Checks if an application is pristine (untampered) and from the official Mac App Store.
For technical details, see the blog post; "Are you from the Mac App Store?"
Code inspired by: RVNReceiptValidation
$ /fromAppStore /Applications/1Password.app checking if 1Password.app is from the OS X App Store app is signed with an Apple Dev. ID found receipt at: /Applications/1Password.app/Contents/_MASReceipt/receipt check 1 passed: bundle ID's match check 2 passed: app versions match check 3 passed: hashes match verfied app's receipt; it's from the OS X App Store!