Imagine the Internet is like sending letters between two friends. HTTP is the language or format the letter is written in, like using English or another language. TLS is the envelope and lock you use to protect the letter so no one else can read it. Different versions of HTTP or TLS are like using newer types of letters or stronger locks to keep things safe.

The correlation between TLS (Transport Layer Security) versions and HTTP (Hypertext Transfer Protocol) versions revolves around securing communication between clients (like web browsers) and servers (like websites). While HTTP defines how data is structured and transferred, TLS provides the encryption layer that secures that data in transit.

Although TLS and HTTP are separate protocols with distinct functions, they often work together. Below is a breakdown of their relationship through different versions.

HTTP Versions

  1. HTTP/1.1:    - Introduced in 1997.    - Uses a text-based request-response model (e.g., GET and POST methods).    - Works with both non-secure (HTTP) and secure (HTTPS) protocols. HTTPS in HTTP/1.1 is enabled by adding TLS encryption on top of it (via a handshake before the HTTP data is transferred).    - Can use multiple versions of TLS (e.g., TLS 1.0, 1.1, 1.2, and 1.3).

  2. HTTP/2:    - Introduced in 2015.    - Binary-based, instead of text-based, which makes it more efficient.    - Designed to support multiplexing (sending multiple requests at once over a single connection), header compression, and server push.    - Often used exclusively over TLS, and many browsers require HTTP/2 to be used with TLS 1.2 or higher. It improves performance but relies heavily on encryption.

  3. HTTP/3:    - Built on top of QUIC (a transport layer protocol that integrates security natively).    - Uses TLS 1.3 exclusively as its encryption mechanism, but it handles the TLS handshake within QUIC, not separately as in earlier versions.

TLS Versions

  1. TLS 1.0 (deprecated):    - Released in 1999. It had several vulnerabilities, which led to its deprecation.    - Compatible with HTTP/1.1, but generally not recommended anymore.

  2. TLS 1.1 (deprecated):    - Released in 2006. Like TLS 1.0, it is now deprecated due to security flaws.

  3. TLS 1.2:    - Released in 2008. Still widely used and supported by most browsers and services.    - Compatible with both HTTP/1.1 and HTTP/2.    - Provides strong encryption and more robust security mechanisms compared to its predecessors.

  4. TLS 1.3:    - Released in 2018. It simplifies the handshake process and enhances security and performance.    - Compatible with HTTP/1.1, HTTP/2, and HTTP/3.    - HTTP/3, built on QUIC, requires TLS 1.3 due to its more efficient handshake and stronger security features.

Correlation Between TLS and HTTP Versions

  • HTTP/1.1 can work with older and newer versions of TLS, though it’s common to use TLS 1.2 or TLS 1.3 for security reasons today.
  • HTTP/2 is typically used with TLS 1.2 or higher. Many browsers require HTTP/2 over TLS for security, making TLS a near-mandatory part of the protocol.
  • HTTP/3 is designed to work specifically with TLS 1.3 because of the integration of QUIC, which natively handles secure transport.

Summary of Correlations:

HTTP Version TLS Version Compatibility     
HTTP/1.1         TLS 1.0, 1.1, 1.2, 1.3 (modern sites use 1.2 or 1.3)
HTTP/2           TLS 1.2, TLS 1.3 (1.2 is most common)
HTTP/3           TLS 1.3 only                 

Example of Big Companies Using These Protocols

  • Google: One of the first to deploy HTTP/2 and HTTP/3 with TLS 1.3 in their web services like Gmail and YouTube. Google’s QUIC project eventually became the foundation for HTTP/3.
  • Cloudflare: Also an early adopter of HTTP/3 and TLS 1.3, enabling faster and more secure browsing across its CDN services.

References