What if you could buy a movie once, and play it on a variety of different devices, without paying extra and without breaking any rules? That's the idea behind Keychest, a new digital initiative from Walt Disney Studios Home Entertainment.

According to The Wall Street Journal, the new movie distribution mechanism would use a "digital cloud" principle, similar to Google Docs. Google allows you to load photos, spreadsheets and other documents to an online server. Once it's up, you can access it from anywhere, without your home or office computer.

The Keychest concept would work similarly, except that when you make that purchase, you would receive a digital "key" or password. Once you enter the code, you could potentitally unlock access to your purchase anytime, anywhere, and on almost any device.

So instead of just making a simple purchase of a disc or other piece of physical media, you could also have rights to that media. That means while you're enjoying Pirates of the Caribbean on the big screen in the living room, the kids can watch it on an iPod or cell phone, while your spouse streams it to a tiny TV in the bedroom. It could even extend to online movie subscriptions.

The devices and services linked to your purchase would probably depend on Disney's partners, who have not been announced yet. The rumor is that the House of Mouse has already been showing off the concept, trying to get strength in studio and technology partners. Some of those hopefuls are supposedly also involved with Sony's competing Digital Entertainment Content Ecosystem.

"Keychest" sounds a bit more catchy -- but so did HD DVD. Whether or not this type of technology could save sinking home video sales remains to be seen. However, it looks like we may see another format war brewing soon, but this one played out in the ethereal regions of cyberspace, instead of with shiny silver discs. If all goes well, Disney could start marketing Keychest to consumers in 2010.