As the whistleblower Edward Snowden leaks ever more information about global bugging operations — today it’s the US spying on the European Union, but a week or two ago it was the British government spying on participants in the last G8 summit — the question inevitably arises: how can you communicate securely in the modern world? And with that, the inevitable but somewhat horrifying answer — they are all going to have to start sending letters again. I hope the CIA has hung on to a kettle that it can use to steam them open.