Origin's par-file

[Haoose]

Hi.
This is a script for par-files from games in Origin.

Code: Select all

get ID long
if ID == 1007747626
	set POS 0
else
	set POS 4
endif

encryption XOR "q@pO3o#5jNA6$sjP3qwe1"
get SIZE asize
math SIZE -= POS
log "decrypted_par.txt" POS SIZE

Does anyone know assignment of first 4 bytes of par-file?
Most likely it is a checksum.

[Ekey]

here

[Haoose]

Origin PAR Tool by Ekey (h4x0r) & Haoose

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https://cloud.mail.ru/public/5ctW/2WVSRg3C5
http://sendfile.su/1529805
https://mega.nz/#!FXZkAAST!vKSD505ohUn_wIavonqzVLKa736Ot5ZwRKm73Riunx0

Open - decode par-file
Patch - patching par-file for use game in offline mode (removes the substring "RequiredToPlayV1,")
Save - encode par-file

Enjoy

[mirh]

You may want to check this.
It only results in gibberish in your tool.

[HammerTank]

How are the first 4 bytes calculated actually? Can anyone tell?

[Puterboy1]

No, but I’ll bet it’s distinctive...that is I feel there have been others that have tried before to extract the files from the game.

[HammerTank]

Hmm, sadly none of the creators is reachable anymore.

[Ekey]

How are the first 4 bytes calculated actually? Can anyone tell?

This is CRC32 of encrypted data

Hmm, sadly none of the creators is reachable anymore.

What you mean?

[HammerTank]

This is CRC32 of encrypted data

It doesn't seem to be CRC32. I already checked that. That's why I'm asking.
I took a par file, removed the first 4 bytes and the CRC32 doesn't match the hash I removed before.

[Ekey]

Make sure your CRC32 algorithm works with polynomial 0x04C11DB7

[HammerTank]

Make sure your CRC32 algorithm works with polynomial 0x04C11DB7

I used that. Look at the file I attached. The checksum in the file is 0x31E360B3, but when I calculate the CRC32, I get 0xBDC63D58 (polynomial 0x00000000) or 0xDCB13237 (polynomial 0x04C11DB7). So what's wrong? I don't get it.

RA95Launcher.zip

[HammerTank]

Noone?

In your tool, the following two different contents result in the same checksum. So this is obviously no CRC32 as it would also change with every byte that changed...

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[Base]
ContentId = 1001288
ProductTitle = "Command and Conquer Red Alert"
InstalledDistro = RequiredToPlayV1,AccessDigitalV3
SupportedDistros

Code: Select all

[Base]
ContentId = 1001288
ProductTitle = "Command and Conquer Red Alert"
InstalledDistro = RequiredToPlayV1,AccessDigitalV4
SupportedDistros

But both these contents result in the same checksum with your tool. Can you please explain?

[HammerTank]

Sadly, noone is willing to help, right?

[mirh]

See these previous analysis
https://forum.exetools.com/showthread.php?t=17472
https://yingtongli.me/blog/2018/11/16/drm1-1.html
https://github.com/ME3Explorer/ME3Explo ... /PAREditor

[HammerTank]

See these previous analysis
https://forum.exetools.com/showthread.php?t=17472
https://yingtongli.me/blog/2018/11/16/drm1-1.html
https://github.com/ME3Explorer/ME3Explo ... /PAREditor

Thank you very much. The second link did it with the hint that only every 4th byte is used.