SSL (Secure Sockets Layer) and TLS (Transport Layer Security) are both cryptographic protocols that encrypt internet connections. The practical difference: all SSL versions are deprecated and insecure. TLS is what actually secures the web today. When people say “SSL certificate,” they mean a certificate used with TLS.
If you’re here because you’re wondering whether you need to do something — jump to what you need to do.
Quick comparison
| SSL | TLS | |
|---|---|---|
| Full name | Secure Sockets Layer | Transport Layer Security |
| Created by | Netscape (1994) | IETF (1999) |
| Latest version | SSL 3.0 (1996) | TLS 1.3 (2018) |
| Status | ⛔ All versions deprecated | ✅ TLS 1.2 and 1.3 in active use |
| Known vulnerabilities | POODLE, BEAST, CRIME, DROWN | None (TLS 1.3), few mitigable (TLS 1.2) |
| Performance | Slower (2+ round trips) | TLS 1.3: 1-RTT handshake |
| Forward secrecy | Optional (rarely used) | Mandatory in TLS 1.3 |
| Cipher suites | Weak (RC4, DES, export ciphers) | Strong (AES-GCM, ChaCha20) |
| Message auth | MAC with MD5/SHA-1 | HMAC with SHA-256+ |
| Browser support | Removed from all browsers | Universal |
The complete version history
| Year | Protocol | What happened |
|---|---|---|
| 1994 | SSL 1.0 | Designed by Netscape. Never released — serious flaws found internally before launch. |
| 1995 | SSL 2.0 | First public release. Used by early HTTPS sites. Quickly found to have major vulnerabilities (weak MAC, susceptible to truncation attacks). |
| 1996 | SSL 3.0 | Complete redesign by Paul Kocher + Netscape. Widely deployed for 18 years. Broken by POODLE attack (October 2014). Deprecated by IETF in June 2015 (RFC 7568). |
| 1999 | TLS 1.0 | IETF standardized protocol based on SSL 3.0. Minor improvements. Vulnerable to BEAST attack (2011). Deprecated in March 2021 (RFC 8996). |
| 2006 | TLS 1.1 | Fixed BEAST vulnerability. Added explicit IV for CBC ciphers. Deprecated in March 2021 alongside TLS 1.0. |
| 2008 | TLS 1.2 | Major upgrade. Added AEAD ciphers (AES-GCM), removed MD5/SHA-1 from handshake, added signature algorithm negotiation. Still widely used and secure when configured correctly. |
| 2018 | TLS 1.3 | Current standard (RFC 8446). Removed all legacy algorithms, 1-RTT handshake, forward secrecy mandatory, encrypted handshake. Represents a fundamental redesign. |
Key moments:
- October 2014: Google discovers POODLE vulnerability — SSL 3.0 can’t be fixed, must be abandoned
- June 2015: IETF officially deprecates SSL 3.0 (RFC 7568)
- March 2021: IETF deprecates TLS 1.0 and 1.1 (RFC 8996)
- 2020-2021: All major browsers drop support for TLS 1.0/1.1
Why we still say “SSL”
The term “SSL” stuck because it came first. Netscape coined it in 1994, and by the time TLS replaced it in 1999, “SSL” was already common vocabulary. Today:
- “SSL certificate” = a certificate used with TLS (not SSL)
- “SSL/TLS” = a hedge covering both terms
- “SSL” in product names = marketing, not the actual protocol
- “Free SSL” = a free TLS certificate
GetHTTPS, Certbot, Let’s Encrypt, ZeroSSL — all of them issue certificates for TLS connections, even when their names or marketing says “SSL.” The certificates themselves are X.509 format and work with any TLS version.
This article uses “SSL certificate” the same way the industry does: to mean a certificate used with TLS.
Technical differences that matter
Cipher suites
SSL relied on algorithms we now know are broken:
| Algorithm | Used in | Status |
|---|---|---|
| RC4 | SSL 2.0, 3.0 | Broken — RFC 7465 prohibits it |
| DES, 3DES | SSL 2.0, 3.0 | Broken/deprecated |
| MD5 | SSL handshake | Collision attacks demonstrated |
| Export ciphers | SSL (US policy) | Intentionally weak (40/56-bit keys) |
| AES-GCM | TLS 1.2, 1.3 | ✅ Current standard |
| ChaCha20-Poly1305 | TLS 1.2, 1.3 | ✅ Excellent for mobile/ARM |
TLS 1.3 reduces the cipher suite list to just 5 options — all secure. TLS 1.2 has 37+, some of which are weak. TLS 1.3’s simplicity means less room for misconfiguration.
Handshake speed
| SSL 3.0 | TLS 1.2 | TLS 1.3 | |
|---|---|---|---|
| Full handshake | 2+ round trips | 2 round trips | 1 round trip |
| Resumed session | 1 round trip | 1 round trip | 0-RTT (data with first message) |
| Practical latency | 60-120ms | 40-80ms | 20-40ms |
TLS 1.3’s 0-RTT resumption means returning visitors can send encrypted data immediately — no handshake delay at all.
Forward secrecy
Forward secrecy means every connection uses a unique key. Even if someone steals the server’s private key, they can’t decrypt past conversations.
- SSL 3.0: Didn’t support forward secrecy
- TLS 1.0-1.2: Supports it (via ECDHE) but also allows RSA key exchange (no forward secrecy)
- TLS 1.3: Mandatory — RSA key exchange removed entirely
Message authentication
- SSL: Used MAC with MD5 or SHA-1 — both now considered weak
- TLS: Uses HMAC with SHA-256 or stronger — no known weaknesses
What you need to do
For most website operators: probably nothing. If you:
- Have a valid SSL/TLS certificate (from Let’s Encrypt or any CA)
- Use a reasonably modern web server (Nginx 1.13+, Apache 2.4.37+, IIS 10)
- Haven’t explicitly disabled TLS 1.2/1.3 in your config
…then you’re already using TLS. Your “SSL certificate” works with TLS 1.2 and 1.3 automatically — the same .pem files serve both protocols.
One thing to verify: Make sure TLS 1.0 and 1.1 are disabled on your server. They’ve been deprecated since 2021.
Nginx:
ssl_protocols TLSv1.2 TLSv1.3;Apache:
SSLProtocol all -SSLv3 -TLSv1 -TLSv1.1How to check your current TLS version:
# Shows which TLS version is negotiated
echo | openssl s_client -connect yourdomain.com:443 -servername yourdomain.com 2>/dev/null | grep "Protocol"
# Expected: TLSv1.2 or TLSv1.3Online tool: SSL Labs Server Test shows exactly which protocols your server supports.
TLS 1.3 adoption
As of early 2026, 62% of websites support TLS 1.3. All major browsers support it. If your server is up to date, you likely have TLS 1.3 already.
Servers that support TLS 1.3 out of the box (no special config needed):
- Nginx 1.13+ (with OpenSSL 1.1.1+)
- Apache 2.4.37+ (with OpenSSL 1.1.1+)
- Caddy (all versions — always uses the latest TLS)
- Cloudflare (automatic)
- AWS ALB/CloudFront (automatic)
What’s ahead: post-quantum cryptography
The next major TLS development is post-quantum key exchange — protecting against future quantum computers that could break current key exchange algorithms (ECDHE, RSA). Google Chrome and Cloudflare have already started experimenting with hybrid key exchange (classical + post-quantum) in TLS 1.3.
This won’t require new certificates — the change is in the key exchange mechanism, not the certificate format. Your Let’s Encrypt certificate will work with post-quantum TLS when it arrives.
Frequently asked questions
Do I need a different certificate for TLS vs SSL?
No. The same certificate works with any TLS version. “SSL certificate” and “TLS certificate” refer to the same X.509 file. When you get a certificate from GetHTTPS, it works with TLS 1.2 and 1.3 — no special configuration.
Is TLS 1.2 still secure?
Yes. TLS 1.2 with AEAD cipher suites (AES-GCM or ChaCha20-Poly1305) is secure for production use. TLS 1.3 is better (faster, simpler, enforces forward secrecy), but TLS 1.2 remains safe. The recommended config is TLSv1.2 TLSv1.3.
Should I force TLS 1.3 only?
Not yet. About 38% of sites don’t support TLS 1.3, and some older clients (corporate environments, embedded devices, Java 8) may only support TLS 1.2. Dropping TLS 1.2 today would lock out some legitimate users. Support both.
Will “SSL certificates” stop working?
No. Despite the name, “SSL certificates” are X.509 certificates that work with any TLS version. The name is a legacy artifact. Your certificates will continue working as long as the CA is trusted and the certificate hasn’t expired.
Is HTTPS the same as SSL or TLS?
HTTPS is HTTP + TLS. It’s the result of applying TLS encryption to HTTP connections. When you visit https://example.com, your browser uses the TLS protocol to encrypt the HTTP traffic. HTTPS isn’t a separate protocol from TLS — it’s HTTP running inside a TLS tunnel.
What is the POODLE attack?
POODLE (Padding Oracle On Downgraded Legacy Encryption) was discovered by Google in October 2014. It exploited a flaw in SSL 3.0’s CBC cipher padding. The attack allowed an attacker on the same network to decrypt individual bytes of encrypted traffic. Because the flaw was in the protocol design (not a specific implementation), SSL 3.0 couldn’t be patched — it had to be abandoned entirely. This was the final nail in SSL’s coffin.