[Paradox]

I re-wrote blurg's python script and changed a few K-S-V's php script (thanks to them), to get automatically the constants and the start variable.

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import os, urllib, datetime, time, re

dirName = os.path.dirname(os.path.abspath(__file__))
mulutibuFile = "mulutibu_v4_3.swf"

command = "ffdec -export script \"%s\" %s" % (dirName, mulutibuFile)
os.system(command)

time.sleep(10)

with open(dirName + "\\com\\longtailvideo\\plugins\\mulutibu6\\Mulutibu.as", "r") as startFile:
	start = re.findall("d1\([0-9]{2}\)", startFile.read())

	command = "ffdec -export binaryData \"%s\" %s" % (dirName, mulutibuFile)
	os.system(command)

	time.sleep(10)

	with open(dirName + "\\31.bin", "r") as fo:
		binary = fo.read()

		phpFile	= '''<?php
	if ( $argc < 2 )
		die( "Usage: php adn.php <encrypted_subtitles>" );

	// Read encrypted subtitles
	$file = file_get_contents( $argv[1] );
	$file = base64_decode( $file );

	// Get decryption key from aes constants
	$constants = "{CONSTANTS}";
	$start     = {START};
	$key       = substr( $constants, $start, 32 );
	$salt      = substr( $file, 8, 8 );
	$key       = $key . $salt;
	$hash1     = md5( $key, true );
	$hash2     = md5( $hash1 . $key, true );
	$iv        = md5( $hash2 . $key, true );
	$key       = $hash1 . $hash2;
	// Decrypt subtitles
	$td = mcrypt_module_open( "rijndael-128", "", "cbc", "" );
	mcrypt_generic_init( $td, $key, $iv );

	$decrypted = mdecrypt_generic( $td, $file );
	$decrypted = substr( $decrypted, 32 );
	mcrypt_generic_deinit( $td );
	mcrypt_module_close( $td );

	// Detect and remove PKCS#7 padding
	$padded = true;
	$len    = strlen( $decrypted );
	$pad    = ord( $decrypted[$len - 1] );

	for ( $i = 1; $i <= $pad; $i++ )
		$padded &= ( $pad == ord( substr( $decrypted, -$i, 1 ) ) ) ? true : false;
	if ( $padded )
		$decrypted = substr( $decrypted, 0, $len - $pad );

	// Save decrypted subtitles
	$file = pathinfo( $argv[1], PATHINFO_FILENAME ) . ".ass";
	file_put_contents( $file, $decrypted );
?>'''
		phpFile = re.sub("\{CONSTANTS\}", binary.replace("0x", "\\x").strip(), phpFile)
		phpFile = re.sub("\{START\}", re.findall(r"\d+", start[0])[1], phpFile)

		with open("adn.php", "w") as out:
			out.write(phpFile)

Assuming you will save the script as adn.py, put :

 
adn.py

in your console and it will generate an adn.php file, then put:

 
php adn.php "picture_file"

P.S : You will need to get the picture file using fiddler.
P.S2 : When you finish, delete : 31.bin, mulutibu6.as and mulutibu_v4_3.swf files. Delete also com and mx folders.
P.S3 : Be sure to have the path of the JPEXS Free Flash Decompiler folder in your environment path variable, e.g : C:\Programe Files\FFDec

Hope it helps !

EDIT : You MUST download the mulutibu file with fiddler or from your browser to get the valid file and rename it to mulutibu_v4_3.swf, then put it in the same folder as adn.py and run the script !