In Firefox 4 you no longer have the Status bar that showed the padlock in previous Firefox versions.
The padlock only shows that there is a secure connection and doesn't guarantee that you are connected to the right server.
So you might still be connected to the wrong server if you make a typo in the URL and someone has claimed that mistyped URL.
The functionality of the padlock has been replaced by the How do I tell if my connection to a website is secure? on the left end of the location bar.

See also:

• http://www.dria.org/wordpress/archives/2008/05/06/635/

How does a user know that the site is secure the site identity does not give that information. The padlock symbol was a simple quick check. Why was it not incorporated into the site identity where applicable. Sometimes I have gone onto a legitimate site and not completed a transaction as they were not using a secure connection.

You can click the How do I tell if my connection to a website is secure? on the left end of the location bar to see the padlock if there is a secure connection.
A click on the "More Information" button will show more details about the connection.
The background color of the "Site Identity Button" on the left end of the location bar will change color (blue or green) and show the domain in case of a secure HTTPS connection.

• Hover the How do I tell if my connection to a website is secure? then to see "Verified by xxxx"
• Click the "Site Identity Button" on the left end of the location bar to see the padlock
• Click the "More Information" button in that pop-up to see additional information about the connection.

You can use this extension to get a padlock on the location bar.

• Padlock: https://addons.mozilla.org/firefox/addon/padlock-icon/

Sorry, but you should not have to click anything to tell if the connection is encrypted. This is a problem for many people and will be a big issue. I understand that the site at the other end may or may not be legitimate and can understand the need to address that issue. However, removing the encryption icon is not the proper solution. I would suggest that the encryption icon be reinstated but add a identity icon as well and remove them from the URL bar and relocate them directly above the URL bar with a slightly larger size. Notice that in the image there is no way of telling if the connection is encrypted or secure.

This sounds very silly!! Removing the lock icon from bottom of FF is probably unnecessary anyway.

Sure, those of us that know how to check the address bar and look for https:// is all well and good but inexperienced users will have for many years known about the Lock icon on the bottom bar!

Now IMHO if you can show this after clicking a link on the address bar then surely you can use the same info held on the address bar to display the Padlock icon on the Status Bar...!?

Reading in more details I can see why they've removed the Padlock but perhaps a better way should have been implemented.

I assume why this has been done is to force users to check the actual security certificate! By removing the padlock it makes people more aware about security. https:// like has been said means a Secure connection, that's what the S stands for! But it doesn't have anything to do with a certificate as such.

E.g. I host a few websites. If someone (me) who can setup sites wants to register a website address that's very similar to a legitimate webiste e.g. https://support.mokilla.com then you could be fooled into thinking you're at the correct address because the fake website is using a secure certificate for it self!! So if your eyes have been fooled by the spelling and you see the Padlock on the Status bar you maybe end up trying to login to a fake website and hence giving away your User Name and Login details!! Yep it's that simple..! ish..

That's why I think FF have removed the Padlock! But why not just make the distinction between a Secure Server and a secure Certificate!! I'm sure it would catch on and most people would appreciate the added awareness of the security measure. And I bet others would follow the idea!

Future Firefox versions (6+) won't even show the protocol anymore in the location bar and you only see the domain highlighted and the rest of the URL is of a fainter color.
You can restore that via the pref browser.urlbar.formatting.enabled in Firefox 6+ versions.
You need to get used to checking the background color of the Site Identity Button showing the domain in case of a (verified) secure connection.

• https://support.mozilla.com/kb/Site+Identity+Button

Not sure about some of those changes until I see them but as long as users can easily change or have an option on install to keep the old style then all good!

I kept with FF 5 until today but I've had to give up on it for now. I've gone back to Ver 3.6.19 because Ver 5 hogs memory. The last straw was when returning to my PC it took me 15 mins to close it down as it took also every last byte :( just keeps hanging my PC, very bad indeed. When the memory hogging problem is fixed then I'll start using it but not before then! I do actually prefer Ver 5 now so this is annoying that's it's not working well for me, it's just not handling RAM properly. I also installed the add on so I could keep the Padlock etc. The colour system I agree now is a better system for security, but in future think about sticking in a pop-up perhaps saying what's changed as not all of us read the changes log! And this change was a big move away from what people have been use to for many years!