ZenHAX

Context: Phoenix Wright: Ace Attorney's sound files (.unity3d) are encrypted with Rijndael. I am able to successfully decrypt the file, modify it, and then I need to encrypt it again so the game will accept it.

I'm using this script (from https://www.zenhax.com/viewtopic.php?f=9&t=11186) to decrypt:

get NAME filename
encryption Rijndael "\x35\x38\x9A\xFF\xF2\x61\xB3\xE8\x87\x22\x24\x0B\x6B\x0B\x25\xC8" "\x01\x85\x40\xA5\x57\xDE\x8C\x4E\x86\xE4\x23\xE3\x3A\xB9\x77\x84"
get SIZE asize
log NAME 0 SIZE

To re-encrypt what I've decrypted, would I just run the same script on my output file again? (Doesn't seem like that works.) Or are there changes that need to be made to this script to be able to encrypt?

(If this thread would be a better fit under the "Help with QuickBMS & tools" forum, feel free to move this thread there.)

Just add 1 to the "encryption" instruction and it will encrypt the file:

get NAME filename
encryption Rijndael "\x35\x38\x9A\xFF\xF2\x61\xB3\xE8\x87\x22\x24\x0B\x6B\x0B\x25\xC8" "\x01\x85\x40\xA5\x57\xDE\x8C\x4E\x86\xE4\x23\xE3\x3A\xB9\x77\x84" 1
get SIZE asize
log NAME 0 SIZE

it doesn't work

Impossible.
It's a simple block-cipher encryption, indeed I already tested it: decrypt + encrypt = original