TLS notes
- key exchange between client and server
- data encryption
- handshake integrity
- certificates
When you come across "application keys" you know you are dealing with diffie helman eliptical curve technique.
Encryption protocols are also known as ciphers. AES is probably the most-used.
Beyond the encryption protocol, there is authentication and integrity checks whose purpose is to validate that the data was not tampered with in-transit.
A certificate authority is nothing more than a server that is running software that allows it to create certificates.
A CA creates a private key (basically a password) that's stored only on the server that's running the CA. That key will be combined with some mathematics that create a certificate.
A certificate is nothing more than a bunch of numbers stored in a document.
That certificate is called the root certificate, and it's used to generate other certificates.
Root certificates are typically installed in the OS or web browser. Google Chrome, for example, will keep a list of valid root certificates (e.g., semantic, rapidssl, verisign). These need to be updated every once in a while because they expire.
The whole purpose of a certificate is to authenticate that the server is who it says it is.