Yes you will be able to use the same sessions.
It does make a difference; https needs to do two trips as opposed to one for http. There are some sites that have chosen recently to use HTTPS exclusively - with computers, internet connections and browsers processing being quicker these days, it can be argued that you don’t need to use http; however I still only secure the pages that require secure data. I just think save the users some grief if the load becomes great.
You can go on google and search for generating a self-signed certificate. You can then configure the self-signed certificate in the same way that you will with your real cert. When you test you will get a warning that it is not using a secure certificate, but you can test all your content that is secured using https.
So yes it can be done, just a little work. I doesn’t hurt to know how to do this so it is time well spent.
i know i have to redirected the links for internal pages. but what about index page.
When the hosting provider will install the ssl certificate then if a user will type “domain.com” then the site will automatically get redirected to “https://domain.com” or it will still open at “domain.com”
because index.php loads automatically when the domain name is typed in address bar
This can be enforces a couple of different way.[/SIZE]
Use stealth redirection. You configure this via your Public DNS. Not all DNS hosts support this service. When users type http://, https:// or just your domain they will be redirected to https://your_domain.com
Use mod-rewrite configured on your server. If you are using Apache then this would be set in a .htaccess file and you would need to have the mod-rewrite module enable on the server your using; typically hosts have this enabled with shared hosting.