digest.pl

#!/usr/bin/perl

use strict;
use warnings;
use Digest::SHA1 qw/sha1_hex/;
use Digest::MD5 qw(md5 md5_hex md5_base64);
use Data::Dumper;

my @ascii = map {pack 'C', $_} ord('a')..ord('z');
push @ascii, ('-', '_');
push @ascii, (0..9);

for my $length (0..10) {
  print "length is $length\n";
  my $nestfor = sub { nestfor(\@ascii, $_[0], $_[1]); };
  # seed.
  my $subref = sub {
    my $h = shift;
    my $url = "http://vulnerability.jp/$h.html";
    if (sha1_hex($url) eq 'e5877ebe3560be14d35c6eb96ffa38fee97078f0') {
      print "Answer is $url\n";  
      exit;
    }
  };

  # wrap.
  if ($length != 0) {
    $subref = gen($subref) for 1..$length;
  }

  # Run.
  $nestfor->($subref, '');
}

sub gen {
  my $s = shift;
  return sub {nestfor(\@ascii,$s,shift)};
}

sub nestfor {
  my $ary = shift;
  my $sub = shift;
  my $bind = shift || '';
  $sub->("$bind$_") for @$ary;
}