How to stop jailbreaking of android apps?

I have uploaded an 开发者_开发问答android app over Android Market. It is free and anyone can download it from the Market.It is downloaded over 100,000 times. And now i want to upload an updated version of that app. This time i want to charge $0.99 for each download. But i have a fear of jail-breaking. There are many websites offer paid apps of Android Market in free.

So, the question is how to stop this jail-breaking of android apps?

Thank you very much in advance.

And now i want to upload an updated version of that app. This time i want to charge $0.99 for each download.

You can't do that. You can offer a new app for $0.99, but you cannot make a free app be no longer free.

So, the question is how to stop this jail-breaking of android apps?

Use the LVL and hope for a fair amount of luck. Any license scheme can be cracked, but you may make it difficult enough that nobody will bother trying it for your app.

Or, choose a business model where you do not have to charge for the app.

No, there really isn't. Maybe have a license key like Launcher Pro, but even then I'm sure somebody will be able to bypass that.

Unfortunately, Google's LVL is simple to crack. http://www.readwriteweb.com/archives/android_drm_cracked_pirating_apps_is_easy.php