Added back easter egg, because why not.

tutorials/io/encrypting_save_games.md

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+
+# 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 everyday 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 fill them with
+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 what if someone were to find a way to edit the saved games and
+assign the items and currency without effort? That would be terrible,
+because it would help players consume the content much faster, and therefore
+run out of it sooner than expected. If that happens, they will have
+nothing that prevents them from thinking, and the tremendous agony of realizing
+their own irrelevance would again take over their life.
+
+No, we definitely do not want that 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()
+```
+
+This will make the file unreadable to users, but will still not prevent
+them from sharing savefiles. 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()
+```
+
+
+Note that `OS.get_unique_id()` does not work on UWP or HTML5.
+
+That is all! Thank you for your cooperation, citizen.
+
+note:
+
+This method cannot really prevent players from editing their savegames
+locally because, since the encryption key is stored inside the game, the player
+can still decrypt and edit the file themselves. The only way to prevent this
+from being possible is to store the save data on a remote server, where players
+can only make authorized changes to their save data. If your game deals with
+real money, you need to be doing this anyway.