Word out on the ‘net is that the iPhone’s “secret’ SDK key has been leaked to the general public. The SDK key is the digital signature that allows iTunes to verify the validity of a given application. As we already know, Apple has said that they will need to electronically verify and sanction any 3rd party application destined for the iPhone. If developers can figure out how to include this newly leaked key in their homebrew apps, however, we could see 3rd party software installation without the need for Apple’s blessing (and without Apple’s pay-per-app scheme). No word on just how this leaked, but anyone interest should hit the link for more info on the key itself, or take a long hard look at the image above.