BBC Security Correspondent Gordon Corera explores the history of the war between government and geeks to control computer cryptography.

The revelations from Edward Snowden that British and American spies have been working to break encryption have generated fierce debate. Privacy advocates argue that the spy agencies have undermined the whole internet by weakening the security on which we rely to keep our communications and transactions secure. At issue is whether people should be able to encrypt their messages so that they are entirely private – meaning also that the government won’t be able to read anything. But this latest fight is just the latest chapter in a battle going back decades.

In the 1970s, a group of quirky academics and scientists came up with a means of providing encryption to the masses. America’s National Security Agency went to war with them – doing its best to suppress the emerging technology of public encryption. In the 1990s the US government pushed to have every computer and phone installed with something called a ‘clipper’ chip which would allow the government to break encryption if needed – effectively a back door for the state. They lost that battle and so what we have learnt from the Snowden leaks is how they tried to work round encryption by hacking into companies and other spy-type methods to retain their edge.

Who will win the next round?

(Photo: A computer screen with a target, Credit: Mahmud Hams/AFP/Getty Images)