Mac: Google Drive is finally here, promising awesome Dropbox-like online storage and file syncing — but also the same security and privacy caveats that come with storing information on cloud servers. Macworld offers this handy file-encryption tool that works with Google Drive for drag-and-drop encrypting on your desktop.
It's an Automator action from Armin Beigel called "Create Disk Images From Files". Once you download the script and unpack the ZIP file, all you need to do is launch Automator on your Mac then import the action and drag it into the Automator workflow area. Select Google Drive as the folder in the options settings by browsing to the folder in Finder. To make this this a compressed file in Google Drive, click the checkboxes to compress the image and encrypt the image, then in the file menu, save the application to your desktop (I named it "Encrypt File to Google Drive").
Now every time you drag a file to that shortcut, you'll be prompted for a password and the file will be encrypted and saved to your Google Drive folder on Google. Neat, right?
Here's the Macworld article for more information and the download link.