> The algorithm is public

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.

In their defence, in Section 15 of the FOI rejection letter, they mention the software is used for several fee-for-service industrial elections.

They still have copyright on the software: copying it and, say undercutting the AEC on the fee-for-service would be illegal. Far more likely that the AEC don't want to have their software open to scrutiny by politically-motivated geeks.

"Under the Fair Work (Registered Organisations) Act 2009 (the Act), the AEC must conduct all elections for office in registered organisations unless an exemption has been granted by the Fair Work Australia." http://election.aec.gov.au/About_AEC/AEC_Services/Industrial...

So they have a protected monopoly for that too?

Yes, it's a government... it grants and enforces monopolies.

Isn't that a conflict of interest? I mean, who or what pays for the development of the implementation?

I'm uneasy about that... presumably they get funded from our taxes. I'd have to guess any profit they make is put back into the pockets^w system, but not responding to FOI's on the basis of a commercial interest strikes me as weird.

Must be some impressive VB coding in any case.