private void enc_btn_rsa_Click(object sender, EventArgs e)
 {
     if (check_file_rsa == true)
     {
         rsa_enc_path         = rsa.Encrypt_File(message_rsa.Text);
         enc_message_rsa.Text = rsa_enc_path;
     }
     else
     {
         rsa_enc_message      = rsa.Encrypt(message_rsa.Text);
         enc_message_rsa.Text = rsa_enc_message;
     }
 }