Hymma.Lm.EndUser 1.3.0

LicenseManagement.EndUser

End-user SDK for license-management.com - A license management platform for software vendors.

This library is designed for client-side applications (desktop apps, plugins, add-ins) to validate licenses, handle trials, and manage activations.

Features

• License Validation - Validate licenses at application launch
• Trial Management - Automatic trial period handling with anti-tampering
• Installation Handling - Register computers during application install
• Uninstall Support - Properly unregister computers to free seats
• Offline Support - License validation works offline after initial activation
• Digital Signatures - RSA signature verification for license files
• Time Sync Detection - Detects system clock tampering
• Hardware Identification - Secure device fingerprinting

Installation

dotnet add package Hymma.Lm.EndUser

Or via NuGet Package Manager:

Install-Package Hymma.Lm.EndUser

Quick Start

1. Configure Publisher Preferences

using LicenseManagement.EndUser;

var preferences = new PublisherPreferences
{
    VendorId = "VDR_01ABC...",      // Your vendor ID
    ProductId = "PRD_01XYZ...",     // Your product ID
    ApiKey = "your-client-api-key", // Client API key (NOT master key)
    PublicKey = "<RSAKeyValue>...</RSAKeyValue>", // For signature verification
    TrialDays = 14,                 // Trial period duration
    ValidDays = 90                  // License cache validity
};

2. Handle License at Installation

// During MSI/Setup installation
var context = new LicHandlingContext(preferences);

var installHandler = new LicenseHandlingInstall(
    context,
    onSuccess: (ctx) => {
        Console.WriteLine("License installed successfully!");
    }
);

await installHandler.HandleLicenseAsync();

3. Validate License at Launch

// At application startup
var context = new LicHandlingContext(preferences);

var launchHandler = new LicenseHandlingLaunch(
    context,
    onLicenseHandledSuccessfully: (license) => {
        Console.WriteLine($"License valid until: {license.Expires}");
    },
    onCustomerMustEnterProductKey: () => {
        // Show product key entry dialog
        return GetProductKeyFromUser();
    },
    onTrialValidated: () => {
        Console.WriteLine("Trial period active");
        return null;
    },
    onTrialEnded: (prefs) => {
        // Show trial expired message
        MessageBox.Show("Your trial has expired. Please purchase a license.");
    },
    onLicFileNotFound: (ctx) => {
        // License file missing - may need reinstall
    }
);

await launchHandler.HandleLicenseAsync();

4. Handle Uninstallation

// During uninstall to free up the license seat
var context = new LicHandlingContext(preferences);

var uninstallHandler = new LicenseHandlingUninstall(
    context,
    onSuccess: (ctx) => {
        Console.WriteLine("Computer unregistered successfully");
    }
);

await uninstallHandler.HandleLicenseAsync();

License States

Events

The LicHandlingContext provides events for handling license state changes:

context.OnCustomerMustEnterProductKey += () => { /* Show key entry UI */ };
context.OnTrialValidated += () => { /* Trial is active */ };
context.OnLicenseFileNotFound += () => { /* Handle missing license */ };
context.OnTrialEnded += () => { /* Trial expired */ };
context.OnLicenseHandledSuccessfully += () => { /* Success */ };

Custom Metadata

Attach custom metadata to licenses during installation:

preferences.BeforeLicensePost += (sender, args) => {
    args.Metadata["CustomerName"] = "John Doe";
    args.Metadata["OrderId"] = "ORD-12345";
};

Storage Locations

• Computer ID: Windows Registry (HKLM\Software\Hymma\LicenseManagement)
• License File: %LocalAppData%\License-Management.com\{VendorId}\{ProductName}.lic

Exception Handling

try
{
    await launchHandler.HandleLicenseAsync();
}
catch (ComputerOfflineException)
{
    // No internet - but offline validation may still work
}
catch (CouldNotReadLicenseFromDiskException)
{
    // License file corrupted or missing
}
catch (LicenseExpiredException)
{
    // License has expired
}
catch (ReceiptExpiredException)
{
    // Subscription ended
}
catch (ApiException ex)
{
    // API communication error
    Console.WriteLine($"API Error: {ex.StatusCode}");
}

Requirements

• .NET Framework 4.8.1
• Windows OS (uses WMI for hardware identification)
• Internet connection for initial activation (offline afterward)

Security Features

• RSA Signature Verification - Licenses are digitally signed
• Hardware Fingerprinting - CPU + Motherboard serial numbers
• Time Tampering Detection - NTP sync validation
• Secure Registry Storage - Computer ID in HKLM

Sample Applications

We provide sample applications demonstrating real-world usage patterns:

WiX Installer Custom Action

The WiX Custom Action Sample demonstrates how to integrate license management into a WiX installer:

• Register computers during installation
• Unregister computers during uninstallation
• Pass configuration via CustomActionData

// Example custom action
[CustomAction]
public static ActionResult InstallLicense(Session session)
{
    var preferences = GetPreferences(session, "ProductId");
    var context = new LicHandlingContext(preferences);
    var handler = new LicenseHandlingInstall(context, null);
    handler.HandleLicense();
    return ActionResult.Success;
}

See the sample README for complete setup instructions.

Changelog

See CHANGELOG.md for version history and release notes.

License

MIT - See LICENSE for details.

Related Packages

• LicenseManagement.Client - Server-side SDK for vendors
• LicenseManagement.EndUser.Wpf - WPF UI components

Documentation

• API Documentation
• LLMs.txt for AI Tools