ChashApp

Modern desktop encryption app built with C# and Avalonia UI.

ChashApp lets you encrypt files, folders, and notes with a clean dark interface, multilingual UI, operation history, export tools, CLI support, and a Windows installer. The project was built as a portfolio-ready desktop product with real publish, packaging, and release flow.

Overview

ChashApp focuses on practical local encryption:

• encrypt and decrypt files with a user password
• encrypt a whole folder into a single .chash container
• encrypt and decrypt notes directly inside the app
• verify encrypted containers
• export operation history to JSON or CSV
• publish and package the app like a real desktop product

The app targets Windows, Linux, and macOS.
The current UI supports English, Polish, Spanish, and German.

Features

• AES-256-GCM encryption
• PBKDF2-SHA256, PBKDF2-SHA512, and Argon2id
• file, folder, and note encryption
• drag and drop support
• secure erase flow
• operation history with search and pagination
• recent files and quick actions
• CLI commands: encrypt, decrypt, verify
• portable mode support
• Windows installer with uninstall flow
• multilingual interface
• tests, smoke tests, benchmarks, publish scripts, and release workflow

Screenshots

Main UI

Note Encryption

History

Settings

Branding reference:

• docs/brand-guide.md

Tech Stack

• C#
• .NET 9
• Avalonia UI
• AES-256-GCM
• PBKDF2 / Argon2id
• xUnit
• Inno Setup

Project Structure

ChashApp/
├─ .github/                    # CI / release workflow
├─ benchmarks/                 # benchmark project
├─ docs/                       # preview, branding, release notes
├─ installer/                  # Inno Setup script and assets
├─ publish/                    # publish scripts
├─ src/
│  └─ ChashApp/                # main desktop application
├─ tests/
│  └─ ChashApp.Tests/          # unit and UI smoke tests
├─ .gitignore
├─ ChashApp.sln
├─ global.json
└─ README.md

Run Locally

Visual Studio / Rider

1. Install .NET 9 SDK
2. Open ChashApp.sln
3. Restore packages
4. Run the ChashApp project

CLI

dotnet run --project src/ChashApp/ChashApp.csproj -- encrypt sample.txt "ExamplePassword123!" argon2id
dotnet run --project src/ChashApp/ChashApp.csproj -- decrypt sample.txt.chash "ExamplePassword123!"
dotnet run --project src/ChashApp/ChashApp.csproj -- verify sample.txt.chash "ExamplePassword123!"

Windows Build Flow

dotnet test .\tests\ChashApp.Tests\ChashApp.Tests.csproj
.\publish\publish-win-x64.ps1
.\installer\build-installer.ps1

Published app:

• artifacts\publish\win-x64\ChashApp.exe

Installer:

• artifacts\installer\ChashApp-Setup.exe

Publish Scripts

Windows

.\publish\publish-win-x64.ps1

Linux

.\publish\publish-linux-x64.ps1

macOS

.\publish\publish-osx-arm64.ps1

Installer

After publishing the Windows build:

.\installer\build-installer.ps1

The installer supports:

• desktop install flow
• uninstall flow
• Start Menu shortcuts
• .chash file association for the current user

Testing

dotnet test .\tests\ChashApp.Tests\ChashApp.Tests.csproj

Benchmarks:

dotnet run -c Release --project .\benchmarks\ChashApp.Benchmarks\ChashApp.Benchmarks.csproj

Security Notes

• encryption is based on AES-256-GCM
• key material is derived from the user password
• supported KDF options are PBKDF2-SHA256, PBKDF2-SHA512, and Argon2id
• files and notes are processed locally
• history does not store passwords
• lost passwords cannot be recovered
• secure erase reduces simple recovery risk, but should not be treated as an absolute guarantee on every drive or filesystem