December 14, 2018

446 words 3 mins read



Password protect a static HTML page

repo name robinmoisson/staticrypt
repo link
language JavaScript
size (curr.) 213 kB
stars (curr.) 1941
created 2017-04-29
license MIT License


Based on the crypto-js library, StatiCrypt uses AES-256 to encrypt your string with your passphrase in your browser (client side).

Download your encrypted string in a HTML page with a password prompt you can upload anywhere (see example).

You can encrypt a file online at


Disclaimer if you have extra sensitive banking data you should probably use something else!

StatiCrypt generates a static, password protected page that can be decrypted in-browser: just send or upload the generated page to a place serving static content (github pages, for example) and you’re done: the javascript will prompt users for password, decrypt the page and load your HTML.

It basically encrypts your page and puts everything with a user-friendly way to use a password in the new file.

AES-256 is state of the art but brute-force/dictionary attacks would be trivial to do at a really fast pace: use a long, unusual passphrase.

The concept is simple but I am not a cryptographer, feel free to contribute or report any thought to the GitHub project! (Though be warned it might take me a long time to get to it - I apologize in advance)

Similar project: MaxLaumeister/clientside-html-password


Staticrypt is available through npm as a CLI, install with npm install -g staticrypt and use as follow:

Usage: staticrypt <filename> <passphrase> [options]

  --help               Show help                                       [boolean]
  --version            Show version number                             [boolean]
  -e, --embed          Whether or not to embed crypto-js in the page (or use an
                       external CDN)                   [boolean] [default: true]
  -o, --output         File name / path for generated encrypted file
                                                        [string] [default: null]
  -t, --title          Title for output HTML page
                                            [string] [default: "Protected Page"]
  -i, --instructions   Special instructions to display to the user.
                                                        [string] [default: null]
  -f, --file-template  Path to custom HTML template with password prompt.
                          [string] [default: "[...]/cli/password_template.html"]

Example usages:

  • staticrypt test.html mysecretpassword -> creates a test_encrypted.html file
  • find . -type f -name "*.html" -exec staticrypt {} mypassword \; -> create encrypted files for all HTML files in your directory

You can use a custom template for the password prompt - just copy cli/password_template.html and modify it to suit your presentation style and point to your template file with the -f flag. Be careful to not break the encrypting javascript part, the variables replaced by staticrypt are between curly brackets: {instructions}.

ADBLOCKERS: If you do not embed crypto-js and serve it from a CDN, some adblockers see the crypto-js.min.js, think that’s a crypto miner and block it.

Thanks Aaron Coplan for bringing the CLI to life!

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