This isn’t as weird an idea as I had anticipated would crop up in my efforts to solve K4.  It’s also not something I would have imagined four months ago.

It’s on par with a one-time pad or stream cipher but is more simplistic because the algorithm is well known and relatively easy to derive.

Take the digits of pi and use modular arithmetic on the K4 letters-as-digits.  Take the resulting numbers and convert them back to letters.  Take those letters and do a little frequency analysis, a little simple substitution and see what you get.

pi PRNG analysis

It gets a bit wordy but if you skip halfway through it might help.

It also didn’t work out as smashingly well as I’d hoped.

I like the idea though and may try it again with some different simple PRNG’s.