encryptron

A fun CLI for "encrypting" sneaky messages.

Synopsis

This was a project I made with my friends for fun. We were writing simple python scripts to "encrypt" our messages and hide it from one another on Discord. I came across this site which has a list of Unicode empty characters. The list had 16 different invisible characters, so I thought "why not encode Ascii characters into pairs of unicode space characters?" and that is what we did. After writing up the script, we met a roadblock: one of the sixteen whitespace characters, U+00A0, the no-break space is converted into regular spaces by Discord, presumably to prevent website/domain name fraud. The fix was pretty easy, we just had to find another unicode character to replace it. We found the invisible comma/separator U+2063 and the empty Braille pattern U+2800, and decided to go with the former.

While making the project, I wondered if I could make an accompanied "CLI" to make the script easier to use. The organization of this project is a little messy, but it's just a proof of concept. The CLI works like any other executable (using argparse), but it also has a terminal mode, in which a "terminal" is loaded up that uses a non-shell and more specific/efficient syntax. The mechanisms of the Encryptron are mostly explained by its own terminal's help file. One other thing to note is that I use the term crypt to mean encrypted text throughout the documentation because I didn't want to have to type the latter a lot. Almost all of the ASCII Art used were generated using this site.

During this project I had the opportunity to mess with Disk Images on MacOS (you'll see when you download the installer), and I also had fun messing with ANSI escapes, which culminated in an unrelated file in this repository called minecraft 🤣.

I think the real value (if any) of this project, other than the fun and learning experience, is the stuff in encryptron/codec.py. If you have any ideas about improving it, go right ahead! I'll be very happy about pull requests of any type.

Packaging

While there is a proper way to distribute python packages and apps, the Encryptron is very small and only uses one non-default (i.e. not shipped with python) package optionally for its terminal: pyperclip, so I've decided to resort to writing a simple install script that just checks if there exists a python 3 installation that is newer than 3.6 and then copies everything to a directory (hopefully without requiring admin privileges), and after that, creating a symlink from the main script crypt to /usr/local/bin/script. The main script sets up PYTHONPATH so the and calls main.py so the program can function normally. The README.txt file in this repository is for the disk image.

The target directory is ~/.config/encryptron be default, since most users have a ~/.config directory, it wouldn't bother the user too much (and the install script has write permissions there without requiring the user password.) The target directory is stored in packaging/package_settings.sh, which is copied into the .scripts folder of the disk image by the package preparation script packaging/package.sh.

I packaged all this into a MacOS Disk Image. With minor modifications this should also work on any Linux distribution. Compatibility with Windows is beyond the scope of this project, but I suppose that all features except for the terminal should be able to run on Windows. The packaging process for future updates is streamlined by the packaging/package.sh script. A list of files (scripts, assets, and installation helper files) to be moved into the Disk Image (except install and README.txt which are selected by default) are stored in packaging/package_settings.sh, which is used and put into .scripts on the Disk Image by packaging/package.sh and then used by install during the user-end installation.

The file structure of the Disk Image is as follows:

• The install script
• The README.txt file
• The .assets directory containing art/icons (and background image) for the install drive
• The .scripts directory containing all the scripts to be installed.
  • There is a special subfolder called helper containing scripts that will only be used during the installation process. This is mostly so that I don't mix up which scripts I need to copy.
• And the .fseventsd directory because MacOS loves it so much

How to package

After populating a folder with the necessary scripts, use the Disk Utility app to create a read/write drive from that folder. Then, modify the folder stylistically, and after that, go back to Disk Utility and convert the drive to a read-only drive.

Update: Packaging has now been made easier with the advent of a new packaging script packaging/package.sh that largely automates the packaging process. This makes it easier to package updates.

Basic Version Control

The only locations in which the version number is present are

• At the top of main.py
• At the top of install
• And in README.txt

TODOS

• Add style to the help and tutorial docs using ANSI escape codes.
• Fix issue with up/down arrows. (info: interactive mode seems to be a potential fix.)
• Get Config up and working. Customization will be implemented gradually.
• !!! Write installation/packaging scripts.