How to check an application's checksum or hash on Google Play? Some free applications on Google Play are limited to the United States so the rest of the world has to use dodgy sites to get them. However the security of such sites are questionable as the apps might be modified and contain some kind of malware.
Is there a way to get the SHA or MD5 hash of the apk file from the play store so it can be compared with the downloaded one to make sure that it's safe?
The  Guardian Project's free and open-source app Checkey does much of what you're looking to do.

via F-Droid:
"Checkey is a utility for getting information about the APKs that are installed on your device. Starting with a list of all of the apps that you have installed on your device, it will show you the APK signature with a single touch, and provides links to virustotal.com and androidobservatory.org to easily access the profiles of that APK. It will also let you export the signing certificate and generate ApkSignaturePin pin files for use with the TrustedIntents library."