Crops solution:

morse code for the dots that had been changed (the reader is left to figure out what is a dash and what is a dot)
$!!!!!$!@@@!$!!!!!$@!$!@@@!$@!!!!$!!!!!$!@@@$@!$!@@@$!@!!$@!$!@@@!$@@@!!$!@@@@$@!!$!!!$@!!$@@!!@$

this translated into: 0-0A-10BABYA-36WOWĐ

someone managed find the "Wow! signal" wikipedia page with google fu that presumably involved the 'WOW' and something about crop circles or aliens. the wiki page prominently features a zoomed-in version of the wow image

several of us figured out that hashing '6EQUJ5' worked as a password for the 7z, and most of us were probably all startled that it worked.