ARSoft.WinFormsLicensing 1.5.4

ARSoft WinForms Licensing

ARSoft WinForms Licensing is a Windows-focused licensing library for .NET applications. It creates, imports, renews, stores, and validates time-based licenses using encrypted local storage plus Windows Registry redundancy.

Features

• Time-based licenses with configurable validity
• AES encryption with PBKDF2 key derivation
• SHA256 checksum validation for tamper detection
• Dual storage in %AppData% and HKEY_CURRENT_USER
• Automatic repair when either file or registry copy is missing or invalid
• Encrypted .lic file generation and import
• Silent validation mode for client applications
• Optional logging for vendor tools and diagnostics

Installation

Install-Package ARSoft.WinFormsLicensing

dotnet add package ARSoft.WinFormsLicensing

Requirements

• .NET 8
• Windows
• Microsoft.Extensions.Logging
• Newtonsoft.Json

Setup

Use the same password and salt everywhere: vendor tools, license file generation, and customer applications. If they differ, existing licenses cannot be decrypted.

using System.Text;

var password = "YourSecurePassword123!";
var salt = Encoding.UTF8.GetBytes("YourUniqueSalt12345");
var appName = "MyApplication";
var settingsFile = "license.json";
var registryKeyPath = "SOFTWARE\\MyCompany\\MyApplication\\License";

Create And Store A License

Use ForCreation in vendor tools or admin flows. The logger is optional.

using ARSoft.WinFormsLicensing;

var manager = LicenseManager.ForCreation(
    logger: null,
    keyPassword: password,
    keySalt: salt,
    appName: appName,
    settingsFile: settingsFile,
    registryKeyPath: registryKeyPath);

var created = manager.CreateLicense(
    clientName: "Customer ABC",
    licensedDate: DateTime.Today,
    validityDays: 366,
    version: "1.0");

Validate A License

Use ForValidation in customer applications. The logger is optional (pass null for silent mode).

using ARSoft.WinFormsLicensing;

var manager = LicenseManager.ForValidation(
    password: password,
    salt: salt,
    appName: appName,
    settingsFile: settingsFile,
    registryKeyPath: registryKeyPath,
    logger: logger); // optional, defaults to null

var result = manager.ValidateLicense();

if (!result.IsValid)
{
    MessageBox.Show(result.Message, "License Validation");
    Application.Exit();
}

ValidateLicense() checks both storage locations. If one valid copy exists, the missing or corrupted copy is rebuilt automatically.

Generate A License File

Use LicenseGenerator.GenerateLicenseFile() to create encrypted .lic files for distribution. The logger is optional.

using ARSoft.WinFormsLicensing.Service.Helpers;

var generated = LicenseGenerator.GenerateLicenseFile(
    clientName: "Customer ABC",
    password: password,
    salt: salt,
    outputFile: @"C:\licenses\customer-abc.lic",
    validityDays: 366,
    startDate: DateTime.Today,
    version: "1.0",
    logger: null);

Import A License File

var imported = manager.ImportLicenseFile(@"C:\licenses\customer-abc.lic");

Renew From License Data

using ARSoft.WinFormsLicensing.Models;

var license = new LicenseData
{
    Client = providedClientHash,
    Licensed = providedLicensedDate,
    Expires = providedExpirationDate,
    Version = "1.0",
    Checksum = providedChecksum
};

var renewed = manager.RenewLicense(license);

Storage

settingsFile can also be an absolute path. Relative file names are stored under %AppData%\[AppName].

Main API

Validation Messages

Security Notes

• Use a strong password.
• Use a unique salt per application.
• Keep password and salt consistent across all tools for the same product.
• Distribute .lic files through a trusted channel.
• Validate licenses at startup and before sensitive workflows.
• Registry paths must start with SOFTWARE\.

Version History

v1.5.3

• Added optional ILogger parameter to LicenseManager.ForValidation() for diagnostics in client applications
• Added optional ILogger parameter to LicenseGenerator.GenerateLicenseFile() for logging during file generation
• Logger is now available across all library entry points (ForCreation, ForValidation, LicenseGenerator)

v1.5.2

• Fixed ForValidation() file lookup so it uses the same %AppData%\[AppName]\[SettingsFile] path as ForCreation()
• Fixed nullable logger support in ForCreation()
• Added argument validation for app name, settings file, registry path, password, salt, and version
• Added fixed-time checksum comparison
• Added invariant client hashing
• Added output directory creation for license file generation
• Added xUnit coverage for creation, validation, import, and checksum rejection
• Updated package metadata and documentation

v1.5.1

• Removed parameterless ForValidation() method
• Required password and salt for validation
• Unified encryption parameters between creation and validation modes

v1.5.0

• Added optional logger behavior
• Added LoggerEnabled

v1.4.0

• Added ImportLicenseFile()
• Added LicenseGenerator

v1.3.0

• Made LicenseUtils public
• Improved validation and error handling

v1.2.0

• Added factory methods
• Added IsLicensePresent()
• Added LoadValidLicense()

v1.0.0

• Initial release