SSL/TLS Encryption
What is it?
SSL/TLS is the encryption protocol that puts the "S" in "HTTPS." It ensures that data traveling between a user's browser and a website is encrypted and can't be intercepted or tampered with. Cloudflare provides free SSL certificates to every customer and manages the entire encryption lifecycle.
What problem does it solve?
Without encryption, all data between a user and a website travels in plain text — meaning anyone on the network (ISPs, hackers on public Wi-Fi, governments) can read it. This includes passwords, credit card numbers, and personal information.
- Privacy: Users expect their browsing to be private. Google Chrome marks unencrypted sites as "Not Secure."
- Integrity: Without encryption, attackers can modify content in transit (man-in-the-middle attacks), injecting ads, malware, or fake content.
- Trust: SSL certificates verify that a website is who it claims to be, preventing impersonation.
- SEO: Google uses HTTPS as a ranking signal — encrypted sites rank higher in search results.
How does it work?
Cloudflare handles SSL/TLS at two points:
Edge Certificate (browser ↔ Cloudflare): When a user connects to a Cloudflare-protected site, they get an encrypted connection to the nearest Cloudflare data center. Cloudflare provides and manages this certificate automatically — customers don't need to buy or renew certificates.
Origin Certificate (Cloudflare ↔ origin server): The connection between Cloudflare and the customer's origin server can also be encrypted. Cloudflare offers free origin certificates for this purpose.
Encryption modes (from least to most secure):
- Off: No encryption (not recommended).
- Flexible: Encrypted between browser and Cloudflare, but unencrypted between Cloudflare and origin.
- Full: Encrypted end-to-end, but origin certificate isn't strictly validated.
- Full (Strict): Encrypted end-to-end with validated origin certificate (recommended).
Cloudflare also supports advanced features like TLS 1.3 (the latest and fastest version of the protocol), HSTS (HTTP Strict Transport Security), and Automatic HTTPS Rewrites.
Why it matters strategically
Universal SSL was a landmark Cloudflare initiative — in 2014, they gave free SSL to all customers, doubling the number of encrypted sites on the internet overnight. This cemented Cloudflare's reputation as a company that raises the baseline of internet security for everyone. It's also a key part of the "land" motion: free SSL brings customers in, and then they discover paid products.