ARSoft.WinFormsLicensing 1.4.2

ARSoft WinForms Licensing

A robust time-based licensing library for Windows Forms applications that provides secure license management with encryption, dual storage, and comprehensive validation.

🚀 Features

• Time-based Licensing: Create licenses with configurable expiration periods
• Dual Storage: Stores licenses in both local files and Windows Registry
• Encryption: AES encryption with PBKDF2 key derivation
• Tamper Protection: SHA256 checksums prevent license modification
• Flexible Distribution: Direct data registration or encrypted .lic file import
• Logging: Built-in with Microsoft.Extensions.Logging
• Dual Usage Patterns: ForCreation() and ForValidation()
• Extended Default License: 366-day default validity
• License Detection: Built-in presence and validation methods

📦 Installation

PM> Install-Package ARSoft.WinFormsLicensing

or

dotnet add package ARSoft.WinFormsLicensing

🔧 Core Concepts

1. Factory Methods

   • ForCreation() – Full-featured manager for vendor tools and registration (requires password & salt)
   • ForValidation() – Lightweight manager for client-side validation only

2. License Lifecycle

   • Creation: Generate and distribute licenses (default 366 days)
   • Registration: Import or enter license data in customer app
   • Validation: Multi-layer validation (checksum + expiration)
   • Storage: Saved to both %AppData% and Windows Registry

3. Security

   • AES + PBKDF2 (100k iterations, SHA256)
   • SHA256 checksums for tamper detection
   • Client hashing (no sensitive info stored)

🛠️ Basic Implementation

Initialization

// Vendor side (creation/registration)
var licenseManager = LicenseManager.ForCreation(
    logger, "StrongPassword123!", Encoding.UTF8.GetBytes("UniqueSalt123"),
    "MyApp", "license.json", "SOFTWARE\MyCompany\MyApp\License");

// Client side (validation only)
var licenseManager = LicenseManager.ForValidation(
    "MyApp", "license.json", "SOFTWARE\MyCompany\MyApp\License");

License Workflows

Workflow A: Direct Registration

1. Vendor creates license with CreateLicense()
2. Customer enters license data in registration window
3. Application registers via RenewLicense()

Workflow B: File Distribution

1. Vendor generates encrypted .lic file with LicenseGenerator.GenerateLicenseFile()
2. Customer imports using ImportLicenseFile()

Workflow C: Hybrid

• Initial registration by data
• Renewals via .lic files

License Validation

if (!licenseManager.IsLicensePresent()) { ShowRegistrationForm(); return; }

var (isValid, message, days) = licenseManager.ValidateLicense();
if (!isValid) { ShowError(message); Application.Exit(); }
if (days <= 30) { ShowWarning(message); }

📝 Configuration

Factory Methods

Key Methods

Storage

• File: %AppData%\[AppName]\[SettingsFile]
• Registry: HKEY_CURRENT_USER\[RegistryKeyPath]

🔒 Best Practices

• Use strong password + unique salt (≥8 bytes)
• Distribute licenses securely (encrypted channels)
• Validate on startup and periodically
• Handle validation errors gracefully
• Keep password/salt consistent across vendor & client

📋 Requirements

• .NET 6.0+
• Windows OS (registry required)
• Microsoft.Extensions.Logging
• Newtonsoft.Json

📄 License

MIT License - see LICENSE

📞 Support

Open an issue on GitHub for bug reports or feature requests.

🔄 Version History

v1.4.2

• Minor fixes and performance improvements

v1.4.1

• Minor fixes and performance improvements

v1.4.0

• Added ImportLicenseFile()
• Added LicenseGenerator utility

v1.3.0

• Breaking: LicenseUtils made public
• Enhanced validation & error handling

v1.2.0

• Introduced factory methods (ForCreation/ForValidation)
• Added IsLicensePresent() and LoadValidLicense()

v1.0.0

• Initial release (time-based, dual storage, AES encryption)