diff --git a/build/check_certificate.pl b/build/check_certificate.pl
index eab84b2d..e59e3b2f 100755
--- a/build/check_certificate.pl
+++ b/build/check_certificate.pl
@@ -15,7 +15,7 @@
 
 while (@ARGV) {
 	$fn = shift @ARGV;
-	open(IN, $fn);
+	open(IN, $fn) || die "could not open $fn: $!";
 	print PIPE "Entity: $fn keyname (none)\n";
 	while (<IN>) {
 		print PIPE $_;
@@ -23,4 +23,4 @@
 	close IN;
 }
 
-close PIPE;
\ No newline at end of file
+close PIPE;