With the exclusion of the bottom toolbar in Firefox 4, the security padlock icon no longer shows. To verify if a site is secure, look in the address bar at the top of the page. If the beginning of the website starts with https:// (as opposed to http://) and the website's icon and company name show on a green or blue background (consult the attached image), then the website is secure.

For more details see https://support.mozilla.com/kb/Site+Identity+Button

Thank you so much for your informative, quick response. It really helped me to understand Firefox 4, more.

o))

Thank you for your quick reply. I have bookmarked the page for further reference.

 :o))