My post title is clearly stating about my question . But lets repeat it. How can we stop google bots to crawl through a secure (not-willing-to-share) information from one of the website's directories.

Can we use robots.txt for this or you may suggest any other better treatment for this?

If Google crawls any secure information from a website content and shows it in seacrh engines then what can we do to let this information disappeared from Google search results?

Your co-operation is appreciated in adavance.