Episode 4 - Untangling The Web
The impact of computers increased dramatically when they were connected together to form the internet. But how does information make its way across the internet, through hundreds of computers to the right destination? How does a search engine find the web page you want amongst billions of possibilities in a fraction of a second? What will the web be like in years to come? And is your credit card number safe when you send it over the internet? In this lecture Chris Bishop will untangle some of the mysteries of the web. He will reveal one of the most surprising results in computer science, and will show how it is used to make web pages secure. We will discover ways of scrambling information to stop eavesdroppers from reading it, and we will see how quantum physics can provide us with a totally secret way to transmit data over the internet.

Episode 1 - Breaking The Speed Barrier How is it possible to build a machine as complex as the microprocessor with a billion tiny components packed into a space the size of a postage stamp?

Episode 2 - Chips With Everything Every day we interact with dozens if not hundreds of computers, often without even realising it. This lecture reveals the state-of-the-art in computer interaction.

Episode 3 - The Ghost In The Machine What is software, and how is it stored inside the computer? Why are some problems just too hard for any computer to solve, and how can we turn this to our advantage?

Episode 4 - Untangling The Web How does information make its way across the internet, through hundreds of computers to the right destination? How does a search engine find the web page you want amongst billions of possibilities in a fraction of a second?

Episode 5 - Digital Intelligence Computers are extraordinary machines, able to perform feats of arithmetic that far exceed the capabilities of any human. So why is a 3 year old toddler better at recognising everyday objects than the world's most powerful supercomputer?

Credits
for Five