#!/usr/bin/perl
use strict;
use warnings;
#use MIME::Base64;
use URI::Escape;
use LWP::UserAgent;

#print base64ToText("lUcPBf9dfsxp_6VvTASlkbO462aWgXNwMOl00HyBlqTCZowPGR1l4i\"uxLkgseX0Sefqpmf7aCMRZd1kc8scScfIf8juFgxPup357nLOuVhsHlFqsU6SH9JPM\"RY\"4XKVOFd790u4G8UoxHAfrS4s52EzM7mcuNhfNfQRG7V98LRk8IcGGLvgwoxz0Nv48IchbHtLgN62kt\"tXd7_dhrYq3EP5m7Ax0nsbkksCQBhHIaIyKGJvSDejAsbkovRGgDGGbEul_v3aFhH2xbTnk01DN1DHwABeDCK9T7Xl9i3yK0H_aDOCQ00JvX_hWp3\"pAydZaX0UrqZDxwiY5aqUmKchQCSm7"),"\n";
#print decode_base64("lUcPBf9dfsxp+6VvTASlkbO462aWgXNwMOl00HyBlqTCZowPGR1l4i/uxLkgseX0Sefqpmf7aCMRZd1kc8scScfIf8juFgxPup357nLOuVhsHlFqsU6SH9JPM/RY/4XKVOFd790u4G8UoxHAfrS4s52EzM7mcuNhfNfQRG7V98LRk8IcGGLvgwoxz0Nv48IchbHtLgN62kt/tXd7+dhrYq3EP5m7Ax0nsbkksCQBhHIaIyKGJvSDejAsbkovRGgDGGbEul+v3aFhH2xbTnk01DN1DHwABeDCK9T7Xl9i3yK0H+aDOCQ00JvX+hWp3/pAydZaX0UrqZDxwiY5aqUmKchQCSm7"),"\n";


my ($text,$ob,$base_length)=@ARGV;
if ($text && $ob && $base_length) {
	#print uri_escape(&dec(&base64ToText($text),$ob,$base_length));
	print &dec(&base64ToText($text),$ob,$base_length),"\n";
} elsif ($text =~ /http:/) {
	my ($doc, $ret, $url, $name);

	$doc=&wget($text) || die "fetch $text";
	if ($doc =~ /new Array\(\);\w+=(\d+)[^']*?\w+='(\w+)'/s) {
		$base_length=$1;
		$ob=$2;
	} else {
		die "base_length or ob(fuscation) string not found";
	}
	if ($doc =~ /enc\(base64ToText\('([^']+)'/s) {
		$text=$1;
	} else {
		die "(cipher)text not found";
	}
	$ret=&dec(&base64ToText($text),$ob,$base_length);
	if ($ret =~ /href="([^"]+)">([^<]+)</) {
		$url=$1;
		$name=$2;
		print "getting $url\n(might take a while)\n";
		open O,">$name" || die "open $name";
		print O &wget($url) || die "wget/write";
		close O || die "close $name";
	} else {
		print $ret;
	}
} else {
	print <<"EOF";
$0: decode sendspace obfuscated urls
sendspace_dec.pl <ciphertext> <obstring> <length>
sendspace_dec.pl <url>

examples:
sendspace_dec.pl 'oogfcnUJCC87dTWtGrVsC8jlkaEboGYh9JMefmKoclAmbWUbPr"kFdCZt_9UUbtxi4muu8GfiMNae1VbYQTUIT2l9fOgNnE9bzydvKN_WOlvuBtGx0OmOsHfuymiCsB6asZdH7cph_xr3YLiHQR690kSNpK9o8EoCB749fay_gaY1XGBqzUefHjOGcfC5dBpnb8pG7xpAIlFoLTDTZkV26C82doBdj1ofgt"HZe6Ibd6G3lp9_E8RwOOsJEnBDKE2cvsN0eIQ1tb4zHORFz8UL3yuhldGtYYULZPGScU71z8pzY"zFM"br9mpabEn"_hjc3IlWQ1erwkiZpO3qecN1yRQjOB' b7Nxf 236
<a id="downlink" href="http://fs07n1.sendspace.com/dl/7b5de57b571a1bd6f35d5c54ac878b5d/45baa944/3hblgx/Axel Corti - Der Schalldämpfer - An Einem Wintermorgen vor Sonnenaufgang.mp3">Axel Corti - Der Schalldämpfer - An Einem Wintermorgen vor Sonnenaufgang.mp3</a>
sendspace_dec.pl http://www.sendspace.com/file/3hblgx
getting http://fs07n2.sendspace.com/dl/85aed4abf9bd2cdd7176a759896fffa8/45bab071/3hblgx/Axel Corti - Der Schalldämpfer - An Einem Wintermorgen vor Sonnenaufgang.mp3
EOF
}

sub dec($$) {
	my ($text,$ob,$base_length)=@_;
	my (@base_array, $i, $j, $k, $l, @ob_array, $out,$exc,$offset);
	for $i (0.. ($base_length-1)) {
		$base_array[$i]=$i; 
	}
	#ob='HGZNc';
	$k=0;
	@ob_array=@base_array;
	for $j (0.. ($base_length-1)) {
		$k=(unpack("C",substr($ob,$j%length($ob),1))+$ob_array[$j]+$k)%$base_length;
		$exc=$ob_array[$j];
		$ob_array[$j]=$ob_array[$k];
		$ob_array[$k]=$exc;
		$ob_array[$k]=$ob_array[$k]^5;
	}
	$out="";
	$k=0;
	for $l (0..(length($text)-1)) {
		$offset=$l%$base_length;
		$k=($ob_array[$offset]+$k)%$base_length;
		$exc=$ob_array[$offset];
		$ob_array[$offset]=$ob_array[$k];
		$ob_array[$k]=$exc;
		$out.=pack("C",unpack("C",substr($text,$l,1))^$ob_array[($ob_array[$offset]+$ob_array[$k])%$base_length]);
	}
	return $out;
}

sub base64ToText($)
{
	my $b64s='abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_"';
	my ($t)=@_;
	my $r='';
	my $m=0;
	my $a=0;
	my $c;
	for my $n (0..(length($t)-1)) {
		$c=index($b64s,substr($t,$n,1));
		if($c >= 0)
		{
			if($m) {
				$r.=pack("C",(($c << (8-$m))&255) | $a)
			}
			$a = $c >> $m;
			$m+=2;
			if($m==8) {
				$m=0;
			}
		} else {
			print substr($t,$n,1);
		}
	}
	return $r;
}

# par 1: url, (optional) parameter 2: content in case of POST request
sub wget($;$) {
	my ($request, $response, $success);

	my ($url,$content)=@_;

	my $ua = LWP::UserAgent->new;
	$request = HTTP::Request->new(GET => "$url");
	if ($content) {
		$request->method("POST");
		$request->content($content);
	}

	$success=0;
	while (!$success) {
		$ua->agent('Mozilla/5.0');
		$ua->timeout(2);
		# $ua->conn_cache($cache);
		$response = $ua->request($request);
		$success=$response->is_success;
	}
	return $response->content;
}