Overview

SSL and TLS are cryptographic protocols that secure data in transit between clients and servers, but SSL is the deprecated predecessor while TLS is its actively maintained successor. Every SSL version is now broken or prohibited, yet the term “SSL” persists in everyday usage even though modern connections actually negotiate TLS.

Comparison Diagram

SSLTLSSSL 2.0 (1995)broken by DROWNSSL 3.0 (1996)broken by POODLEall versions prohibitedTLS 1.0 (1999)TLS 1.1 (2006)TLS 1.2 (2008)widely deployedTLS 1.3 (2018)current standardtime →deprecated / prohibitedactively maintained

Comparison Table

AspectSSLTLS
OriginDeveloped by Netscape starting in 1995Standardized by the IETF in 1999 as SSL’s successor
Versions releasedSSL 2.0, SSL 3.0 (SSL 1.0 never shipped)TLS 1.0, 1.1, 1.2, 1.3
Handshake processFull handshake only, with weaker key exchange optionsStreamlined handshake; TLS 1.3 cuts a round trip and defaults to forward secrecy
Cipher suite supportPermits weak ciphers like RC4, DES, and export-grade cryptoMandates modern AEAD ciphers (AES-GCM, ChaCha20-Poly1305); weak ciphers dropped entirely in 1.3
Known vulnerabilitiesPOODLE broke SSL 3.0; DROWN broke SSL 2.0BEAST and CRIME hit early TLS 1.0 but were patched in later versions
Current statusAll versions formally deprecated and prohibited (RFC 7568)TLS 1.2 and 1.3 are the current standards; 1.0/1.1 also deprecated
Everyday terminology“SSL certificate” and “SSL/TLS” persist as colloquial shorthandThe protocol actually negotiated by nearly every modern HTTPS connection

Key Differences

  • SSL is the obsolete predecessor; TLS is the actively maintained successor protocol
  • TLS 1.3’s handshake trims a round trip compared to SSL’s full handshake
  • SSL still permits weak ciphers like RC4; TLS mandates modern AEAD ciphers
  • The label “SSL certificate” survives in marketing even though browsers negotiate TLS
  • SSL 3.0 was broken by POODLE, forcing its complete deprecation

When to Use Each

SSL

  • Legacy system interop: Only relevant when forced to talk to decades-old hardware or software that can’t negotiate anything newer, and even then it should be upgraded rather than relied on.
  • Protocol history research: Understanding SSL’s design and failures explains why TLS made the specific security choices it did.

TLS

  • Securing modern web traffic: TLS 1.2/1.3 is the baseline expectation for any HTTPS endpoint today.
  • API and service-to-service encryption: TLS’s AEAD ciphers and forward secrecy protect internal and external API calls from interception.
  • Meeting compliance mandates: Standards like PCI-DSS explicitly require TLS 1.2 or higher and prohibit SSL outright.