Cryptochat

Cryptochat is a fully-featured end-to-end encrypted realtime chat application built using NodeJS, React, and WebSockets.

This project was created by:

• Lukas Romsicki
• Khaled Mohamed
• Robert Irwin

Features

• End-to-end encryption of all messages using 256-bit AES.
• Symmetric key exchange using 4096-bit RSA-OAEP hashed using SHA-256.
• Realtime communication via WebSockets.
• Group communication with infinitely many users.
• JSON Web Token authentication.
• Local private key storage with *.pem files.
• Persisted conversations and messages (still encrypted).
• Client app is hosted by the server application for unified deployment. Encryption/decryption/key generation remains solely available in the client app, with no unencrypted data exchange with the server.

Technology stack

• TypeScript as a language of choice with Sass.
• WebCrypto API in the browser for accelerated key generation, encryption, and decryption.
• JSON Web Tokens as a form of authentication.
• ReactJS for front-end client application.
• NextJS application architecture framework. Also provides server-side rendering of the client app.
• socket.io for realtime messaging and communication.
• Express server backbone.
• NodeJS version 15.10.0.
• TypeORM as a database management interface from the server.
• PostgreSQL as a database management system.

Installation

Note: Most versions of NodeJS since v10 should work.

Note: These instructions mostly assume that the project is being run on a macOS or Linux platform.

There are a few prerequisites that must be met in order for the application to launch. Firstly, the PostgreSQL server must be up and running.

On macOS, you can use Homebrew to install PostgreSQL. Ideally, do not provide a password for the default superuser role.

brew install postgresql
brew services start postgresql

On Windows, you will need to install PostgreSQL from the website manually, and install it. Note that some of the yarn db:xx commands may not work on Windows, depending on how you've installed PostgreSQL.

Next, create a file called .env in the root of this project. This file contains the environment variables. In order for JSON Web Token signing to work, a signing secret must be established on the server. To generate a random secret, execute the following:

node -e "console.log(require('crypto').randomBytes(256).toString('base64'));"

You can then copy this value and paste it into the .env file, replacing <my_secret> with the secret you copied:

TOKEN_SECRET=<my_secret>

Then, once in the project directory, run the following to set up the dependencies and migrate the database:

yarn install
yarn db:setup

Note: If you have a pre-existing PostgreSQL installation, you should run yarn db:reset to ensure that there are no conflicts between role names and database names.

After the above commands succeed, you can build and start the application in production mode by issuing the following command:

yarn build
yarn start:prod

Congratulations! You can now access the application at http://localhost:3000.

Development

During development, you may wish to make use of hot module reloading, in which case you can use the following command to start the server instead:

yarn start:dev

Available commands

• yarn start:dev - Starts the app in development mode.
• yarn start:prod - Starts the app in production mode.
• yarn build - Builds the JavaScript bundles for production.
• yarn db:user:create - Creates the database user.
• yarn db:create - Creates the database.
• yarn db:migrate - Runs the migrations.
• yarn db:setup - Configures the database and user from scratch.
• yarn db:drop - Drops the database and user.
• yarn db:reset - Drops and recreates the database and user, and migrates the database.

Screenshots