(12-10-2022, 09:42 PM)rufaswan Wrote: Actually @bihaiorg already posted the solution, the code from 52pojie.cn looks very complex, but it can be simplified to
Code:if ( v10 == *(_QWORD *)"VEGATOPJOY000000VEGATOPJOY000000N7cocos2d5ImageE" )
{
v33 = v10;
v34 = v9;
v35 = v11;
v3 -= 16;
v12 = v4[23];
v4 += 16;
*v4 ^= 0x51u;
v4[1] = v4[1] ^ 0x49;
v4[2] = v4[2] ^ 0x51;
v4[3] = v4[3] ^ 0x49;
v4[4] = v4[4] ^ 0x41;
v4[5] = v4[5] ^ 0x4E;
v4[6] = v4[6] ^ 0x52;
v4[7] = v12 ^ 0x41;
v4[8] = v4[8] ^ 0x4E;
v4[9] = v4[9] ^ 0x58;
v4[10] = v4[10] ^ 0x49;
v4[11] = v4[11] ^ 0x41;
v4[12] = v4[12] ^ 0x4F;
v4[13] = v4[13] ^ 0x42;
v4[14] = v4[14] ^ 0x45;
v4[15] ^= 0x49u;
}
What the code basically means - check the first 16 bytes for "VEGATOPJOY000000", then XOR the next 16 bytes with "51 49 51 49 41 4e 52 41 4e 58 49 41 4f 42 45 49". That is the ASTC image header. The rest are ASTC image data, and they are unencrypted..
Re-save the ASTC image part as *.ASTC file, and you can use this tool to convert them
https://github.com/ARM-software/astc-encoder/releases
Run in command line like this
Code:astcenc-sse2.exe -dl IN.ASTC OUT.PNG
The tool can also encode the edited PNG back. Just XOR the ASTC header, and then prepend "VEGATOPJOY000000" back to the file. It's very easy.
Thanks for @bihaiorg for figured the whole thing out and sharing the code!
- Rufas
Ok so, I followed these steps and I ran into an issue.
I opened a png file named '1e3b42733ae3dbc38cc643206a9376fd' in the '1e' folder from the assets > release directory in wxHexEditor and deleted the first 16 bytes.
I use XOR on the next 16 bytes, then save the file as .astc.
When I run the command to convert it to PNG, I get a message saying 'ERROR: Unknown compressed input file type'.
What could I be doing wrong? Please bare with me, I am fairly new to this. Perhaps a short video tutorial could be of some use.
By the way, would that same key be used to XOR all the other encrypted images?