so right now, as you may have seen, the swing thread is free while encripting so it can resize without problems, even more, you can do file ad text at the same time. however, it would be nice to disable the button while the algorithm is working and re-enable it when it's done. and also if you want to go fancy, add a progress bar
as for the algorithm itself, i don't know what's wrong but it takes +10 min to go through a 170MB file