Cripta Messenger

Peer to peer encrypted & signed messaging via MQTT pub/sub.

With Cripta you can relay secure messages instantly using free (and mostly available) MQTT brokers. The broker is configurable, to use a different broker edit, rebuild the app and distribute that.

Tests

There are no tests in this project. It started as an afternoon hack. I hope to add at some point.

Features

• Asymmetric encryption using recipient public key
• Inbox management (list, read, delete & empty)
• Mail groups
• Message signing with private key

Releases

Download an executable for your OS here.

Usage

Create a config.env file in same directory as the cripta executable. Add your Twitter username.

## Enter your twitter username without the @ symbol
TWITTER_USERNAME=olliephillips

Note: There is currently no validation of the username against Twitter. You could pick any username.

Run it on Mac/Linux.

./cripta

Cripta Messenger
---------------------
Version: v0.0.1
Go version: 1.19
---------------------

Enter 'help' for command list.

Show command list with help.

> help
Showing available commands..

Command List
------------
help                    Show available commands
list                    List all messages in mailbox
friends                 List available friends (with public keys)
groups                  List available groups
read <msgId>            Print the message with id <msgId> to the console
delete <msgId>          Delete the messsage with id <msgId> from mailbox
empty                   Delete all messages in the mailbox
quit                    Quit the program

To send a message to a single recipient:-
> @<username> <subject>::<message>

To send to a group of recipients (group must exist):-
> -><groupname> <subject>::<message>

The message(s) will be queue and published.

Receiving messages

To receive a message from someone else you must have shared your public key in my_public_key.txt with the sender.

Sending messages

You can send messages to any user who's public key you have saved in your friends folder. By default the folder is friend_keys. A user's key is saved in a .txt file named with their username e.g. username.txt.

You can send test messages to yourself. On first start your public key is created and copied to the friend_keys folder.

Use this format to send to a user.

> @<username> <subject>::<message>

Creating groups

You can also send to groups. To create a group, create a named .txt file in the groups folder (default), e.g. mygroup.txt. Add usernames (for whom you hold a public key) one per line, including the @ symbol.

@user1
@user2

Use this format to send to a group:

> -><groupname> <subject>::<message>

License

MIT