How is this javascript encoded? And how to decode it?

Question

JavaScript

How is this javascript encoded? And how to decode it?
Link to the file -  speedy.sh/9zPB7/application.js
Several mirrors to the same file:
www.sendspace.com/file/58naic
www23.zippyshare.com/v/2382129/file.html
PS: Sorry for the garbage hosting.
Thanks in advance!

Answer 1

In chrome inspector go to www.speedyshare.com or wherever it works. Look at the network traffic, and in upload_page.php we see the same code, only not obfuscated;)

Answer 2

Something tells me that this is not JS.

Answer 3

JS weighing 8.8 mb - it is extremely unlikely that there is JS, except that it contains the source code of the site with pictures, scripts and styles. See how this file is loaded and what happens to it.
Judging by the entropy of this file, it is not compressed and not encrypted with normal ciphers. Most likely this file is loaded, decoded and further processed in accordance with some logic. Look at it not as a JS file, but as some unknown file.

Answer 4

Since the presence of ciphertext tells you practically nothing about the encryption algorithm, and even more so about the key, then you have several options:
1. Cryptanalysis. Decrypt the text, having on hand the ciphertext and, possibly, the plaintext. Extremely labor intensive and costly. But there is a chance that an amateur encrypted it (since the file has increased 4 times) and you will be able to find a self-written encryption algorithm. You can ask on specialized forums.
2. Software analysis. You need to analyze the application that works with this file. By its behavior you will find the algorithm and possibly the key. Also look at the installer. There is also a possibility that this was done with the help of some well-known tool, you can dig there. Difficult, but possible.
3. Buy a software development company.
4.Bandit cryptanalysis (blackmail, extortion, thermorectal cryptanalysis)
As you can see, there are many options.