Your Internet fingerprint is made up of loads of individually seemingly harmless items – but all put together point you out of a crowd!

  • Internet Protocol (IP) address – [article] – an internationally recognisable number, everyone has one you and the sites you access
  • Browser ‘user-agent’ – [pdf1] – this is the browsers identification available to any site you access through that browser
  • Browser plugins – [pdf1]  – different people use different plugins, your particular selection can help to identify you and possibly the plugins themselves could be revealing information to certain sites
  • Clock skew – [article] – sounds odd but how much your computers time is out (even if its milliseconds) is another way – when added with others – to uniquely point you out
  • Tracking cookies – [pdf2] – up to 4kbit of data stored on your computer
  • Flash cookies – [article] – up to 100kbit of data stored on your computer and can even be used to regenerate browser cookies after you have deleted them
  • and more…
  • Time Zone; Screen Size; System Fonts; …


  1. browser-uniqueness.pdf – EFF – Peter Eckersley
  2. iSEC_Cleaning_Up_After_Cookies.pdf – iSEC Partners – Katherine McKinley