apktool b source.apk -f -o edited.apk
keytool -genkey -v -keystore class.keystore -alias alias_name -keyalg RSA -keysize 2048 -validity 10000
jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore class.keystore $APP alias_name
jarsigner -verify -verbose -certs my_application.apk