The algorithm is public. It's the Australian Electoral Commission's implementation of it, their software, that's used in public elections that they're calling a trade secret.
Clearly so -- except the AEC explicitly say "The algorithm is the trade secret."[1] Which to me says they don't know what algorithm means.
[1]: http://easycount.mjec.net/2013-12-09-aec-to-mjec.pdf at paragraph 57.
So they have a protected monopoly for that too?
Must be some impressive VB coding in any case.