As opposed to HTTP URLs which begin with "http://" and use port 80 by default, HTTPS URLs begin with "https://" and use port 443 by default.

HTTP is insecure and is subject to eavesdropping attacks which, if critical information like credit card details and account logins is transmitted and picked up, can let attackers gain access to online accounts and sensitive information. Ensuring data is either sent or posted through the browser using HTTPS, such information is encrypted and is secure.

In practice how is SSL used in today?s modern e-commerce enabled / online workflow and service society?

• To secure online credit card transactions.
  
  
• To secure online system logins, sensitive information transmitted via web forms, or protected areas of websites.
  
  
• To secure webmail and applications like Outlook Web Access, Exchange and Office Communications Server.
  
  
• To secure workflow and virtualization applications like Citrix Delivery Platforms or cloud based computing platforms.
  
  
• To secure the connection between an email client such as Microsoft Outlook and an email server such as Microsoft Exchange
  
  
• To secure the transfer of files over https and FTP(s) services such as website owners updating new pages to their websites or transferring large files.
  
  
• To secure hosting control panel logins and activity like Parallels, cPanel, and others.
  
  
• To secure intranet based traffic such as internal networks, file sharing, extranets, and database connections.
  
  
• To secure network logins and other network traffic with SSL VPNs such as VPN Access Servers or applications like the Citrix Access Gateway.

All these applications have a number of shared themes:

• The data being transmitted over the Internet or network needs confidentiality. In other words, people do not want their credit card number, account login, passwords or personal information to be exposed over the Internet.
  
  
• The data needs to remain integral, which means that once credit card details and the amount to be charged to the credit card have been sent, a hacker sitting in the middle cannot change the amount to be charged and where the funds should go.
  
  
• Your organization needs to assure your customers / extranet users that you are who you really say you are and not someone masquerading as you.
  
  
• Your organization needs to comply to regional, national or International regulations on data privacy, security and integrity.