Cryptboard.io allows to send text messages and files between multiple devices
Website: https://cryptboard.io/
Why would I need it?
- To copy and paste text/files between Host and Virtual machine where clipboard not supported
- To copy and paste text/files into Remote Desktop, such as VMWare Horizon, RDP, and others where clipboard doesn’t work or disabled
- To send valuable data such as passwords or some security keys and tokens without danger of it being intercepted
- To exchange information in a hostile environment where the server could be evil and yet not giving it a chance to decrypt messages
- Doing all this stuff without the need for registration
Features
- Anonymous authorization on the server without the need for registration
- Hybrid RSA+AES encryption of data with asymmetric keys stored on client
- All sent data encrypted on the client and could not be decrypted by the server
- Clients adding each other to the “receivers list” by sending their public key and user ID using third-party channel
- Possible to add public key and user ID by scanning QR-code
- Single button click to clear all client’s data and keys and start a new session
Disclaimers
- Application is on its beta stage so some bugs could be out where
- Application is written initially for my own use so code isn’t perfect and would be refactored later
- Design and all the frontend is made by a backend programmer, so it could look quite ugly
Usage of the official app
- After you opening https://cryptboard.io/ on any device, it automatically authorizes on the server and gets a user ID (uid)
- Also, private and public RSA keys are generated to use in the encryption/decryption process
- To start exchange text or files you have to share your uid and public key with another user (or device)
- You can open QR-code on the “Share key” page with your mobile phone, and do “Add Key” from it
- If you open two such QR-codes from the same mobile phone, and use the checkbox “Share all my receivers” (by default turned on on mobile), all of the keys would be shared between devices and your mobile phone
- You can copy the link on the “Share key” page and send it over some other messenger or email
- Also, you can copy QR code (make a screenshot) and send it over other messenger or email
- Device where your uid and the public key is added could automatically send its uid and public key back encrypted if the checkbox “Send my key back” is checked (by default it is)
- After uid and key is added you can send text or files back and forth between devices (or people)
- Avatars should be used to check if uid and the public key wasn’t changed while traveling through third-party messenger
Details on secure usage could be found at https://cryptboard.io/security
Technologies
- Application backend is based on php-fpm, with super-simple hand-crafted micro-framework
- Database used by backend server is Redis
- Frontend is written on html + css + vanillaJs + jQuery + Bootstrap
Detail on used technologies can be seen here: https://cryptboard.io/about
Deploying your own installation
Docker installation
Prerequisites:
- Docker
- docker-compose
- Nginx on the host machine
Installation:
- Clone repo.
git clone git@github.com:MihanEntalpo/cryptboard.io.git
- Install docker and docker-compose
Installation of docker described at https://docs.docker.com/get-docker/
Installation of docker-compose described at https://docs.docker.com/compose/install/
- Create config file
cp web-app/.env.docker.example web-app/.env.docker
- Generate public and private keys for usage with JWT:
Run command:
ssh-keygen -t rsa -b 4096 -m PEM -f jwtRS256.key
# Don't add passphrase
openssl rsa -in jwtRS256.key -pubout -outform PEM -out jwtRS256.key.pub
Files jwtRS256.key and jwtRS256.key.pub would be created.
- Put contents of the files to .env.docker
Content of the files should be put in one-liners with “n” string joining splitted lines, and put it to JWT_PUBLIC_KEY and JWT_PRIVATE_KEY variables.
To make it simple just run the following bash command:
Fill JWT_PRIVATE_KEY in .env.docker:
LINE=$(cat ./web-app/jwtRS256.key | tr 'n' '$' | sed 's|$|\\n|g;s|^|JWT_PRIVATE_KEY=|g'); sed -i "s|^JWT_PRIVATE_KEY.*|$LINE|g" -i ./web-app/.env.docker
Fill JWT_PUBLIC_KEY in .env.docker:
LINE=$(cat ./web-app/jwtRS256.key.pub | tr 'n' '$' | sed 's|$|\\n|g;s|^|JWT_PUBLIC_KEY=|g'); sed -i "s|^JWT_PUBLIC_KEY.*|$LINE|g" -i ./web-app/.env.docker
- Fill some other variables
SERVER_HOST should be set to your HTTP host configured in Nginx or any other reverse-proxy server.
On official app this variable is set to cryptboard.io
SERVER_PORT should be a port, that is op
