- optional<dcp::EncryptedKDM> kdm;
- try {
- kdm = _film->make_kdm (
- Config::instance()->decryption_chain()->leaf(),
- vector<string>(),
- dialog.cpl(),
- from, to,
- dcp::Formulation::MODIFIED_TRANSITIONAL_1,
- true,
- 0
- );
- } catch (dcp::NotEncryptedError& e) {
- error_dialog (this, _("CPL's content is not encrypted."));
- } catch (exception& e) {
- error_dialog (this, e.what ());
- } catch (...) {
- error_dialog (this, _("An unknown exception occurred."));
+ auto signer = Config::instance()->signer_chain();
+ if (!signer->valid()) {
+ error_dialog(this, _("The certificate chain for signing is invalid"));
+ return;