What is SSL?

SSL (Secure Sockets Layer) is a cryptographic protocol originally developed by Netscape in the 1990s to provide secure communication over computer networks, particularly the internet. Although SSL has been superseded by TLS (Transport Layer Security), the term ‘SSL’ is still commonly used to refer to both SSL and TLS protocols, and SSL certificates are universally called ‘SSL certificates’ even when they actually use TLS.

SSL Protocol Versions and Security

SSL went through several versions before being replaced by TLS:

SSL 1.0: Never publicly released due to security flaws
SSL 2.0: Released in 1995, now deprecated due to vulnerabilities
SSL 3.0: Released in 1996, deprecated in 2015 due to POODLE attack
TLS 1.0+: Modern replacement protocols offering enhanced security

How SSL/TLS Works

SSL/TLS creates an encrypted tunnel between a client (like a web browser) and a server, ensuring that data transmitted between them cannot be intercepted or tampered with by third parties. The protocol uses a combination of asymmetric encryption for the initial handshake and symmetric encryption for data transfer, providing both security and performance efficiency.