With the expanding role of Google Cloud Storage in services and apps outside its own, the service has been updated for greater security in both the public and private enterprise arenas. This week Google Cloud Storage has been updated with 128-bit Advanced Encryption Standard, creating a unique key for each individual object's data and metadata. With this security update to Google Cloud, you'll have automatic encryption for all data before its written to disk.
This update is coming to the public this week at no charge to any user, be they a standard level Googler or one that pays massive amounts of cash for additional storage and support. This update is coming to users with no setup or configuration as it's modified on Google's side of the software and hardware equation.
NOTE: Google Cloud Storage is not the same service as Google Drive - one is made for projects, the other for files of all types.
Every bit of data within Cloud Storage with Google is both automatically and, as they say, "transparently" decrypted when an authorized user wishes to see it. This simply means that if you're logged in to your Google account, your files will be readable by you as they always have - it's only people trying to break in to your storage bin that'll be having a more difficult time seeing what they want.
The encryption involved in securing data for Google Cloud Storage is done so with per-object keys which are, in turn, encrypted with unique keys associated with the unique object owner. Google also leaves the option open for the user to encrypt their own data if they wish - they'll just have to encrypt it prior to uploading to Cloud Storage, of course.