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.

Important

Account Required: This library requires a publisher account at license-management.com.

Free with Dev Subscription: A developer subscription is available at no cost, which provides full access to all features for development and testing purposes.

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 LicenseManagement.EndUser

Or via NuGet Package Manager:

Install-Package LicenseManagement.EndUser

Warning

Breaking Change in v2.0.0: The package has been renamed from Hymma.Lm.EndUser to LicenseManagement.EndUser. See the Migration Guide below.

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

State	Description
Valid	Active paid subscription
ValidTrial	Within trial period
InValidTrial	Trial period expired
Expired	License has expired
ReceiptExpired	Subscription ended
ReceiptUnregistered	Computer unregistered from receipt

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.

Migrating from v1.x

Version 2.0.0 introduces a breaking change: the namespace has been renamed from Hymma.Lm.EndUser to LicenseManagement.EndUser.

Steps to Migrate

1. Update NuGet Package Reference

   # Remove old package
   dotnet remove package Hymma.Lm.EndUser
   
   # Add new package
   dotnet add package LicenseManagement.EndUser

2. Update Namespace Imports Replace all occurrences:

   // Old
   using Hymma.Lm.EndUser;
   
   // New
   using LicenseManagement.EndUser;

3. Update Assembly References (if using direct DLL reference)

   • Old: Hymma.Lm.EndUser.dll
   • New: LicenseManagement.EndUser.dll

What Changed

v1.x	v2.0.0
Hymma.Lm.EndUser namespace	LicenseManagement.EndUser namespace
Hymma.Lm.EndUser.dll	LicenseManagement.EndUser.dll
NuGet: Hymma.Lm.EndUser	NuGet: LicenseManagement.EndUser

All classes, methods, and APIs remain unchanged - only the namespace has been updated for consistency.

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