fuck this challenge, no interesting concepts, only tricky details

look into zsh source, sind out that RANDOM uses C srand / rand

srand is called on zsh init with epoch sec+usec seed

we can guess the seed, filter using known values and do trial decryptions
to find the right one

tricky detail: subshell does not modify the rand state of the parent shell
so in the encoded piece generation the random value does not change..
haha that did not cost me my sanity