Difference between HTTPS and SSL

bayCoder picture bayCoder · May 23, 2011 · Viewed 66.4k times · Source

What is the difference between HTTPS and SSL? I read about them and found following:

  • HTTPS: HTTPS is a combination of HTTP with SSL/TLS. It means that HTTPS is basically HTTP connection which is delivering the data secured using SSL/TLS.

  • SSL: SSL is a secure protocol that works on the top of HTTP to provide security. That means SSL encrypted data will be routed using protocols like HTTP for communication.

I am wondering where is the difference between these two? Or both are identical?

Answer

Anders Lindahl picture Anders Lindahl · May 23, 2011

The explanation of SSL that you've found is wrong.

SSL (Secure Socket Layer) or TLS (Transport Layer Security) works on top of the transport layer, in your examples TCP. TLS can be used for more or less any protocol, HTTPS is just one common instance of it.

HTTP is an application layer protocol.

In regular, non-encrypted HTTP, the protocol stack can look like this:

When using HTTPS, the stack looks like this:

  • HTTP
  • TLS (SSL)
  • TCP
  • IP
  • Ethernet