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Locked HTML File
Lock a file or note inside a single HTML page that opens in any browser with your password, no app needed.
Free, no uploads, no sign-up. Runs 100% in your browser.
How Locked HTML File works
Everything happens in your browser with the Web Crypto API and plain JavaScript. Nothing is uploaded, so the files and passwords never leave this device. The file is encrypted with AES-256-GCM using a key from your password (PBKDF2, 250,000 rounds). The HTML page carries a few lines of script that ask for the password and decrypt it with the browser.
Input: Any file, Text. Output: HTML.
How to use Locked HTML File
- Choose a file or write a note.
- Set a page title and a password.
- Press Make locked HTML and download it.
- Send the file, and send the password another way.
Tips
- Nothing is uploaded, so you can use these tools on sensitive files.
- Share passwords a different way than the file itself.
- Always check a cleaned or redacted file before you send it.
Locked HTML File FAQ
- Are my files uploaded?
- No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.
- Is it free? Are there limits or watermarks?
- Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.
- Does it work offline?
- Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.
Related tools
- Encrypt / Decrypt Text & Files: Password-protect text or any file with AES-256-GCM, ChaCha20-Poly1305 or OpenSSL-compatible AES.
- Password ZIP: Make an AES-256 password-protected ZIP that opens anywhere, or unlock one you have the password for.
- Steganography: Hide a secret message or small file inside an image, with an optional password, and reveal it later.
- Metadata Scrubber: Remove hidden data from photos, PDFs, Office files and MP3s in one batch: GPS, camera, author, company and more.