Protocols | Computer for GCSE/IGCSE - Year 11 PDF Download

Introduction

Hypertext Transfer Protocol (HTTP) and Hypertext Transfer Protocol Secure (HTTPS) are essential for data exchange online. They ensure secure communication between users and servers.

Hypertext Transfer Protocol (HTTP)

• HTTP serves as the foundational protocol facilitating data exchange between a client and a server over the internet.
• It functions as a stateless protocol, implying that it does not retain information pertaining to past requests or responses.
• By default, HTTP operates through port 80 and transmits data in plain text, rendering it susceptible to interception and modification.

Hypertext Transfer Protocol Secure (HTTPS)

• HTTPS stands for Hypertext Transfer Protocol Secure, which serves as a secure iteration of HTTP. It employs encryption to safeguard information exchanged between a user's device and a website's server.
• By default, HTTPS functions on port 443 and utilizes either Transport Layer Security (TLS) or Secure Socket Layer (SSL) to encode data, ensuring enhanced security during transmission.
• Its primary objective is to guarantee the confidentiality and integrity of data being transmitted, thereby impeding unauthorized individuals from intercepting or tampering with the information.

SSL & TLS

• SSL, which stands for Secure Sockets Layer, was created by Netscape during the 1990s with the aim of facilitating secure communication on the internet.
• TLS, short for Transport Layer Security, succeeded SSL and is another security protocol designed to ensure secure communication over the internet.
• Both SSL and TLS employ a mix of symmetric and asymmetric encryption methods to safeguard data and guarantee its integrity.
• SSL functions at the transport layer of the OSI model, encrypting data before transmission across the network.
• The TLS protocol consists of two primary layers for enhanced security measures.

Handshake Layer

• This layer is crucial for establishing a secure connection between two endpoints.

Handshake Process

• Initiating a secure connection between two endpoints.
• Verification of the identity of each endpoint.
• Exchange of encryption methods and generation of a session key.

Record Layer

• The Record Layer is responsible for securely transmitting data between the client and the server.

Data Transmission Process

• The client/browser requests a secure connection to the server.
• The client/browser asks the server to provide its identity via a digital certificate.
• The server presents a digital certificate for validation by the client/browser.
• Upon validation, the client/browser signals the server to commence data transmission.
• An encryption method is agreed upon, and a session key is generated for secure data transfer.