Can't get a network connection?
No problem, Google OS will still be able to check signatures
Google says Android will no longer require an internet connection to check whether applications are legit or potentially malicious.
From now on, the Play Store will embed metadata into apps' APKs that will be used to check whether or not the software is authentic, and confirm whether it came through the official Google souk or another Google-approved market.
Android will be able to verify that metadata – it's essentially cryptographic signatures – even when offline.
Signed legit apps that may not have been downloaded from the Play store, and may have been fetched from bandwidth-saving local peer-to-peer networks, will still be able to get updates and security fixes from the official store, once an outside connection is established, which is a nice side benefit Google is pitching to Android developers.