secure-instructions
Secure Instructions
A self-contained, offline-capable application for creating and distributing encrypted instructions and files. Access requires a consensus of multiple parties, using Shamir’s Secret Sharing.
Overview
This tool allows you to create sensitive content (text instructions and file attachments) that is encrypted using a master key. The master key is then split into multiple “shares” (passwords). To decrypt the content, a specified number of these shares must be combined.
Key Features:
- Offline First: The generated HTML file works entirely offline. No data is sent to any server.
- Self-Contained: The application, logic, and encrypted data are all contained within a single HTML file.
- Multi-Party Authorization: Utilize Shamir’s Secret Sharing to require multiple people to agree (by providing their password share) before the content can be viewed.
- Secure: Uses AES-GCM encryption for content and Shamir’s Secret Sharing for key management.
- File Support: Attach files which are also encrypted and embedded directly into the HTML.
Manual
This application is designed to be easy to use. The following guide walks you through creating and accessing secured content.
1. Creating Content (Admin)
To create new content, open secure-instructions.html in your browser. Navigating to the admin interface (usually by appending #admin to the URL or using a provided link) allows you to manage content.
Click “Create Content” to begin.
- Enter Details: Provide a name and description for your content.
- Define Security: Set the “Total Number of Password Shares” and the “Required Shares to Decrypt”. For example, you can generate 5 shares but require only 3 to decrypt.
- Generate Shares: Click “Generate Shares”. The system will create the requested number of password shares.
- IMPORTANT: Distribute these shares to the intended recipients immediately. The system does not store them for you.
- Master Key: A master key is also provided for emergency recovery if needed.
- Add Content: Enter the secret instruction text and upload any files you wish to secure.
- Save: Click “Save Content” to encrypt and embed the data into the application.
2. Distributing the Application
Once content is saved, the secure-instructions.html file now contains the encrypted data. You can distribute this single file to all parties (e.g., via email, USB drive, or shared network location).
Note: Ensure you have distributed the password shares securely to the respective key holders.
3. Accessing Content
To view the content, users open the secure-instructions.html file. They will see the list of available encrypted items.
- Select Content: Click “Access Content” for the item you wish to view.
- Enter Shares: The system will prompt for the required number of password shares.
- Decrypt: Once the valid shares are entered, click “Decrypt Content”. The instructions and files will be revealed.
License and Credits
This project is licensed under the MIT License.
This application includes the secrets.js library by amper5and (Alexander Stetsyuk) and others, which implements Shamir’s Secret Sharing.
secrets.js is licensed under the MIT License:
Copyright (c) 2014 Alexander Stetsyuk
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.