All Android applications must be signed before they are allowed to be deployed onto a device (or emulator). Unlike other mobile platforms, you need not purchase digital certificates from a certificate authority (CA). Instead, you can generate your own personal certificate and use it to sign your Android applications. The Android build process signs your application differently depending on which build mode you use to build your application. There are two build modes: debug mode and release mode . You use debug mode when you are developing and testing your application. You use release mode when you want to build a release version of your application that you can distribute directly to users or publish on an application marketplace such as Android Market. To sign your application manually, you need to perform the following steps: Compile your application in release signing mode. To do so in Eclipse, Save your file: ...