It is a possibility that in the near future that sites which use encryption could get a search engine rank boost. Do you think that this potential change is a way to encourage more use of SSL/TLS encryption on web pages?
@Glenn yes you are correct its for user as well as website security purpose, its employes at the sites that stores users information, so I would say if you have a site which is only providing the information then there's no need to install SSL.
Secure pages are more authentic than normal webpages so Google algorithm giving minor ranking advantage.But its not very strong factor to get huge advantage. So if a webpage contains high quality content then its equivalant to secured page.
https provide a better security for the website but i am not sure whether google would provide better ranking boost for this.There are a lof of high quality websites with "http" having better rankings than "https"