Mystery of SSL - Part 2 - What is SSL?

Recap:
     In the previous post, we understood that sending secret in clear text is not secure, through an example of passing notes between friends, to check out Part 1 what is encryption?.

What is SSL?

Nowadays we make most of our purchases online, we always ask a question is my debit card number is secure? To answer this question, we have to ask ourselves the following questions,

1. Do I trust the shopping website?
2. Do I trust the payment gateway (where we enter debit card number)?

Trusting websites is just one part of the issue, another issue is that our debit card can be readable by any intermediate devices (routers, switches, etc.) during transit, this is possible if it is sent in an insecure channel. 

So how can we ensure that our secrets (passwords, phone number, and payment information) are not leaked? Here comes SSL for rescue.

SSL (Secure Socket Layer) is a way to send your debit card number to your bank in a secure channel. If you still have a question that what is a secure channel, it nothing but encryption between you and the bank. 

You could ask me how can I identify in the browser that my communication channel is secure?

The following illustration shows how to differentiate between a secure website vs an insecure website.

A website which is secure

Insecure website

How does my browser know it is a secure website?

You have to click on the lock icon or `Not Secure` to understand how it does. The following images explains difference between secure and insecure website. The content displayed in the window varies from browser to browser.

Secure website

Insecure website

In the secure website, the first line you will see is that you can trust this website to provide your sensitive information.

In the next line, I have marked something called a certificate. You can ask what is a certificate, wait for the next part to know about it. 

If you have any questions related to SSL topic, let me know in the comments.