PanoramicData.LicenceMagic

Introduction

PanoramicData.LicenceMagic is a .NET 10 library for creating, signing, writing, reading, and validating application licence files.

Licence signatures are bound to a filename and validated against the licensed company, product, validity dates, and assembly version range.

Installation

dotnet add package PanoramicData.LicenceMagic

Usage

Define licence details with a fixed 16-byte initialization vector:

using PanoramicData.LicenceMagic;

public sealed class ProductLicence : LicenceDetails
{
	private static readonly byte[] InitVector =
		[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15];

	public ProductLicence() : base(InitVector)
	{
	}
}

Create and write a signed licence:

var salt = new byte[] { 0, 1, 2, 3, 4, 5, 6, 7 };
var file = new FileInfo("product.lic");
var details = new ProductLicence
{
	LicensedCompany = "Example Ltd",
	LicensedProduct = "Example Product",
	StartDateUtc = DateTime.UtcNow.Date,
	EndDateUtc = DateTime.UtcNow.Date.AddYears(1),
	StartVersion = "1.0",
	EndVersion = "2.0"
};

details.Sign(file.Name, salt);
new License<ProductLicence>(details).WriteToFile(file, salt);

Read and validate it:

var licence = new License<ProductLicence>(file);
var validation = licence.Validate(salt);
if (!validation.IsValid)
{
	throw new InvalidOperationException(validation.ErrorMessage);
}

Keep the salt and initialization vector stable and protect them as application secrets. Existing licence files depend on the values used when they were signed.

Contributing

See CONTRIBUTING.md.

License

This project is licensed under the MIT License. See LICENSE.