I am at a point where I probably miss something important. The files placed at the obvious locations contain one half needed for a "two part communication". However, to my knowledge it is not the required part to initialize this connection but to accept it. The algorithm itself for the given key length is not reversible in realistic times. The implementation of openssh is up to date (not the old D****n one). The title seems to point to Z's account. He also has group permissions for the level user. However, you would need to have user permissions anyway. I cannot "find" any more files belonging to z or level8 which are readable by me.
Did a file disappear from the server or am I just missing something?
€: Changed a bit in order not to spoil too much