C# AES encryption and decryption example

aes.cs

public static class AES
{
  // Keys should be 32 bytes
  public static string Encrypt(string text, byte[] key)
  {
    using (var memoryStream = new MemoryStream())
    using (var aes = Aes.Create())
    using (var encryptor = aes.CreateEncryptor(key, aes.IV))
    {
      memoryStream.Write(aes.IV, 0, aes.IV.Length);

      using (var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
      {
        using (var streamWriter = new StreamWriter(cryptoStream))
        {
          streamWriter.Write(text);
        }

        return Convert.ToBase64String(memoryStream.ToArray());
      }
    }
  }

  public static string Decrypt(string cipherText, byte[] key)
  {
    var cipherTextBytes = Convert.FromBase64String(cipherText);

    using (var memoryStream = new MemoryStream(cipherTextBytes))
    using (var aes = Aes.Create())
    {
      var initialState = new byte[aes.BlockSize / 8];
      memoryStream.Read(initialState, 0, initialState.Length);

      using (var decryptor = aes.CreateDecryptor(key, initialState))
      {
        using (var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
        {
          using (var streamReader = new StreamReader(cryptoStream))
          {
            return streamReader.ReadToEnd();
          }
        }
      }
    }
  }
}