configureappio

    public class HomeController : Controller
    {
        private readonly IMyAppSettings _settings;

        public HomeController(IMyAppSettings settings)
        {
            _settings = settings ?? throw new ArgumentNullException(nameof(settings));
        }
        public IActionResult Index()
        {

configureappio

        public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvc();
            services.AddOptions();            
            services.Configure<MyAppSettings>(Configuration.GetSection("MyAppSettings"));
            services.AddSingleton(Configuration);        

            // In a real implementation, you would have a factory here to get the password and salt securely
            // from somewhere such as Azure Key Vault, Environmental variable / another json setting (obfuscated in some way)
            services.AddSingleton( x => new CryptoFactory().Create<AesManaged>("Password", "Salt"));

configureappio

    public class Program
    {
        public static void Main(string[] args)
        {
            BuildWebHost(args).Run();
        }

        public static IWebHost BuildWebHost(string[] args)
        {
            var webhost = WebHost.CreateDefaultBuilder(args);

configureappio

{
  "Logging": {
    "IncludeScopes": false,
    "LogLevel": {
      "Default": "Warning"
    }
  },
  "MyAppSettings": {
    "ApplicationName": "My Cool Application",
    "Secrets": {

configureappio

    public class MyAppSettings : IAppSettingsStructure
    {
        public string ApplicationName { get; set; }
        public Dictionary<string, string> Secrets { get; set; } = new Dictionary<string, string>();
    } 

configureappio

    public interface ICryptoFactory
    {
        ICryptoAlgorithm Create<T>(string password, string salt) where T : SymmetricAlgorithm, new();
        ICryptoAlgorithm Create(Type type, string password, string salt);
    }

    public interface ICryptoAlgorithm
    {
        string Decrypt(string text);
        string Encrypt(string text);

configureappio

    public class SettingsDecryptor : ISettingsDecrypt
    {
        private readonly ICryptoAlgorithm _crypto;
        public SettingsDecryptor(ICryptoAlgorithm crypto)
        {
            _crypto = crypto ?? throw new ArgumentNullException(nameof(crypto));
        }

        public string Decrypt(string key, IDictionary<string, string> keyValues)
        {

configureappio

    public class SettingsValidator : ISettingsValidator
    {
        public bool TryValidate(IAppSettingsStructure settings, out AggregateException validationExceptions)
        {
            if (settings == null) throw new ArgumentNullException(nameof(settings));
            
            var exceptions = new List<Exception>();

            if (settings.ApplicationName == null) exceptions.Add(new ArgumentNullException(nameof(settings.ApplicationName)));
            if (string.IsNullOrWhiteSpace(settings.ApplicationName)) exceptions.Add(new ArgumentOutOfRangeException(nameof(settings.ApplicationName)));

configureappio

    public class MyAppSettingsBridge : IAppSettingsResolved
    {
        private readonly IOptions<MyAppSettings> _appSettings;

        private readonly ISettingsDecrypt _decryptor;

        public MyAppSettingsBridge(IOptionsSnapshot<MyAppSettings> appSettings, ISettingsDecrypt decryptor, ISettingsValidator validator) {
            _appSettings = appSettings ?? throw new ArgumentNullException(nameof(appSettings));
            _decryptor = decryptor ?? throw new ArgumentException(nameof(decryptor));
            if (validator == null) throw new ArgumentNullException(nameof(validator));

configureappio

public interface IAppSettings
{
    string ApplicationName { get;  }        
}

public interface ISqlConnectionSettings 
{        
    string SqlConnectionSting { get; }
}