What is the different between Android signed certification vs a platform certification ?

What is the dif开发者_开发知识库ferent between Android signed certification vs a platform certification ?

Every application installed on an Android device needs to be signed with a certificate or the emulator/device will refuse to run it.

During testing/debugging the Android tools will automatically create a test certificate and sign the app with it when deploying to the emulator or a physical device. For releases e.g. to the Android market the developer has to create a certificate and use it to sign the app; using the same certificate to sign updates to an app allows Android devices to recognize it being from the same developer.

Applications signed with a platform certificate can obtain additional privileges, e.g. rebooting, shutting down or even bricking a phone.

On unrooted (retail) Android phones, there is usually no way to sign your own application with a platform certificate as these are kept private by OEMs (Samsung, HTC, etc.) or Google. On rooted phones, you can install a custom ROM with a platform certificate of your own and also sign apps with that -- with all the consequences.