This tool decrypts the 3DS cart encryption example on [3dbrew](https://3dbrew.org/wiki/Gamecards).
The code is based on code found on [GBATEK](https://problemkaputt.de/gbatek.htm#3dscartridgeregisters) (**Warning:** big page).
It expects a file named `0004000000038c00.3ds` in the current directory. A known-good dump of this title (LEGO Star Wars III The Clone Wars, EUR) has SHA-256 8fcbd4b394f765cb09f81ee7c62802d490c86ed85bd5ab3923b48a4d0222de22.
It assumes gamecart ID2 == 0, which should be the case for all retail carts.
Secrets
-------
To use this, you need a file called `ctr_secrets.py` in the directory where `cart.py` is. It needs to define a few things:
It needs to define `KEY_DERIVATION_CONSTANT` as an integer (`0x1##############################a`).
It needs to define `CART_KEYS` as an array or tuple like this:
CART_KEYS = ( # indexed based on ID2
{
'rc4': 0x4##############################7,
'snow': 0xd##############################4
},
{
'rc4': 0x3##############################9,
'snow': 0xd##############################4
},
{
'rc4': 0x0##############################0,
'snow': 0x0##############################0
},
{
'rc4': 0x7##############################c,
'snow': 0x0##############################a
}
)
Note that these are *integers*.
It needs to define an array or tuple `BOOTROM_KEYS` like this:
