what is certificate for in safari ?

[880]

I cant open FB since last week....
i know my sister did it becuz i dont study..
but i need it now!
i saw something called certificate information...
how to recover it?

[DunbarPappy®ϟϟ]

"Certificates" are digital identification devices used by websites to authenticate themselves to your browser, essentially saying that a Trusted Authority has verified that the website is who it says.
It is your browser that has a 'library' of known Trusted Certificate Authorities and what Certificates they have issued which is examined when you encounter a website with one of these Certificates, and it compares the two and if all's well, lets' the encrypted data exchanges between you and the site commence (indicated by 'https' address prefix).
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Updating the browser will often rectify any Certificate issues, but if you're getting a 'Certificate error' notice, your computers time might me off...even a little bit will cause troubles.
Most common fix:
Right click tray time> "Adjust..."> Update.
While here, tick 'Automatic synchronize...'