Change hash mode of addition, add test module

Changed pbkdf2-sha512 Perl passlib hash module hashmode to 20200
(assigned by maintainer)

Added test module for 20200 module

tools/test_modules/m20200.pm

@@ -0,0 +1,88 @@
+#!/usr/bin/env perl
+
+##
+## Author......: See docs/credits.txt
+## License.....: MIT
+##
+
+use strict;
+use warnings;
+
+use Crypt::PBKDF2;
+use MIME::Base64 qw (encode_base64 decode_base64);
+
+sub module_constraints { [[0, 256], [-1, -1], [-1, -1], [-1, -1], [-1, -1]] }
+
+sub module_generate_hash
+{
+  my $word = shift;
+  my $salt = shift;
+  my $iter = shift // 1024;
+
+  if (length $salt == 0)
+  {
+    $salt = random_bytes (16);
+  }
+
+  my $pbkdf2 = Crypt::PBKDF2->new
+  (
+    hasher     => Crypt::PBKDF2->hasher_from_algorithm ('HMACSHA2', 512),
+    iterations => $iter
+  );
+
+  my $hash_buf = encode_base64 ($pbkdf2->PBKDF2 ($salt, $word), '');
+  my $salt_buf = encode_base64 ($salt, '');
+  
+  # replace + with .
+  $hash_buf =~ s/\+/\./g;
+  $salt_buf =~ s/\+/\./g;
+  
+  # remove padding =
+  $hash_buf =~ s/\=+$//;
+  $salt_buf =~ s/\=+$//;
+  
+  my $hash = sprintf ("\$pbkdf2-sha512\$%i\$%s\$%s", $iter, $salt_buf, $hash_buf);
+
+  return $hash;
+}
+
+sub module_verify_hash
+{
+  my $line = shift;
+
+  # check signature
+  return unless (substr ($line, 0, 15) eq '$pbkdf2-sha512$');
+
+  # get hash
+  my $index1 = index ($line, '$', 15);
+
+  return if $index1 < 1;
+
+  my $index2 = index ($line, '$', $index1 + 1);
+
+  my $iter = substr ($line, 15,  $index1 - 15);
+
+  my $salt = substr ($line, $index1 + 1,  $index2 - $index1 - 1);
+
+  $index1 = index ($line, ':', $index2 + 1);
+
+  return if $index1 < 1;
+
+  my $word = substr ($line, $index1 + 1);
+
+  return unless defined $salt;
+  return unless defined $iter;
+  return unless defined $word;
+
+  $word = pack_if_HEX_notation ($word);
+
+  # fix salt from 'alternate' to 'ordinary' base64 encoding before
+  $salt =~ s/\./\+/g;
+  $salt .= '==';
+
+  my $new_hash = module_generate_hash ($word, decode_base64($salt), $iter);
+
+  return ($new_hash, $word);
+}
+
+1;