Just tried the Freedom app on our application and I could bought every in app purchase item with it. At least when running the Play Store 3.x. If I upgraded the play store to 4.x than the Freedom hack stopped working.
Anyhow, is there a way to protect against it?
Check the orderId returned. Correct orderIDs are of the form: [merchant ID].[actual order ID] Find your merchant ID in your Wallet account (last line on order page) and check in your app if it's the same. As the Freedom hack cannot by any means know your Wallet ID, the returned ID of hacked payments differs. Just refuse those payments.
Note that this is just an assumption. I am currently not 100% sure if this works. Feedback would be appreciated.
来源：https://stackoverflow.com/questions/16277467/protection-from-freedom