Enigma.LicenseManager 1.1.0

Enigma.LicenseManager

Enigma.LicenseManager is a comprehensive .NET library designed for secure license management in applications. It provides robust cryptographic protection using both traditional RSA and modern ML-DSA (FIPS 204) digital signature algorithms, ensuring your software licensing is both secure and future-proof.

Features

• Dual Cryptographic Support: Choose between RSA and ML-DSA (post-quantum) signatures
• Flexible License Management: Create, validate, and manage licenses with customizable properties
• Device Binding: Lock licenses to specific machines using hardware-derived device identifiers
• Cross-Platform Compatibility: Supports .NET Standard 2.0 and .NET 8.0+
• JSON Serialization: Easy license storage and distribution in JSON format
• Product Version Matching: Support for wildcard patterns in product IDs (e.g., MyApp 1.*)
• Expiration Handling: Built-in support for time-based license expiration
• Thread-Safe Service: LicenseService is fully thread-safe for concurrent access

Installation

dotnet add package Enigma.LicenseManager

License Creation

Create an RSA-Signed License

Generate a license with RSA digital signature for traditional cryptographic security:

await using var privateKeyFile = new FileStream("<YourKeyFile.pem>", FileMode.Open, FileAccess.Read);
var privateKey = PemUtils.LoadPrivateKey(privateKeyFile, "<KeyPassword>");

var license = new LicenseBuilder()
    .SetProductId("MyApp 1.*")
    .SetExpirationDate(DateTime.UtcNow.AddDays(365))
    .SetOwner("Acme Corp")
    .SignWithRsa(privateKey)
    .Build();

Create an ML-DSA-Signed License

Generate a license with ML-DSA (post-quantum) signature for enhanced future security:

await using var privateKeyFile = new FileStream("<YourKeyFile.pem>", FileMode.Open, FileAccess.Read);
var privateKey = PemUtils.LoadPrivateKey(privateKeyFile, "<KeyPassword>");

var license = new LicenseBuilder()
    .SetProductId("MyApp")
    .SignWithMlDsa(privateKey)
    .Build();

Create a Device-Bound License

Bind a license to a specific machine so it cannot be used elsewhere:

// On the target machine, generate the device ID
var deviceId = LicenseUtils.GenerateDeviceId();

// When creating the license, bind it to that device
var license = new LicenseBuilder()
    .SetProductId("MyApp 1.*")
    .SetDeviceId(deviceId)
    .SetExpirationDate(DateTime.UtcNow.AddDays(365))
    .SignWithRsa(privateKey)
    .Build();

Id defaults to a ULID and CreationDate defaults to DateTime.UtcNow when not explicitly set.

License Persistence

Save License to JSON

Export your generated license to a JSON file for distribution:

await using var fs = new FileStream("<DestinationPath>", FileMode.Create, FileAccess.Write);
await license.SaveAsync(fs);

Load License from JSON

Import a license from a JSON file for validation:

await using var fs = new FileStream("<LicenseFilePath>", FileMode.Open, FileAccess.Read);
var license = await License.LoadAsync(fs);

Both SaveAsync and LoadAsync accept an optional CancellationToken parameter.

License Validation

Verify a Single License

Validate a license against its public key. IsValid returns a (bool, string?) tuple with an error message on failure:

await using var publicKeyFile = new FileStream("<YourKeyFile.pem>", FileMode.Open, FileAccess.Read);
var publicKey = PemUtils.LoadKey(publicKeyFile);

var service = new LicenseService();
var (isValid, errorMessage) = service.IsValid(license, publicKey, "MyApp 1.0");

if (!isValid)
    Console.WriteLine($"License rejected: {errorMessage}");

For device-bound licenses, pass the device ID:

var deviceId = LicenseUtils.GenerateDeviceId();
var (isValid, errorMessage) = service.IsValid(license, publicKey, "MyApp 1.0", deviceId);

Using LicenseService

LicenseService maintains an in-memory, thread-safe collection of licenses. Register licenses once, then check validity by product ID throughout your application:

var service = new LicenseService();

// Register licenses with their public keys
service.AddLicense(license, publicKey);

// Check if any registered license is valid for a product
if (service.HasValidLicense("MyApp 1.0"))
{
    // Feature is licensed
}

// For device-bound licenses
var deviceId = LicenseUtils.GenerateDeviceId();
if (service.HasValidLicense("MyApp 1.0", deviceId))
{
    // Feature is licensed for this device
}

// Remove a license when no longer needed
service.RemoveLicense(license);

Project Structure