Certificate authorities
Just a few notes on certificate authorities...
Authorities. They are entities that are the authority on answering the question, is this server really who i think it is?
If I want to do some online banking I might go to bankofamerica.com. I definitely don't want to go to a malicious website that looks like Bank of America. I want to go to the actual Bank of America's website.
So let's say Bank of America hired me to build their website. I do all of the development and when I'm ready to publish it, I grab the bankofamerica.com domain name from godaddy or whatever registrar I use.
Part of registering a domain name is you get control of the DNS records for that domain.
So I add an A record that says bankofamerica.com -> 12.218.90.10, where 12.218.90.10 is the public IP address of my server.
After DNS propagation does it's thing (this can take some time), I go to bankofamerica.com and I can see my work.
What if someone registers bankofamerica.net and has it point to a malicious server? and someone accidentally goes to bankofamerica.net to do their online banking.
All browsers today have that little green lock icon that signifies the website you are visiting is valid. This is partly accomplished because of the certificate authority.