Encrypting save games

Why?

Because the world today is not the world of yesterday. A capitalist oligarchy runs the world and forces us to consume in order to keep the gears of this rotten society on track. As such, the biggest market for video game consumption today is the mobile one. It is a market of poor souls forced to compulsively consume digital content in order to forget the misery of their every day life, commute, or just any other brief free moment they have that they are not using to produce goods or services for the ruling class. These individuals need to keep focusing on their video games (because not doing so will produce them a tremendous existential angst), so they go as far as spending money on them to extend their experience, and their preferred way of doing so is through in-app purchases and virtual currency.

But, imagine if someone was to find a way to edit the saved games and assign the items and currency without effort? This would be terrible, because it would help players consume the content much faster, and as such run out of it sooner than expected. If this happens they will have nothing that avoids them to think, and the tremendous agony of realizing their own irrelevance would again take over their life.

No, we definitely do not want this to happen, so let’s see how to encrypt savegames and protect the world order.

How?

The class File can open a file at a location and read/write data (integers, strings and variants). It also supports encryption. To create an encrypted file, a passphrase must be provided, like this:

var f = File.new()
var err = f.open_encrypted_with_pass("user://savedata.bin", File.WRITE, "mypass")
f.store_var(game_state)
f.close()
var f = new File();
var err = f.OpenEncryptedWithPass("user://savedata.bin", (int)File.ModeFlags.Write, "mypass");
f.StoreVar(gameState);
f.Close();

This will make the file unreadable to users, but will still not prevent them sharing save files. To solve this, use the device unique id or some unique user identifier, for example:

var f = File.new()
var err = f.open_encrypted_with_pass("user://savedata.bin", File.WRITE, OS.get_unique_id())
f.store_var(game_state)
f.close()
var f = new File();
var err = f.OpenEncryptedWithPass("user://savedata.bin", (int)File.ModeFlags.Write, OS.GetUniqueId());
f.StoreVar(gameState);
f.Close();

Note that OS.get_unique_id() only works on iOS and Android.

This is all! Thanks for your cooperation, citizen.