How they have worked to undermine the technologies used by billions of people every day to protect everything from mundane messages — or webcam chats — to their most secret thoughts.One of the most significant technologies being targeted by the intelligence services is encryption.A black shrouded figure appears on the screen, looming over the rapt audience, talking about surveillance.
In practice, these government controls didn't make much difference to ordinary people, as there were few uses for code-making — that is, encryption — outside the military.
But all that changed with the arrival of the personal computer.
Governments fought to control the use of encryption, while privacy advocates insisted its use was essential — not just for individual freedom, but also to protect the commercial development of the nascent internet.
What followed was a series of skirmishes, as the US government and others made increasingly desperate — and unsuccessful — efforts to reassert control over encryption technologies.
Online, encryption surrounds us, binds us, identifies us.
It protects things like our credit card transactions and medical records, encoding them so that — unless you have the key — the data appears to be meaningless nonsense.
Few experts even knew that the option to use the weaker encryption still existed in the browsers commonly used today — a good example of the dangerous and unexpected consequences of attempts to control privacy technologies, long after the political decisions affecting it had been reversed and forgotten.
But by the early 2000s, it appeared that the privacy advocates had effectively won the crypto wars.
It became an even bigger issue as the huge economic potential of the web became apparent.
"The internet and the protocol it's all based on was never intended to be secure, so if we are going to rely on the internet as part of our critical national [and] international infrastructure, which we do, you've got to be able to secure it, and the only way to do that is to layer encryption over the top," explains Professor Alan Woodward, a computer security expert at the University of Surrey.
Under the scheme, the US government would agree to license encryption providers, if they gave the state access to the keys used to decode communications.