Symmetric vs Asymmetric Encryption

Symmetric encryption: Symmetric encryption uses a single key to encrypt the message that is transmitted between client and server. The key is transmitted from one node to the other so that the other node can decrypt the data using the key.

Asymmetric encryption: Uses a public key that is transmitted in raw form to encrypt the second key which is used to encrypt the data that is sent. On the other hand, the receiver decrypts the private key using the known public key and then decrypts the data via using the private key.

Asymmetric encryption in digital certificates: The public key is transmitted between computers over a digital certificate. The certificate contains information about the organization and the public key.

Certificate authority: Their job is to issue and validate the certificate being used is accurate and indeed belongs to the organization that is using it.  

TLS: TLS is an encryption protocol designed to support asymmetric encryption when communicating data between client and server.

References:

https://www.cloudflare.com/learning/ssl/what-is-asymmetric-encryption/

https://www.cloudflare.com/learning/ssl/what-happens-in-a-tls-handshake/