decrypt it with its key. there was a site with the keys for each game, gut it kept changing to avoid nintendo. you can decrypt them with uwizard. google the common key+. the internal keys for the wii u are easy to find, but I don't know about wud keys though since each game (think even region) is different. uwizard has the keys embedded with a sha-1 to check if the key is correct. afaik, there's no way to reverse the sha-1.