Init Commit

Backend/GestorFacturas.API/Services/EncryptionService.cs

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+using System.Security.Cryptography;
+using System.Text;
+using GestorFacturas.API.Services.Interfaces;
+
+namespace GestorFacturas.API.Services;
+
+public class EncryptionService : IEncryptionService
+{
+  private readonly string _key;
+
+  public EncryptionService(IConfiguration config)
+  {
+    // La clave debe venir del .env / appsettings
+    _key = config["EncryptionKey"] ?? throw new ArgumentNullException("EncryptionKey no configurada");
+
+    // Ajustar si la clave no tiene el tamaño correcto (AES-256 requiere 32 bytes)
+    // Aquí hacemos un hash SHA256 de la clave para asegurar que siempre tenga 32 bytes válidos
+    using var sha256 = SHA256.Create();
+    var keyBytes = sha256.ComputeHash(Encoding.UTF8.GetBytes(_key));
+    _key = Convert.ToBase64String(keyBytes);
+  }
+
+  public string Encrypt(string plainText)
+  {
+    if (string.IsNullOrEmpty(plainText)) return plainText;
+
+    var key = Convert.FromBase64String(_key);
+    using var aes = Aes.Create();
+    aes.Key = key;
+    aes.GenerateIV(); // Generar vector de inicialización aleatorio
+
+    using var encryptor = aes.CreateEncryptor(aes.Key, aes.IV);
+    using var ms = new MemoryStream();
+
+    // Escribir el IV al principio del stream (necesario para desencriptar)
+    ms.Write(aes.IV, 0, aes.IV.Length);
+
+    using (var cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
+    using (var sw = new StreamWriter(cs))
+    {
+      sw.Write(plainText);
+    }
+
+    return Convert.ToBase64String(ms.ToArray());
+  }
+
+  public string Decrypt(string cipherText)
+  {
+    if (string.IsNullOrEmpty(cipherText)) return cipherText;
+
+    try
+    {
+      var fullCipher = Convert.FromBase64String(cipherText);
+      var key = Convert.FromBase64String(_key);
+
+      using var aes = Aes.Create();
+      aes.Key = key;
+
+      // Extraer el IV (los primeros 16 bytes)
+      var iv = new byte[16];
+      Array.Copy(fullCipher, 0, iv, 0, iv.Length);
+      aes.IV = iv;
+
+      using var decryptor = aes.CreateDecryptor(aes.Key, aes.IV);
+      using var ms = new MemoryStream(fullCipher, 16, fullCipher.Length - 16);
+      using var cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Read);
+      using var sr = new StreamReader(cs);
+
+      return sr.ReadToEnd();
+    }
+    catch
+    {
+      // Si falla al desencriptar (ej. porque el dato viejo no estaba encriptado),
+      // devolvemos el texto original para no romper la app en la migración.
+      return cipherText;
+    }
+  }
+}