The is a fixed, 16-byte (128-bit) AES-128 encryption key. It is identical across every single Nintendo Wii console ever manufactured.
Place it in the root folder of your application (e.g., the main Cemu folder). Extracting Your Own Key wii common key
A "Common Key" is a cryptographic value used by Nintendo consoles—most notably the —to decrypt system content and software The is a fixed, 16-byte (128-bit) AES-128 encryption key