if {[catch {
        eval exec -success Success $openPgpInstalledCommand
      } result]} then {
        error "cannot use OpenPGP: may not be installed and/or configured"
      }
    } else {
      if {[catch {
        eval exec [subst $openPgpInstalledCommand]
      } result]} then {
        error "cannot use OpenPGP: may not be installed and/or configured"
      }
    }

    if {![info exists result] || \
        ![regexp -- $openPgpInstalledPattern $result]} then {