feat(infra): create initial encryption implementations

src/FiscalOS.Infra/FiscalOS.Infra.csproj

@@ -4,6 +4,7 @@
     <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" />
     <PackageReference Include="Microsoft.Extensions.Hosting" />
+    <PackageReference Include="TestableIO.System.IO.Abstractions.Wrappers" />
   </ItemGroup>
 
   <ItemGroup>

src/FiscalOS.Infra/Security/Encryptor.cs

@@ -0,0 +1,105 @@
+
+namespace FiscalOS.Infra.Security;
+
+public sealed class Encryptor : IEncryptor
+{
+  private readonly IKeyRing _keyRing;
+
+  private Encryptor(IKeyRing keyRing)
+  {
+    _keyRing = keyRing;
+  }
+
+  public static Encryptor From(IServiceProvider serviceProvider)
+  {
+    var keyRing = serviceProvider.GetRequiredService<IKeyRing>();
+    return new Encryptor(keyRing);
+  }
+
+  public static Encryptor From(IKeyRing keyRing)
+  {
+    return new Encryptor(keyRing);
+  }
+
+  private KeyRingEntry PrimaryKey => _keyRing.GetPrimaryKey();
+
+  private static async Task<string> DecryptCoreAsync(string key, string cipherText, CancellationToken ct)
+  {
+    var cipherTextBytes = Convert.FromBase64String(cipherText);
+
+    using var aes = Aes.Create();
+    aes.Key = Convert.FromBase64String(key);
+
+    var iv = new byte[16];
+    Array.Copy(cipherTextBytes, 0, iv, 0, 16);
+    aes.IV = iv;
+
+    var decryptor = aes.CreateDecryptor();
+
+    using var memoryStream = new MemoryStream(cipherTextBytes, 16, cipherTextBytes.Length - 16);
+    using var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read);
+    using var streamReader = new StreamReader(cryptoStream);
+
+    return await streamReader.ReadToEndAsync(ct).ConfigureAwait(false);
+  }
+
+  public async Task<string> DecryptAsync(string cipherText, CancellationToken ct)
+  {
+    return await DecryptCoreAsync(PrimaryKey.Key, cipherText, ct).ConfigureAwait(false);
+  }
+
+  public async Task<string> DecryptAsyncFor(User user, string plainText, CancellationToken ct)
+  {
+    var decryptedKey = await DecryptCoreAsync(PrimaryKey.Key, user.EncryptedDataKey, ct).ConfigureAwait(false);
+    return await DecryptCoreAsync(decryptedKey, plainText, ct).ConfigureAwait(false);
+  }
+
+  private static async Task<string> EncryptCoreAsync(string key, string plainText, CancellationToken ct)
+  {
+    using var aes = Aes.Create();
+    aes.Key = Convert.FromBase64String(key);
+
+    using var memoryStream = new MemoryStream();
+    aes.GenerateIV();
+    await memoryStream.WriteAsync(aes.IV, ct).ConfigureAwait(false);
+
+    var encryptor = aes.CreateEncryptor();
+
+    using var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write);
+    using var streamWriter = new StreamWriter(cryptoStream);
+
+    await streamWriter.WriteAsync(plainText.ToCharArray(), ct).ConfigureAwait(false);
+    await streamWriter.FlushAsync(ct).ConfigureAwait(false);
+    streamWriter.Close();
+
+    return Convert.ToBase64String(memoryStream.ToArray());
+  }
+
+  public async Task<string> EncryptAsync(string plainText, CancellationToken ct)
+  {
+    return await EncryptCoreAsync(PrimaryKey.Key, plainText, ct).ConfigureAwait(false);
+  }
+
+  public async Task<string> EncryptAsyncFor(User user, string plainText, CancellationToken ct)
+  {
+    var decryptedKey = await DecryptCoreAsync(PrimaryKey.Key, user.EncryptedDataKey, ct).ConfigureAwait(false);
+    return await EncryptCoreAsync(decryptedKey, plainText, ct).ConfigureAwait(false);
+  }
+
+  public string GenerateKey()
+  {
+    using var aes = Aes.Create();
+    aes.GenerateKey();
+
+    return Convert.ToBase64String(aes.Key);
+  }
+
+  public async Task<EncryptedDataKey> GenerateEncryptedKeyAsync(CancellationToken ct)
+  {
+    var key = GenerateKey();
+    var keyUsed = PrimaryKey;
+    var encryptedKey = await EncryptCoreAsync(keyUsed.Key, key, ct).ConfigureAwait(false);
+    return EncryptedDataKey.From(keyUsed.KeyId, encryptedKey);
+  }
+
+}

src/FiscalOS.Infra/Security/FileKeyRing.cs

@@ -0,0 +1,90 @@
+
+namespace FiscalOS.Infra.Security;
+
+public sealed class FileKeyRing : IKeyRing, IDisposable
+{
+  private const string KeyFileExtension = ".key";
+  private FileKeyRingOptions _options;
+  private readonly IFileSystem _fileSystem;
+  private readonly IDisposable? _optionsChangeHandler;
+  private readonly Dictionary<string, KeyRingEntry> _keys = [];
+  private string KeyRingPath => _fileSystem.Path.GetFullPath(_options.KeysDirectoryPath, AppContext.BaseDirectory);
+
+  private FileKeyRing(IOptionsMonitor<FileKeyRingOptions> options, IFileSystem fileSystem)
+  {
+    _fileSystem = fileSystem;
+    _options = options.CurrentValue;
+
+    LoadKeys();
+
+    _optionsChangeHandler = options.OnChange(options =>
+    {
+      _options = options;
+      LoadKeys();
+    });
+  }
+
+  public static FileKeyRing From(IServiceProvider serviceProvider)
+  {
+    var options = serviceProvider.GetRequiredService<IOptionsMonitor<FileKeyRingOptions>>();
+    var fileSystem = serviceProvider.GetRequiredService<IFileSystem>();
+
+    return new(options, fileSystem);
+  }
+
+  public static FileKeyRing From(IOptionsMonitor<FileKeyRingOptions> options, IFileSystem fileSystem)
+  {
+    return new(options, fileSystem);
+  }
+
+  public KeyRingEntry GetKey(string keyId)
+  {
+    if (_keys.TryGetValue(keyId, out var key))
+    {
+      return key;
+    }
+
+    throw new KeyNotFoundException($"Key with ID '{keyId}' not found in the key ring.");
+  }
+
+  public KeyRingEntry GetPrimaryKey()
+  {
+    return GetKey(_options.PrimaryKeyId);
+  }
+
+  private void LoadKeys()
+  {
+    _keys.Clear();
+
+    if (_fileSystem.Directory.Exists(KeyRingPath))
+    {
+      var keyFiles = _fileSystem.Directory.GetFiles(KeyRingPath, $"*{KeyFileExtension}");
+
+      foreach (var keyFile in keyFiles)
+      {
+        var keyId = _fileSystem.Path.GetFileNameWithoutExtension(keyFile);
+        var key = _fileSystem.File.ReadAllText(keyFile).Trim();
+
+        if (string.IsNullOrEmpty(key) is false)
+        {
+          _keys[keyId] = KeyRingEntry.From(keyId, key);
+        }
+      }
+    }
+  }
+
+  public void Dispose()
+  {
+    _optionsChangeHandler?.Dispose();
+  }
+
+  public async Task<KeyRingEntry> SaveKeyAsync(string key)
+  {
+    var id = Guid.NewGuid().ToString();
+    var entry = KeyRingEntry.From(id, key);
+    var filename = id + KeyFileExtension;
+    var entryPath = _fileSystem.Path.Combine(KeyRingPath, filename);
+    await _fileSystem.File.WriteAllTextAsync(entryPath, key).ConfigureAwait(false);
+    return entry;
+  }
+}

src/FiscalOS.Infra/Security/FileKeyRingOptions.cs

@@ -0,0 +1,23 @@
+namespace FiscalOS.Infra.Security;
+
+public sealed record FileKeyRingOptions
+{
+  public string KeysDirectoryPath { get; init; } = string.Empty;
+  public string PrimaryKeyId { get; init; } = string.Empty;
+}
+
+public sealed record class FileKeyRingOptionsSetup : IConfigureOptions<FileKeyRingOptions>
+{
+  private const string SectionName = nameof(FileKeyRingOptions);
+  private readonly IConfiguration _configuration;
+
+  public FileKeyRingOptionsSetup(IConfiguration configuration)
+  {
+    _configuration = configuration;
+  }
+
+  public void Configure(FileKeyRingOptions options)
+  {
+    _configuration.GetSection(SectionName).Bind(options);
+  }
+}

src/FiscalOS.Infra/Usings.cs

@@ -1,4 +1,5 @@
 global using System.IdentityModel.Tokens.Jwt;
+global using System.IO.Abstractions;
 global using System.Security.Claims;
 global using System.Security.Cryptography;
 global using System.Text;
@@ -7,10 +8,13 @@ global using System.Text.Json;
 global using FiscalOS.Core.Authentication;
 global using FiscalOS.Core.Data;
 global using FiscalOS.Core.Identity;
+global using FiscalOS.Core.Security;
 global using FiscalOS.Infra.Authentication;
 global using FiscalOS.Infra.Authorization;
 global using FiscalOS.Infra.Data;
+global using FiscalOS.Infra.Security;
 
+global using Microsoft.AspNetCore.Authentication.JwtBearer;
 global using Microsoft.AspNetCore.Authorization;
 global using Microsoft.AspNetCore.Authorization.Policy;
 global using Microsoft.AspNetCore.Http;