To elaborate, I need help decompressing SCE (Sony Computer Entertainment) .pkg files. I've found several common patterns between multiple versions of the same file (released over the span of two years by Sony) using 010 Editor, but don't quite know what I'm looking at.

Here are the matches between two versions of 'package_data02.pkg', released two days apart:

The addresses and sizes of the matches enter image description here
The files use little endian and these are using ANSI character sets (I've looked at them using UTF-8 and Unicode as well)

I've discerned that the matches are part of the file structure, as their starting address and depth are shared across all ~300 .pkg files that have been released over the past two years.

My question is this: can I use the information I've gathered so far to find a way to decompress the data in the .pkg? (If it helps, I'm hoping to find either an executable or .c source files)

About the originally posted question:

I originally was asking for a way to use the hex dumps to exploit my way through AES encryption, and later found out that not only were the .pkgs only compressed, but I also had access to the encryption keys. Oops...

  • 1
    Why do you think its encrypted? Please provide more details about the file. A sample could be helpful.
    – NirIzr
    Sep 4 '16 at 0:20
  • I need to update this, as the files are purely compressed - the reason I though they were encrypted due to lack of knowledge and a poor assumption that Sony likes encrypting everything. I'll try to get a sample hex dump of one of the packages into the post
    – JRM
    Sep 5 '16 at 14:46
  • You should try understanding the header values. Mapping out each field there. Be aware that diagnosing compression algorithms is usually not an easy task. Especially if you're not familiar with compression related ideas and common schemes.
    – NirIzr
    Sep 5 '16 at 20:58
  • Thanks, I've been learning as I go, given this is my first time trying anything like this
    – JRM
    Sep 6 '16 at 16:22

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