What if we split of the data into chunks? Let's say I have enough digits of PI stored that guarantees any chunk of x characters is found in there. Now, I encrypt my file that is k * x in size with k indices into pi. May possible improve if we use variable size chunks too. Would this not provide pretty good compression ratios?
Compression may be slow, though it'd be sped up if you can the precomputed digits of pi (and maybe even some prebuilt prefix datastructure of some sort?).
Decrypting, you can use the BBP formula so you wouldn't need all the digits of pi (though having the database would speed it up quite a bit).
Anyone have any sort of rough estimate on how this would perform in speed and compression ratio?