What is SSL Certificate?
SSL stands for Security Sockets Layer. It's a digital security system that enables encrypted communication between a server and a browser. SSL certificates allow websites to transform HTTP into HTTPS, which is more secure. An SSL certificate is a tiny data file that contains a cryptographic key to its details. It is called public-key cryptography.
This type of cryptography works through two keys. One is a private key, and another one is a public key. The public key is related to the server and accessible with the public domain. You can encrypt any message with the public key.
Suppose you are John. If you want to send a message to Jenny, you will have to lock it with Jenny's public key. And only Jenny's private key will able to decrypt it. Only Jenny has her private key, so she is the only one who can use this to unlock your message. If someone intercepts the message before Jenny unlocks it, all they will get is a cryptographic code. This is how SSL works between a server and a website.