A moderatly safe save system can be created in a couple of hours from scratch. Features of such a system include name protection (case insensitive), high efficency (even complex save codes could be loaded and generated within under a frame) and checksum protection.
You would need more time for order encoding or scrambling (make it look more random).
However it still is more than enough for safish saving and loading (no one is going to manually crack the codes any time soon).
The principles are simple, you convert integers (representing what you want to save) into higher base code (usually around the base 64) and store that as strings of a fixed width. Each time you do that, you hash the value and add that to a global hash (as well as the hash of the player name (lower or upper cased to make sure its case insensitive as you can change case without making new accounts). Finally encode that and your done.
Decoding is just the opposite, I advise some form of lookup table though for speedier decoding of characters.
