No clue, but these were mentioned
here a while back. I have not nailed down the maker, but these appear to mainly sit on the hitch, but use the hinges for additional support.
This is fairly inexpensive, but it provides decent security, and one can get a canvas bag to put inside... or buy
both. Some plastic carriers might be able to be wiggled open, while this locking carrier will require some definite use of a crowbar or bolt cutters in order to get to the stored contents inside. (Assuming one is using a locking hitch pin... without that, all bets are off.)