Source: http://www.engadget.com/2013/01/18/chrome-25-ssl-encrypted-search-everyone/
Chrome users with something to hide have heretofore been required to sign in to Google to keep their omnibox searches hidden from prying eyes -- but today's Chrome 25 beta update changes that. Now all searches are automatically encrypted, whether you're signed in or not. It's certainly not the first browser to implement such a security feature -- Firefox 14 switched to HTTPS for all searches last year -- but it's a welcome change all the same. With web voice recognition and security whitelists on the docket as well, the latest version of Chrome is setting up to be quite the must-have, especially for those who want to keep their Justin Bieber search results to themselves.
Source: Chromium Blog