Rupert Goodwins' Diary

Monday 10/5/2004Not a good day for secrets. A student in Dublin works out a way to extract the words that have been blanked out on those teasingly declassified documents issued by spooks and their friends.

Monday 10/5/2004
Not a good day for secrets.

A student in Dublin works out a way to extract the words that have been blanked out on those teasingly declassified documents issued by spooks and their friends. Seems that because word processors are so good at positioning text on the page with such precision, you can count the number of pixels in the missing word. You then identify the font and font size, and ask your friend the computer to find all the words that, if printed in that font at that size, would fill the space. You'll get a handful of words, and in the context of the passage it's child's play to pick the right one. She managed to work out that the South Koreans leaked some helicopter information to Iraq, for example, which probably makes her more successful by a factor of, oh, several million than most of the intelligence workers involved in the Mesopotamian adventure.

Then, an IBM research scientist reports today that by throwing the sound of someone typing into a neural network, he can detect which key is being pressed with around eighty percent accuracy. It has to be trained first, but that's not too hard, and it's good enough to work over a cellphone or other radio bugging device. In fact, he reckons that once it's trained for one keyboard, it'll work with others of the same make and model, and that with some more work he can reduce the training requirement considerably. It's all standard hardware and software, and you can probably do it for around 200 quid. The guy's name is peculiarly appropriate: Dmitri Asonov

Finally -- and this won't be a surprise to anyone who used to own a BBC Micro -- the tiny sounds computer components make when voltages change can be picked up and decoded to reveal a 'surprising amount' of information about what the computer is up to. This comes as something of a shock to the Israeli researchers who are trying this out, but anyone who has a Beeb in their nerdy past will be familiar with the soft, breathy crackling the machine used to make as it churned through its calculations. At the time, I just thought it was a charmingly eccentric side-effect of Acorn's peculiar design practices -- now I know it was part of the Global Conspiracy to report everything we did back to the secret powers that run the planet.

In my case, it involved writing software that played "The Teddy Bears Picnic" for a game that some friends were developing. It took quite a long time to get it right, during which period most of my family were driven to using ear-plugs, headphones and morphine to survive. I do hope the CIA didn't mind.