VerySecureChat v2.0

End-to-end encrypted chat using GPG encryption system.

BLIND RELAY ARCHITECTURE: The server acts as a pure relay - it only passes encrypted messages between clients without any ability to decrypt them. The server never sees plaintext content, making it a "blind" intermediary. Since the code is open-source Python, it can be independently audited for security.

Architecture

+----------------------------------------------------------------------+
|                         VERY SECURE CHAT                             |
|                           ARCHITECTURE v2.0                          |
+----------------------------------------------------------------------+

   +-----------+                              +-----------+
   |  CLIENT A |                              |  CLIENT B |
   |  (User)   |                              |  (User)   |
   +------+----+                              +------+----+
          |                                        |
          |    [GPG Encrypt]                       |    [GPG Encrypt]
          |    UID: user_A                         |    UID: user_B
          v                                        v
   +-----------------------------------------------------------+
   |                     SERVER (Relay)                        |
   |                     ----------------                      |
   |  Port: 13031                                           |
   |  Mode: Blind Relay (relays encrypted messages only)    |
   |  Max Message: 5MB (OOM protection)                     |
   |  Heartbeat: 30s                                       |
   +-----------------------------------------------------------+
          |                                        |
          |    [GPG Decrypt]                       |    [GPG Decrypt]
          v                                        v
   +-----------+                              +-----------+
   | Decrypted |                              | Decrypted |
   |  Message  |                              |  Message  |
   +-----------+                              +-----------+


+----------------------------------------------------------------------+
|                      MESSAGE FLOW                                   |
+----------------------------------------------------------------------+

  Client A                    Server                      Client B
     |                          |                          |
     |--[GPG Encrypt(msg)]----->|                          |
     |                          |--[Blind Relay]---------->|
     |                          |                          |--[GPG Decrypt]
     |                          |                          |
     |<--[Blind Relay]----------|<--[GPG Encrypt(msg)]-----|


+----------------------------------------------------------------------+
|                         COMPONENTS                                   |
+----------------------------------------------------------------------+

  CLIENT (client.v.2.0.py)
  +-- GUI: Tkinter
  +-- Encryption: GPG (python-gnupg)
  +-- Port: 13031 (configurable)
  +-- Functions:
      +-- Select recipient (individual or broadcast)
      +-- Encrypt messages with GPG
      +-- Decrypt received messages
      +-- Live key reload

  SERVER (server.v.2.0.py)
  +-- Mode: TCP Socket (blind relay)
  +-- Port: 13031 (default)
  +-- Security: 5MB message limit
  +-- Heartbeat: Ping/Pong every 30s
  +-- GUI: Optional (configurable)


+----------------------------------------------------------------------+
|                      REQUIREMENTS                                     |
+----------------------------------------------------------------------+

  Python 3.11+
  python-gnupg
  GPG installed on system

  Linux/macOS: brew install gnupg
  Windows: https://gpg4win.org/

Screenshots

Server

Client

Installation

pip install python-gnupg

Configuration

Server (server_config.json)

{
    "address": "0.0.0.0",
    "port": 13031,
    "gui": false,
    "debug": false
}

• address: Server IP address (use 0.0.0.0 for all interfaces)
• port: TCP port (default: 13031, can be changed)
• gui: Enable GUI (true/false)
• debug: Enable debug logging (true/false)

Client (client_config.json)

{
    "server": "127.0.0.1",
    "port": 13031,
    "debug": false,
    "GPGid": "YOUR_KEY_ID"
}

• server: Server hostname/IP address (can be changed to your server's IP)
• port: Server port (default: 13031, must match server config)
• debug: Enable debug logging (true/false)
• GPGid: Your GPG key ID (REQUIRED - must match your private key)

Usage

The project includes two shell scripts to run server and client:

# Start server (uses venv)
./run_server_v2.0.sh

# Start client (uses venv)
./run_client_v2.0.sh

Or run directly:

# Start server
python server.v.2.0.py

# Start client
python client.v.2.0.py

Prerequisites

You must have GPG keys configured:

gpg --full-generate-key
gpg --list-secret-keys
gpg --list-public-keys

Security Features

• End-to-End Encryption: Only the recipient can read messages
• Blind Relay: Server only sees encrypted messages, never plaintext - it cannot decrypt anything
• Auditable Code: 100% Python open-source - anyone can review the server logic
• OOM Protection: 5MB message limit
• Heartbeat: Connection monitoring

Limitations

• No user authentication (server doesn't verify key ownership)
• No rate limiting (vulnerable to flood attacks)
• Public keys must be shared manually between users

Version

v2.5 - Latest

Credits

Thanks to IGNIZ for many changes and improvements.