What is the lock near the url?

[Magnetto]

What is it? I always noticed that the lock is either green or gray, as for example on this forum, and sometimes it is completely crossed out. What does this mean? Is it related to security?

[CrazyReaper]

I do not even know. I'd like to know now, too.

[Scinetic]

This sign indicates the encryption level. For example, if the lock is green, then the site has good encryption. If you see a crossed-out lock, then this site is not secure. To get this green lock, the owner must buy cheap ssl certificates.