private void OptionDecryptAES_Click(object sender, EventArgs e)
        {
            try
            {
                SymmetricCryptography decrypterAES = new SymmetricCryptography(true);
                string contentToDecrypt            = UploadedDocumentClass.GetFileContent();
                string decrypted = decrypterAES.DecryptDocumentAES(contentToDecrypt);

                LoadingScreenForm loadScreen = new LoadingScreenForm(UploadedDocumentClass.GetFileName(), "AES Decryption");
                loadScreen.ShowDialog();

                SaveToTxt("helpfile_aes_decrypted", decrypted);

                outputScreen.Text = "Decrypted with AES: \r\n" + decrypted;
            }
            catch
            {
                MessageBox.Show("Document is not valid AES encryption", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }