For centuries mathematicians have been wrestling with prime numbers. Those in the red corner have been searching for larger and larger primes, whilst those in the blue corner have been looking for ways of breaking numbers down into their prime factors. In this professional knowledge programme for maths teachers, we too wrestle with prime numbers and show how their use in cryptography algorithms helps to keep our money safe. Our presenter, Matthew Tosh, leads us on a journey that starts with Euclid's fundamental theorem of arithmetic and ends in the City of London, where we finally get to understand the role prime numbers play in internet security.

Video Series: Professional Knowledge
Release Date 2009