It’s the hot button topic on the internet right now, but nobody really knows the answer to the burning question: where is the hack that will get Siri working on an iPhone 4?

We’ve seen video of it working thanks to chpwn and Steve Troughton-Smith, but the pair has been reluctant to make the hack available to us, the non-paying public.

In a blog post today, chpwn has sought to clear things up by explaining why the port hasn’t been made publicly available, and as we suspected, it all comes down to copyright…

In order to get Siri to work on an iPhone 4 right now, the files required need to be extracted either from an iPhone 4S or its firmware.

The issue there is quite obvious. If you already own an iPhone 4S, then the chances are you aren’t that bothered about making it work with your older hardware. If you don’t own one, you’re left fishing around in the IPSW file Apple provides. That isn’t quite as easy as it sounds.

Apple’s IPSWs are encrypted, and hackers do not currently have the decryption keys required to pull out all of the necessary Siri goodness.

This is where things start to become illegal. Hackers cannot share Siri’s code with people that do not own an iPhone 4S without breaking copyright law.

“..the firmware files are distributed encrypted, and we do not yet have the decryption key to access the Siri files inside of the iPhone 4S firmware file.

Just from that, you currently must already own an iPhone 4S to install Siri on it without a blatant copyright violation. But even that’s not all: if you do all of that, there’s still a few more reasons why Siri won’t just work.”

This all leaves us at something of a stalemate. Until the decryption keys are found for Apple’s IPSW files, Siri will not be made available to the public.

Even if that does happen, there are still technical reasons why Siri won’t just work on your iPhone 4, but neither Troughton-Smith nor chpwn are willing to go too far into that situation for fear of tipping their hat.

What this all boils down to is rather simple. Right now, and for the foreseeable future, if you want to use Siri, you need an iPhone 4S.