Constructor (2017) .FIL archives header decryption

[Siberian GRemlin]

Good Day.

Looks game uses some kind of cycled XOR encription for archives header. I found some regularity and tryed to rebuild xor sequence, but no luck with bytes different from zero.

Code: Select all

  xo1:=$d9;
  for k:=0 to $FF do begin
    cryp[k]:=xo1;
    if k mod 2=1 then xo1:=xo1-1;
    if k mod 8=0 then xo1:=xo1+$B;
    if k mod 8=2 then xo1:=xo1+$3;
    if k mod 8=4 then xo1:=xo1-$5;
    if k mod 8=6 then xo1:=xo1+$3;
    if k mod 16=7 then begin
      if ((k shr 4) mod 4)=0 then xo1:=xo1-$30-$10;
      if ((k shr 4) mod 4)=2 then xo1:=xo1+$50-$10;
    end;
  end;

Can anybody help with decryption? Free Demo available on Steam http://store.steampowered.com/app/619760/

Seems first value in header is file count, after that goes 0x30 bytes blocks for each file, that contained padded filename, offset and size.

Raw archive.


False decrypted header.

[Gano]

Maybe the following help:
https://github.com/shlainn/game-file-fo ... .FIL-files

and: https://github.com/jimmypw/constructor-fil

[aluigi]

Yes, useful information but it's an old format (*.fil) and a slightly different encryption (cn.ini).
Script:
http://aluigi.org/bms/constructor.bms

Please let me know if there is any problem with any FIL archive because I had to "guess" if the archive uses the old or new format.

[Gano]

FIL archives and cn.ini work without any problems. (Tested with my purchased game)
The TEXT.* files are not decrypted at least not as plain text.

[aluigi]

Can you upload a couple of these TEXT files?
There are no *.TEXT in the demo

[Gano]

Sure. Here you go

[Gano]

Any news ?

[aluigi]

I did just a "one minute" quick check by using the original obfuscation algorithm with different constants but no luck.
I have only updated the script to catch the "TEXT.*" files because the original script checked the "*.TEXT", anyway these files are NOT supported at the moment.

[odinboss]

Hi! I have a file ".fil". That I would like to unzip and recompress the files it contains(or is that I suppose).It contains files ".dat", ".bin", ".tiz" and others. It is a file from the year 1999. Is there any possibility of extracting the files?

http://www.mediafire.com/file/3681d0pmgcwg0c9/LUNADATA.FIL/file

[aluigi]

@odinboss
You are off-topic here because your files are from another game:
https://github.com/studio-lucia/lunarda ... ATA.FIL.md