By Sailee Shingare | M.S in Computer Science, Northern Illinois University
Every time you visit a website, your browser and the server have a conversation. That conversation happens over a protocol — either HTTP or HTTPS.
You’ve seen both in your browser’s address bar. But what’s actually different between them, and why does it matter?
Let’s break it down.
What is HTTP?
HTTP stands for HyperText Transfer Protocol. It’s the foundation of data communication on the web — the set of rules that defines how your browser requests information and how servers respond.
When you visit a website over HTTP, here’s what happens:
- You type a URL in your browser
- Your browser sends a request to the server
- The server sends back the webpage
- Your browser displays it
Simple. But there’s a problem — everything is sent in plain text. Anyone sitting between you and the server can read it. Your passwords, your credit card numbers, your messages — all visible.
This is where HTTPS comes in.
What is HTTPS?
HTTPS stands for HyperText Transfer Protocol Secure. It’s HTTP with an extra layer of security called TLS (Transport Layer Security) — previously known as SSL.
The S in HTTPS means everything between your browser and the server is encrypted. Even if someone intercepts the data, they see nothing but scrambled gibberish.
What Actually Happens When You Visit an HTTPS Website
When you visit an HTTPS site, your browser and the server perform a TLS Handshake before any data is exchanged. Here’s what happens step by step:
Step 1 — Client Hello Your browser says hello to the server and shares which encryption methods it supports.
Step 2 — Server Hello The server picks an encryption method and sends back its SSL certificate — a digital document that proves the server is who it claims to be.
Step 3 — Certificate Verification Your browser checks the certificate against a list of trusted authorities. If it’s valid, the connection proceeds. If not, you see a warning — “Your connection is not private.”
Step 4 — Key Exchange Your browser and the server agree on a secret key used to encrypt the session. This key is never sent over the internet — both sides calculate it independently.
Step 5 — Encrypted Communication Begins From this point on, everything is encrypted. Your data is safe.
This entire handshake happens in milliseconds — you never notice it.
Why Does Google Prefer HTTPS?
Since 2014, Google has used HTTPS as a ranking signal. Websites using HTTPS rank higher in search results than HTTP equivalents.
Additionally, since 2018, Google Chrome marks all HTTP sites as “Not Secure” in the address bar. This immediately reduces user trust and increases bounce rates.
If you run a website, HTTPS is no longer optional — it’s essential.
What is an SSL Certificate?
An SSL certificate is a digital document issued by a trusted Certificate Authority (CA) like Let’s Encrypt, DigiCert, or Comodo. It contains:
- The website’s domain name
- The certificate’s expiration date
- The public key used for encryption
- The CA’s digital signature
When your browser sees a valid certificate from a trusted CA, it displays the padlock icon. When the certificate is missing, expired, or from an untrusted source — you get a security warning.
Getting HTTPS for Free
You don’t need to pay for HTTPS anymore. Let’s Encrypt is a free, automated Certificate Authority trusted by all major browsers.
Most hosting providers — AWS, Azure, Cloudflare, Netlify — offer free SSL certificates with one-click setup. There’s no excuse for running an HTTP website in 2024.
The Bottom Line
- HTTP = fast but insecure, data sent in plain text
- HTTPS = secure, encrypted, trusted by browsers and Google
- The TLS handshake happens in milliseconds and protects everything you send
- Always look for the padlock before entering passwords or payment details
If you run a website, use HTTPS — it’s free and essential
Next time you see that padlock in your browser, you’ll know exactly what’s happening behind the scenes.