livia-test/Livia/Models/SerialKeyManager.cs

using System.Management;
using System.Text.Json;
using Livia.Properties;
using Microsoft.Extensions.Logging;

namespace Livia.Models;

public interface ISerialKeyManager
{
    bool Validate();
    string HardwareId { get; }
    string EncryptLicense(AuthenticationKeyLicense license);
}

public  readonly record struct AuthenticationKeyLicense
{
    public string HardwareId { get; init; }
    public DateTime ExpireDateTime { get; init; }
}

internal class SerialKeyManager : ISerialKeyManager
{
    private readonly ILogger _logger;
    private readonly IAesOperation _aesOperation;
    public string HardwareId { get; } = string.Empty;

    private const string AesKey = "L2CzateeJgdwxVA6ipQ8aj4sxvTWTzd4";

    public SerialKeyManager(ILogger logger, IAesOperation aesOperation)
    {
        _logger = logger;
        _aesOperation = aesOperation;

        using ManagementObjectSearcher searcher = new("select UUID from Win32_ComputerSystemProduct");

        ManagementObjectCollection information = searcher.Get();
        foreach (ManagementBaseObject? obj in information)
        {
            foreach (PropertyData data in obj.Properties)
            {
                _logger.LogInformation("{name} = {value}", data.Name, data.Value);
                HardwareId = (string)data.Value;
            }
        }
    }

    public bool Validate()
    {
        string authenticationKey = Settings.Default.AuthenticationKey;
        _logger.LogInformation("AuthenticationKey = {value}", Settings.Default.AuthenticationKey);
        string jsonString = _aesOperation.DecryptString(AesKey, authenticationKey);

        try
        {
            AuthenticationKeyLicense license = JsonSerializer.Deserialize<AuthenticationKeyLicense>(jsonString);
            if (!string.Equals(HardwareId, license.HardwareId))
                throw new Exception("Hardware ID mismatch");

            if (license.ExpireDateTime < DateTime.Now)
                throw new Exception("Auth key expired");

            return true;
        }
        catch (Exception e)
        {
            _logger.LogError(e, "Cannot decrypt auth key");
        }

        //reset to empty if incorrect
        Settings.Default.AuthenticationKey = string.Empty;
        return false;
    }

    public string EncryptLicense(AuthenticationKeyLicense license)
    {
        return _aesOperation.EncryptString(AesKey, JsonSerializer.Serialize(license));
    }
}