Shield - File Encryption & Decryption in your Project

Under the Apache-2.0 License, Shield is a utility for encrypting and decrypting files in your project. It uses AES-256 encryption via the openssl command line tool.

Table of Contents

1. Downloading and Installing Shield
2. Self-installation
3. User Requirements
4. Setup
5. Flags/Options
6. Usage
7. Running Shield with Docker
8. Developer Guide
9. Note
10. Warning
11. Disclaimer

Downloading and Installing Shield

Shield can be easily installed on macOS, Linux, and Windows. Choose the script appropriate for your operating system and execute it in your terminal to download and install the latest version of Shield:

macOS/Linux:

curl -sSL https://raw.githubusercontent.com/shyce/shield/main/install.sh | bash

Optionally, you can specify a particular version to install like this:

curl -sSL https://raw.githubusercontent.com/shyce/shield/main/install.sh | bash -s -- -v <version>

Replace <version> with the version number that you want to install.

Windows:

On Windows, open a PowerShell window and run the following command:

Set-ExecutionPolicy RemoteSigned
iwr -useb https://raw.githubusercontent.com/shyce/shield/main/install.ps1 | iex

Optionally, you can specify a particular version to install like this:

Set-ExecutionPolicy RemoteSigned
iwr -useb https://raw.githubusercontent.com/shyce/shield/main/install.ps1 | iex -v <version>

Replace <version> with the version number that you want to install.

Self-installation

Shield provides a self-installation feature for users who already have the binary. This functionality can be triggered using the --install flag. When the --install flag is passed, Shield will attempt to copy its binary to a system-wide location, making it available from any directory in your terminal. This can be especially helpful when working with multiple projects that all utilize Shield.

To use this feature, navigate to the directory where the Shield binary is located and run the following command:

./shield --install

The binary will then be copied to the appropriate system-wide location, depending on your operating system.

After successful installation, you should be able to run Shield from any directory by just typing shield followed by the desired flags.

Please ensure you have the necessary permissions to write to the target directory. On Unix-based systems, you may need to prepend the command with sudo if you encounter permission issues.

User Requirements

Shield relies on a few external tools to operate. These include:

• OpenSSL: Required for AES-256 encryption and decryption. Please ensure it is installed and accessible in your system's PATH.

• Git (optional): If you want to make use of Shield's Git integration features, such as the pre-commit hook, Git must be installed and accessible in your system's PATH.

OpenSSL Installation

macOS

brew install openssl

Ubuntu/RHEL

Ubuntu:

sudo apt-get install openssl

RHEL:

sudo yum install openssl

Git Installation

macOS

brew install git

Ubuntu/RHEL

Ubuntu:

sudo apt-get install git

RHEL:

sudo yum install git

Setup

1. Create a ~/.ssh/vault file with a secure password and chmod 600 ~/.ssh/vault. This is used to encrypt and decrypt files in the repository and should be shared between developers of your project.

2. Create a .shield file at the root of your project. This file will list all the glob patterns for files you want to encrypt. Each pattern should be on a new line. For example:

   *.secret
   **/secrets/*.txt
   secrets/**/*.pem
   

   The above patterns will match:

   • Any file with the .secret extension in the root directory.
   • Any .txt file in any secrets directory at any level.
   • Any .pem file in any directory or sub-directory under a root-level secrets directory.

3. Create a .shieldignore file at the root of your project. This file will list all the glob patterns for files you want to exclude from encryption. Each pattern should be on a new line. This is useful for ignoring certain files or directories. For example:

   test/*
   temp.secret
   **/vendors/**
   

   The above patterns will ignore:

   • Any files in the test directory in the root of your project.
   • The temp.secret file in the root directory.
   • Any files in any vendors directory at any level.

4. Generate a pre-commit hook in your project with shield -g

Flags/Options

Shield accepts a number of options that can be passed at the command line:

• -v <path>: Specify the directory to operate on. Default is the current directory.

  Example: shield -v /path/to/my/project

• -e: Encrypt files. This will encrypt all files that match the patterns in your .shield file and do not match any patterns in your .shieldignore file.

  Example: shield -e

• -d: Decrypt files. This will decrypt all encrypted files that match the patterns in your .shield file and do not match any patterns in your .shieldignore file.

  Example: shield -d

• -g: Generate Git pre-commit hook. After running this command, every time you try to commit, the hook will check for unencrypted files and encrypt them.

  Example: shield -g

• --scan: Scan git-diff files for unencrypted files. This flag will perform a scan operation that identifies unencrypted files in your git-diff.

  Example: shield --scan

• --version: Print version information. This flag will output the current version of the shield tool you are using.

  Example: shield --version

• --install: Install Shield. This will copy the current binary to your local user PATH which allows you to use the shield command anywhere on your system.

  Example: shield --install

• --passwordFile <path>: Specify the password location. Default location is ~/.ssh/vault.

  Example: shield --passwordFile /path/to/my/password/file

Use these flags in combination to perform the tasks you need. For instance, to encrypt files in a specific directory, you might run shield -e -v /path/to/my/project.

For displaying the usage details, simply run shield without any flags. The tool will provide a brief explanation about each flag.

shield

Usage

• To encrypt files, run the command: shield -e. This will encrypt all files that match the patterns in your .shield file and do not match any patterns in your .shieldignore file.

• To decrypt files, run the command: shield -d. This will decrypt all encrypted files that match the patterns in your .shield file and do not match any patterns in your .shieldignore file.

• To generate a git pre-commit hook that checks for unencrypted files (from the .shield patterns) and encrypts them, run the command: shield -g. After running this command, every time you try to commit, the hook will check for unencrypted files and encrypt them.

Running Shield with Docker

Shield can be run inside a Docker container without installing anything else on your system. The included docker.sh script will handle building and running the Docker container for you.

Before running the docker.sh script, ensure you have Docker installed and running on your system.

1. Make sure the docker.sh script is executable. If it's not, you can make it executable by running chmod +x docker.sh.

2. Run the docker.sh script:

   ./docker.sh

   This script will ask you to enter the directory you want to mount inside the Docker container. This should be the directory containing the files you want to encrypt or decrypt with Shield.

   The script will automatically build the Shield Docker image and then run it, mounting the specified directory and your vault file inside the Docker container. This means you can run Shield inside the Docker container just like you would if it was installed directly on your system.

Note: This Docker container runs as the current user on your system and mounts your vault file and the specified directory, so it will be able to read and write files in the mounted directory and read your vault file.

Developer Guide

Developer Requirements

• jq
• openssl
• git-chglog
• Go (version 1.16 or newer)

Before you can build or version Shield, please ensure that the above tools are installed.

Installation

jq

---

macOS

brew install jq

Ubuntu/RHEL

Ubuntu:

sudo apt-get install jq

RHEL:

sudo yum install jq

OpenSSL

---

macOS

brew install openssl

Ubuntu/RHEL

Ubuntu:

sudo apt-get install openssl

RHEL:

sudo yum install openssl

git-chglog

---

go install github.com/git-chglog/git-chglog/cmd/git-chglog@latest

Go

---

Download the latest Go package from here and follow the installation instructions.

Building the Project

To build the shield utility, run the build.sh script at the root of the project:

./build.sh

This script reads version information from version.json, builds the Go project with these details, and places the resulting binary in the root of the project.

Versioning

To bump up the version of the project, run the version.sh script with the relevant arguments:

./version.sh <major|minor|patch>

This will increment the specified version part by one. For example, if the current version is 1.2.3, running ./version.sh patch will change the version to 1.2.4.

The version changes are reflected in version.json file.

Note

The encrypted files are prefixed with a specific tag "SHIELD[1.0]:" to help recognize them. The encryption and decryption processes are managed by OpenSSL. If you encounter any issues, make sure OpenSSL is correctly installed and the path is set.

Warning

• This is a basic implementation and might not cover all use cases or error scenarios.
• Be cautious while using it for production. Test thoroughly to ensure it meets your requirements.
• Be aware that if the encryption process is interrupted or fails, it could leave behind unencrypted data or corrupt your files. Always backup your data.

Disclaimer

Use this tool at your own risk. The author is not responsible for any data loss or damage.