Sigma Encrypted Messaging App

Sigma is a secure and encrypted messaging application built using .NET MAUI. This app provides end-to-end encryption for private conversations, ensuring the security and privacy of your messages.

Features

• End-to-End Encryption: Messages are encrypted using AES and RSA algorithms to ensure privacy and security.
• User Authentication: Secure user authentication and key management.
• Real-Time Messaging: Instant messaging with real-time updates using SignalR.
• Cross-Platform Support: Available on Android, iOS, macOS, and Windows.

Screenshots

Getting Started

Prerequisites

• .NET 6.0 SDK or later
• Visual Studio 2022 or later with .NET MAUI workload installed
• SQLite database

Installation

1. Clone the repository

   git clone https://github.com/your_username/sigma-encrypted-messaging-app.git
   cd sigma-encrypted-messaging-app

2. Restore NuGet packages

   dotnet restore

3. Update the configuration

   Update the configuration settings in appsettings.json or relevant configuration files.

4. Run the application

   Open the solution in Visual Studio and run the project on your preferred platform.

Usage

1. Register a New User

   • Open the app and register with a unique username.
   • The app generates RSA key pairs and stores them securely.

2. Add Contacts

   • Navigate to the "Add Contact" page.
   • Enter the username of the contact you want to add.

3. Start a Conversation

   • Select a contact from your contacts list.
   • Start a new conversation and send encrypted messages.

Project Structure

• Models: Contains data models such as User, Message, and Conversation.
• ViewModels: Contains view models to manage the UI logic.
• Views: Contains XAML pages and their code-behind files.
• Services: Contains services for encryption, decryption, and API interactions.
• Converters: Contains value converters for data binding in XAML.

Encryption Details

AES Encryption

• Key Size: 256-bit
• Mode: CBC (Cipher Block Chaining)
• Padding: PKCS7

RSA Encryption

• Key Size: 2048-bit or higher
• Usage: Encrypting AES keys for secure transmission

HMAC

• Algorithm: HMAC-SHA256
• Usage: Ensuring message integrity and authenticity

Contributing

Contributions are welcome! Please fork the repository and submit pull requests for any enhancements, bug fixes, or new features.

1. Fork the Project
2. Create your Feature Branch (git checkout -b feature/AmazingFeature)
3. Commit your Changes (git commit -m 'Add some AmazingFeature')
4. Push to the Branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

License

Distributed under the MIT License. See LICENSE for more information.

Contact

Tom Muir

• GitHub: tmuird

Acknowledgements

• Prism
• SignalR
• Refit
• crypto

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