EncSend

EncSend is a tool for sending encrypted messages between hosts.

EncSend was created just for fun. Don't use it in the production with any kinds of sensitive data. I am not a Cryptography Enthusiast or a Security Engineer, I can't grant reliability of this tool and safety of your data. Note, every crypto tool has to be audited by experts before using, and this one wasn't.

EncSend is free and opensource software, it is licensed under GNU GPL 3 (or newer) license. Check LICENSE for details.

Usage

• Copy encsend/conf_default.py to encsend/conf.py, edit conf.py. Otherwise you should use --dsn, --path, --host, --port arguments in next steps.
• Run init

encsend-cmd.py init

• See help for additional details encsend-cmd.py --help

Receiving messages

• Add a host, this host will be able to send messages to you

encsend-cmd.py host-add -k somehost_hex_encoded_verify_key --host localhost --port 8888 

• Start a server

encsend-cmd.py server

Sending messages

• Receiver has to add your host
• Send a message

encsend-cmd.py message-send -k receiver_hex_encoded_verify_key -m message

• or you can use internal host's id

encsend-cmd.py host-ls
encsend-cmd.py message-send --id receiver_internal_id -m message

How it works

• Every host has singing key and verify key, private key and public key
• Messages are signed with author's signing key, after that messages are encrypted with SealedBox from pynacl/libsodium, that's why only receiver are able to decrypt a message and auth an author

EncSend uses

• Python 3.6+ and asyncio
• PyNaCl and libsodium
• aioodbc and pyodbc

Sending messages

• Get a text message, encode it to bytes, the result is message
• Get receiver's verify key, host and port from db
• Sign message with your signing key, the result is signed
• Place signed and your hex encoded verify key to json {"host": "some_hex_encoded_data", "message": "some_signed_message"}, the resuls is json_data
• Get curve25519 public key from receiver's verify key
• Create SealedBox with public key, encrypt json_data and use HexEncoder
• Send the result to receiver

Receiving messages

• Recieve some data
• TODO: check magic byte
• Get curve25519 private key from your signing key
• Create SealedBox with private key
• Decrypt data, use HexEncoder, the result is json_data
• Check does sender exist in your db
• Check signature of json_data['message']
• Decode json_data['message'] and save the result