Reading the book is like being an eavesdropper as two companions take a long country walk.

ECONOMIST: Russia and the West

Now that there is one, the eavesdropper's days may be numbered.

ECONOMIST: Quantum information technology

Take one colleague who said that as a Welsh learner, or as she puts it, "a fluent eavesdropper" she found the Welsh-related questions "deeply unsatisfactory".

BBC: 2011: The Year of Sharp Decreases

The NSA is America's eavesdropper, the equivalent of GCHQ, and may well have picked up evidence about bin Laden's plans, but James Bamford says it did not have enough analysts who understood the culture of fundamentalism and failed to spot the clues.

BBC: President Bush

That does not matter for classical telecoms, but matters very much for quantum cryptography, which relies on the fact that no eavesdropper can intercept the message without changing those quantum states, and thus giving away the fact that he is on the line.

ECONOMIST: Quantum information technology

The information from the beam-splitter is then transmitted separately to the recipient, so that he knows whether to accept C unaltered as part of the message, or apply one of three mathematical transformations to it, to arrive at the right result (this does not compromise secrecy, since any eavesdropper will not know what the transformation needs to be applied to).

ECONOMIST: Quantum information technology