# 🔐 Secure Pastebin (Self-Hosted) > **Self-hosted, zero-knowledge, end-to-end encrypted pastebin built with PHP, MySQL, Web Crypto API, and a responsive single-page UI.** Share sensitive text securely. Encryption happens in the browser before upload, the server stores ciphertext only, and the decryption key stays in the URL fragment (`#...`) so it is never sent to the server. [](https://opensource.org/licenses/MIT) [](https://php.net) [](https://en.wikipedia.org/wiki/Galois/Counter_Mode) [](#installation) [](#api) 🌐 **Live Demo:** https://sphost.theazizi.ir ☁️ **Cloudflare Worker version:** https://github.com/TheGreatAzizi/Secure-Pastebin-Cloudflare-Worker --- ## ✨ Features - 🔒 **Client-side AES-256-GCM encryption** using the native Web Crypto API - 🛡️ **Zero-knowledge architecture** — server never receives plaintext, password, or key - 🧾 **Optional subject field** included inside the encrypted payload - 🔑 **Optional password protection** with PBKDF2 (100,000 iterations, SHA-256) - 🔥 **Burn after reading** support - ⏱️ **Preset expiration** plus **custom expiration date & time** - 📝 **Markdown authoring + rendering** - compact formatting toolbar in the composer - Markdown is rendered **after decryption only** - 🔗 **Two share-link formats** - full link: `/p/{id}#key` - short link: `/#id:key` - 📋 **Copy actions** for full link, short link, and decrypted text - 📱 **Responsive UI** with improved mobile layout - 🌍 **RTL-aware text handling** for Persian / Arabic / Hebrew content - 🔤 **No external font CDN** — uses a local Vazirmatn-based font stack - ⚙️ **Documented HTTP API** with `/api/docs` --- ## 🔐 How the security model works 1. The browser generates or derives the encryption key locally. 2. The browser encrypts the payload locally using AES-256-GCM. 3. The server receives only: - paste ID - IV - ciphertext - metadata such as expiration / burn-after-read / password flag 4. The decryption key is kept in the URL fragment (`#...`). URL fragments are not sent in normal HTTP requests. 5. The recipient opens the link, downloads the encrypted payload, and decrypts it locally. ### Important note If the full share URL is lost, the message is **not recoverable**. The server cannot reconstruct the decryption key. --- ## 🧱 Current stack - **Frontend:** HTML, CSS, vanilla JavaScript - **Crypto:** Web Crypto API - **Backend/router:** PHP - **Database:** MySQL / MariaDB - **Storage model:** encrypted payload + metadata only --- ## 🆕 What is included in this version Compared with the older README, the current app now includes compact share links, custom expiration timestamps, a Markdown toolbar and renderer, password strength feedback, an API docs page, updated responsive layout, and a local-font setup with no external font dependency. The older README you uploaded still documents the earlier API shape and older sharing format. fileciteturn0file0 --- ## 🧩 Share link formats ### Full share link ```text https://your-domain.com/p/AbCdEf1234567890#BASE64URL_KEY ``` ### Full share link with password flag ```text https://your-domain.com/p/AbCdEf1234567890#BASE64URL_SALT:pwd ``` ### Short share link ```text https://your-domain.com/#AbCdEf1234567890:BASE64URL_KEY ``` ### Short share link with password flag ```text https://your-domain.com/#AbCdEf1234567890:BASE64URL_SALT:pwd ``` ### ID compatibility The backend currently accepts these ID formats: - legacy **32-character lowercase hex** IDs - compact **16-character URL-safe IDs** (`[A-Za-z0-9_-]{16}`) The UI currently generates the compact 16-character format by default. --- ## 📝 Encrypted payload format The browser encrypts a JSON payload. Subject and content are both inside the encrypted blob. Example logical structure before encryption: ```json { "subject": "Optional subject", "content": "Secret message with **Markdown** support" } ``` The server never sees this plaintext object. --- ## 🚀 Installation ## 1) Database Create a database, then import `database.sql`. ```sql CREATE TABLE IF NOT EXISTS 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 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci; CREATE INDEX idx_expires ON pastes(expires_at); ``` ## 2) Configure PHP Edit the database constants in `index.php`: ```php const DB_HOST = 'localhost'; const DB_USER = 'your_db_user'; const DB_PASS = 'your_db_password'; const DB_NAME = 'your_db_name'; ``` ## 3) Upload files Upload the project files to your web root. ```text /public_html/ ├── .htaccess ├── api-docs.php ├── database.sql ├── index.html ├── index.php ├── LICENSE ├── README.md ├── script.js └── style.css ``` ## 4) Enable URL rewriting Apache `.htaccess` used by the project: ```apache RewriteEngine On RewriteBase / RewriteCond %{REQUEST_FILENAME} -f [OR] RewriteCond %{REQUEST_FILENAME} -d RewriteRule ^ - [L] RewriteRule ^ index.php [L] ``` ## 5) Use HTTPS `crypto.subtle` requires a secure context in production. Use: - HTTPS on your domain, or - `localhost` during local development --- ## 📁 Project structure | File | Purpose | |------|---------| | `index.php` | router + API backend | | `index.html` | single-page app UI | | `script.js` | encryption, decryption, UI behavior, Markdown tools | | `style.css` | responsive styling | | `api-docs.php` | human-friendly API documentation page | | `database.sql` | MySQL schema | | `.htaccess` | Apache rewrite rules | --- ## 🧠 Composer UI highlights ### Secure message composer - optional subject - Markdown toolbar - multiline textarea - preset expiration dropdown - custom expiration datetime picker - password-protection toggle - burn-after-reading toggle - password strength meter ### Decrypted result view - subject display - rendered Markdown output - copy decrypted text button - burn-after-read warning when applicable --- ## ✍️ Markdown support Markdown is stored as plain text inside the encrypted payload and is rendered only after decryption. Supported authoring helpers include: - **Bold** - *Italic* - ~~Strikethrough~~ - headings - quotes - bullet lists - numbered lists - links - inline code - fenced code blocks This keeps the stored payload simple while still giving the recipient a readable result view. --- ## 🔌 API ### Docs page Once deployed, the built-in docs page is available at: ```text https://your-domain.com/api/docs ``` ### Base notes - API stores **ciphertext only** - API does **not** perform encryption for you - client must encrypt before sending data - password or raw key must **never** be sent to the server ### Endpoints | Method | Route | Description | |--------|-------|-------------| | `GET` | `/api/health` | service health check | | `GET` | `/api/options` | API capabilities, limits, routes | | `GET` | `/api/docs` | HTML API documentation | | `POST` | `/api/pastes` | create a paste | | `POST` | `/api/pastes/{id}` | create a paste with a specific ID | | `GET` | `/api/pastes/{id}` | fetch encrypted payload | | `GET` | `/api/pastes/{id}/meta` | fetch metadata only | | `POST` | `/api/create` | legacy create route | | `GET` | `/api/get/{id}` | legacy read route | ### Limits From the current backend: - minimum expiration: **300 seconds** - maximum expiration: **31536000 seconds** (365 days) - max encrypted payload size: **4 MiB** ### Supported create payload formats You can create a paste using any of these shapes: 1. nested byte arrays ```json { "encryptedData": { "iv": [12, 34, 56], "data": [99, 88, 77] } } ``` 2. top-level byte arrays ```json { "iv": [12, 34, 56], "data": [99, 88, 77] } ``` 3. nested base64url strings ```json { "encryptedData": { "ivBase64": "AAECAwQFBgcICQoL", "dataBase64": "mYh3" } } ``` 4. top-level base64url strings ```json { "ivBase64": "AAECAwQFBgcICQoL", "dataBase64": "mYh3" } ``` `ivBase64url` / `dataBase64url` are also accepted. ### Create request fields | Field | Required | Description | |------|----------|-------------| | `id` | optional | custom paste ID | | `encryptedData` or equivalent | yes | ciphertext payload | | `expiresIn` | optional | expiry in seconds | | `customExpiresAt` | optional | exact Unix timestamp in seconds | | `burnAfterRead` | optional | delete after first successful read | | `hasPassword` | optional | indicates password is required on the client | If `customExpiresAt` is present, it overrides `expiresIn`. ### Example: create a paste ```bash curl -X POST https://your-domain.com/api/pastes \ -H "Content-Type: application/json" \ -d '{ "id": "AbCdEf1234567890", "encryptedData": { "iv": [12, 34, 56, 78, 90, 12, 34, 56, 78, 90, 12, 34], "data": [189, 45, 78, 201, 156, 78, 33, 45] }, "expiresIn": 86400, "burnAfterRead": false, "hasPassword": false }' ``` ### Example success response ```json { "success": true, "apiVersion": "1.2", "id": "AbCdEf1234567890", "expiresAt": 1735689600, "expiresIn": 86400, "burnAfterRead": false, "hasPassword": false, "url": "https://your-domain.com/p/AbCdEf1234567890", "retrieveUrl": "https://your-domain.com/api/pastes/AbCdEf1234567890", "metaUrl": "https://your-domain.com/api/pastes/AbCdEf1234567890/meta", "docsUrl": "https://your-domain.com/api/docs" } ``` ### Example: fetch encrypted payload ```bash curl https://your-domain.com/api/pastes/AbCdEf1234567890 ``` Example response: ```json { "success": true, "apiVersion": "1.2", "id": "AbCdEf1234567890", "encryptedData": { "iv": [12, 34, 56, 78, 90, 12, 34, 56, 78, 90, 12, 34], "data": [189, 45, 78, 201, 156, 78, 33, 45], "ivBase64": "AAECAwQFBgcICQoL", "dataBase64": "mYh3" }, "data": { "iv": [12, 34, 56, 78, 90, 12, 34, 56, 78, 90, 12, 34], "data": [189, 45, 78, 201, 156, 78, 33, 45] }, "burnAfterRead": false, "hasPassword": false, "created": 1735603200000, "expiresAt": 1735689600, "views": 1 } ``` ### Burn-after-read behavior When `burnAfterRead` is enabled, the first successful fetch from `GET /api/pastes/{id}` returns the ciphertext and then removes that paste from storage. ### Metadata endpoint ```bash curl https://your-domain.com/api/pastes/AbCdEf1234567890/meta ``` Example response: ```json { "success": true, "apiVersion": "1.2", "id": "AbCdEf1234567890", "shareUrl": "https://your-domain.com/p/AbCdEf1234567890", "retrieveUrl": "https://your-domain.com/api/pastes/AbCdEf1234567890", "created": 1735603200000, "expiresAt": 1735689600, "remainingSeconds": 86400, "burnAfterRead": false, "hasPassword": false, "views": 0 } ``` --- ## 🧪 Health and options ### Health ```bash curl https://your-domain.com/api/health ``` ### Options ```bash curl https://your-domain.com/api/options ``` `/api/options` returns API version, limits, presets, capabilities, endpoints, and notes. --- ## 🌐 Browser compatibility | Browser | Status | |---------|--------| | Chrome / Edge | ✅ | | Firefox | ✅ | | Safari | ✅ | | Internet Explorer | ❌ | A secure context is required for the Web Crypto API. --- ## 🛡️ Security notes ### Protected well - database leaks still expose ciphertext only - server admins do not have plaintext or keys - password material stays client-side - URL fragment is not sent to the backend ### Not protected well - malware on sender or recipient device - leaked full share URLs - weak passwords chosen by users - copied plaintext after decryption - screenshots or shoulder surfing ### Recommended operational practices - send password separately from the URL - use burn-after-read for highly sensitive messages - prefer long random passwords - use private browsing on shared devices - do not paste highly sensitive links into third-party chatbots or analytics tools --- ## 🎨 UX and design notes - improved composer layout for desktop and mobile - cleaner stacked settings cards for expiration and security options - compact Markdown toolbar - icon-only social links in the footer - consistent visual style shared by the app and API docs page --- ## 📌 Roadmap ideas - encrypted file attachments - QR code for secure links - separate key-sharing mode - OpenAPI / Swagger export - admin-only cleanup / moderation tools - theme switcher --- ## 🤝 Contributing Issues and pull requests are welcome. If you open a PR, try to keep these guarantees intact: - client-side encryption only - zero-knowledge storage model - no accidental leakage of key material to the server - backward compatibility for existing shared links where possible --- ## 📜 License MIT — see [`LICENSE`](LICENSE). --- ## 👤 Author **TheGreatAzizi** - GitHub: [@TheGreatAzizi](https://github.com/TheGreatAzizi) - X: [@the_azzi](https://x.com/the_azzi) - Telegram: [@luluch_code](https://t.me/luluch_code) --- ## ⚠️ Disclaimer This project is provided **as is** without warranty of any kind. You are responsible for your own deployment security, backups, SSL/TLS configuration, database hardening, and safe sharing of URLs and passwords.