How-to Password Protect a Google Drive Spreadsheet?: Office tools moved from Desktop to Online. Google Drive features are awesome when compared to alternative services. It is very easy to protect a document on Desktop but when it comes to online office tools it is very easy by using a simple script.
Normal setup is as usual. For each new document, run the script once to give it the permissions it needs at which point you can encrypt or decrypt your data at will. First you need to setup a password when you first time encrypt a spreadsheet. In this process encryption is not automatic, you have to lock the document before you close. Detailed instructions link is given below.
How to Password Protect a Document in Google Drive.