Key Exchange

This clip from the 2008 Royal Institution Christmas Lectures shows a simple demonstration of how two people can agree on a secret key, even though all of their communications are carried out in public. In the electronic world, secret key exchange allows computers to communicate securely, and is used, for example, when you give your credit card information to an on-line shop. You can watch the 2008 Royal Institution Christmas Lectures in full at: http://research.microsoft.com/~cmbishop or by visiting the Royal Institution web site. There is a dedicated web site to accompany the 2008 Christmas Lectures, with ten interactive games as well as downloadable PDF instructions for experiments which can be conducted at home or at school: http://www.rigb.org/christmaslectures08