TLS & SSL Explained: What Makes HTTPS Strong

In short: "SSL" is the old name; everyone now uses TLS. A strong setup means offering only TLS 1.2 and 1.3, modern ciphers with forward secrecy, a valid certificate with a strong key and signature, and no known protocol vulnerabilities. CyberScore's Deep TLS tab grades all of this the way SSL Labs does.

SSL vs TLS — what's the difference?

They are the same idea at different ages. SSL (Secure Sockets Layer) was the original protocol from the 1990s; it was replaced by TLS (Transport Layer Security), and every version of SSL is now considered broken and disabled. People still say "SSL certificate" out of habit, but the protocol doing the work today is TLS — specifically TLS 1.2 (2008) and TLS 1.3 (2018).

What happens during a handshake

When a browser connects over HTTPS, it and your server perform a short negotiation before any page data is sent. They agree on a protocol version, pick a cipher suite, the server presents its certificate to prove its identity, and the two sides derive the secret keys used to encrypt the rest of the session. Every one of those steps is a place where a weak choice can quietly lower your security — which is exactly what a TLS assessment inspects.

Protocol versions: new in, old out

Offer TLS 1.2 and 1.3 only. Disable SSL 2.0, SSL 3.0, TLS 1.0 and TLS 1.1 — all are deprecated and carry known weaknesses, and the PCI and browser ecosystems have already dropped them. TLS 1.3 is faster and removes many of the foot-guns of earlier versions, so enable it wherever your stack supports it.

Cipher suites & forward secrecy

A cipher suite is the specific combination of algorithms used for key exchange, encryption and integrity. The key property to look for is forward secrecy (sometimes "perfect forward secrecy"): it uses short-lived keys via ECDHE so that even if your server's private key is stolen later, past recorded traffic cannot be decrypted. Prefer ECDHE suites with AES-GCM or ChaCha20-Poly1305, and drop legacy ciphers like RC4, 3DES and anything using plain RSA key exchange.

An easy way to get a modern, safe cipher list is the Mozilla SSL Configuration Generator — pick "Intermediate" for broad compatibility or "Modern" for TLS 1.3-only clients.

The certificate

Your certificate proves you control the domain. For a strong grade it should:

Be valid and in date, from a trusted certificate authority (Let's Encrypt is free and fine).
Use a strong key — RSA 2048-bit or larger, or an ECDSA P-256 key.
Be signed with SHA-256 or better (never SHA-1).
Cover the right names (apex and www, or a wildcard) in its Subject Alternative Names.
Present the full chain so every client can verify it without extra downloads.

Automate renewal (for example with certbot or your host's built-in ACME) so a certificate never silently expires.

Known vulnerabilities to avoid

A good assessment also checks that your server is not exposed to classic protocol flaws — Heartbleed, ROBOT, insecure renegotiation, the CCS-injection bug and CRIME (TLS compression). Keeping OpenSSL and your server software patched clears almost all of these; CyberScore's Deep TLS tab flags any that remain.

Finish the picture with HSTS

Strong TLS gets undermined if a browser can still be tricked into a first plain-HTTP request. Adding the HSTS header forces HTTPS from the very first visit — see our security headers guide for the exact value.

Common mistakes

Leaving TLS 1.0/1.1 enabled "for old clients" long after they matter.
A certificate that is valid but served without its intermediate chain.
Non-forward-secret ciphers still in the list.
Letting a certificate expire because auto-renewal silently failed.

Grade your TLS setup

Open CyberScore, switch to the Deep TLS tab and enter your domain. You'll get an A+→F grade with the protocols offered, forward-secrecy status, certificate details and any vulnerabilities — a fast, SSL-Labs-style read on your HTTPS.

Run a Deep TLS scan →