This semester, we have a lecture called IT Security by a guy, who absolutely know his subject.
Nevertheless, he wanted to show us that sha256 is broken by an existing collision. (Google that, fellow ranters!)
There are two pdf files by google researchers, that show the caption „SHAttered“ both on different backgrounds, although they give the same SHA-hash.
He then tried to share us these two files by moodle and wondered, why he uploaded the same file twice.
Guess what happened? The moodle backend checks new uploaded files for their ... hash ... and then decides, weather to upload or the file is already existing. So, it did just a new symlink to the old file.
Ironic, that an exercise, that should show us sha collision failures on sha collision 😃