diff --git a/tools/test_modules/m13500.pm b/tools/test_modules/m13500.pm
new file mode 100644
index 000000000..41490d46c
--- /dev/null
+++ b/tools/test_modules/m13500.pm
@@ -0,0 +1,62 @@
+#!/usr/bin/env perl
+
+##
+## Author......: See docs/credits.txt
+## License.....: MIT
+##
+
+use strict;
+use warnings;
+
+use Digest::SHA qw (sha1_hex);
+use Encode;
+
+sub module_constraints { [[0, 255], [-1, -1], [0, 16], [-1, -1], [-1, -1]] }
+
+sub get_pstoken_salt
+{
+  my $pstoken_length = random_number (16, 255);
+
+  ## not a valid pstoken but a better test
+  ## because of random length
+
+  my $pstoken_const = random_bytes ($pstoken_length);
+
+  return unpack ("H*", $pstoken_const);
+}
+
+sub module_generate_hash
+{
+  my $word = shift;
+  my $salt = shift;
+
+  if (length $salt == 0)
+  {
+    $salt = get_pstoken_salt ();
+  }
+
+  my $hash_buf = sha1_hex (pack ("H*", $salt) . encode ("UTF-16LE", $word));
+
+  my $hash = sprintf ("%s:%s", $hash_buf, $salt);
+
+  return $hash;
+}
+
+sub module_verify_hash
+{
+  my $line = shift;
+
+  my ($hash, $salt, $word) = split (':', $line);
+
+  return unless defined $hash;
+  return unless defined $salt;
+  return unless defined $word;
+
+  my $word_packed = pack_if_HEX_notation ($word);
+
+  my $new_hash = module_generate_hash ($word_packed, $salt);
+
+  return ($new_hash, $word);
+}
+
+1;