, 12, 67]
  },
  "expiresIn": 86400,
  "burnAfterRead": false,
  "hasPassword": false
}

Success Response (201):

{
  "success": true,
  "id": "a1b2c3d4e5f6...",
  "expiresIn": 86400,
  "hasPassword": false,
  "url": "https://yoursite.com/#a1b2c3d4e5f6:base64urlEncodedKey"
}

Error Responses:

Code	Condition	Response
400	Invalid ID format	{"error": "Invalid ID format"}
400	Malformed JSON	{"error": "Invalid JSON"}
400	Missing encryptedData	{"error": "Invalid encrypted data format"}
500	Database failure	{"error": "Failed to save paste"}

GET /api/get/{id}

Retrieve encrypted paste by ID.

Parameters:

Name	Type	Description
id	string	32-character hexadecimal ID

Success Response (200):

{
  "data": {
    "iv": [12, 34, 56, 78, 90, 12, 34, 56, 78, 90, 12, 34],
    "data": [189, 45, 78, 201, 156, 78, 33, 45, 182, 91, 234, 12, 67]
  },
  "burnAfterRead": false,
  "hasPassword": false,
  "created": 1708368000000
}

Error Responses:

Code	Condition
400	Invalid ID format
404	Paste not found or expired

---

🛡️ Security Analysis

Threat Model Matrix

Attacker Capability	Data Access	Mitigation Status
Passive network observer	Encrypted TLS traffic only	✅ Mitigated (TLS 1.3)
Database breach	Ciphertext, metadata only	✅ Mitigated (no keys stored)
Server compromise (root)	Same as database	✅ Mitigated (stateless design)
Backup tape theft	Historical ciphertext	✅ Mitigated (keys not in backups)
URL leak (no password)	Full plaintext	⚠️ User responsibility
URL leak (with password)	Partial (needs password)	⚠️ Reduced risk
Physical device access (post-decrypt)	Plaintext in memory	❌ Not mitigated

What We Protect Against

1. Server-side attacks: Even with full server compromise, attacker gains zero cryptographic material
2. Legal requests: No plaintext or keys to surrender (technical impossibility)
3. Insider threats: System administrators cannot access user content
4. Database leaks: Ciphertext without keys is information-theoretically secure

What We Cannot Protect Against

1. Endpoint compromise: Malware on sender/recipient device
2. Social engineering: Users tricked into sharing URLs
3. Shoulder surfing: Visual observation of decrypted content
4. Forensic analysis: RAM dumps containing decrypted plaintext

Operational Security Recommendations

Risk	Mitigation Strategy
URL in browser history	Use incognito/private mode
URL in cloud sync	Disable browser sync for sensitive operations
Screenshot exposure	Enable "Burn After Read"
Password guessing	Use 12+ character random passwords
Keylogger exposure	Use hardware security keys where possible

---

🌐 Browser Compatibility

Browser	Version	Web Crypto API	Status
Chrome	37+	✅ Full	Recommended
Firefox	34+	✅ Full	Recommended
Safari	7+	✅ Full	Supported
Edge	12+	✅ Full	Supported
Opera	24+	✅ Full	Supported
Internet Explorer	Any	❌ None	Not Supported

Requirement: Secure context (HTTPS or localhost) mandatory for crypto.subtle access.

---

⚖️ Deployment Comparison

Self-Hosted (This Repository) vs Cloudflare Worker

Dimension	Self-Hosted	Cloudflare Worker
Infrastructure	Your server/cPanel	Cloudflare Edge Network
Data Sovereignty	Full control	Third-party processing
Latency	Server location dependent	Global edge (<50ms)
Scalability	Vertical scaling	Auto-scaling
Setup Complexity	Database + SSL required	Zero configuration
Cost	Hosting fees	Free tier generous
Compliance	GDPR/HIPAA self-managed	DPA required
Availability	Your SLA responsibility	99.99% Cloudflare SLA

Recommendation:

• Choose Self-Hosted for: Data sovereignty, compliance requirements, learning
• Choose Cloudflare Worker for: Global reach, zero maintenance, speed

---

🤝 Contributing

Contributions welcome! Areas to improve:

• File attachments (encrypted)
• QR code generation for sharing
• Custom themes
• Browser extension

---

📜 License & Attribution

License: MIT License - See LICENSE

Cryptographic Implementation:

• Web Crypto API W3C Specification
• NIST SP 800-132 (PBKDF2)
• FIPS 197 (AES)

Typography:

• Vazirmatn by Saber Rastikerdar (Persian/Arabic script support)

Inspiration:

• PrivateBin (PHP implementation)
• ZeroBin (original concept)
• CryptPad (collaborative editing)

---

⚠️ Legal Disclaimer

THIS SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND. The authors and contributors assume no liability for data loss, security breaches, or misuse. Users are solely responsible for:

• Key management and storage
• Operational security practices
• Compliance with local laws and regulations
• Secure transmission of URLs and passwords

---

📊 Quick Stats

Metric	Value
Encryption strength	256-bit
Key derivation iterations	100,000
IV length	96-bit (12 bytes)
Maximum message size	Limited by browser memory (~2GB)
Supported languages	All Unicode (UTF-8)
Database overhead	~2x plaintext size (JSON + Base64)

---

👤 Author

TheGreatAzizi

• GitHub: @TheGreatAzizi
• X/Twitter: @the_azzi