Word Blotto

Working at CoreStreet, I’ve developed a nose for simple and elegant cryptography, and a recent project by Claire Whelan and David Naccache of Dublin City University smells mmm, mmm clever.  The researchers subjected declassified government documents with sensitive words blotted out to an obvious-in-retrospect process:

The first task is to identify the font, and font size the missing word was written in. Once that is done, the dictionary search begins for words that fit the space, plus or minus three pixels, Naccache explained.

After that, a bit of common-sense human intervention was sufficient to deduce the hidden words.

This is going to cause a lot of heartburn in the intelligence community.  There are staggering quantities of word-blotted documents crammed into government archives and the “Dublin Technique” puts many of them at risk.  I would be a bit surprised if word-blotting ever stood up to the type of serious cryptographic, linguistic and contextual analysis that important US documents are subjected to by rival governments, but Whelan and Naccache have put potentially sensitive information within the reach of the unwashed masses.  Almost as bad as the exposure of compromising words is the confusion that’s likely to arise as media organizations mine ambiguous results from blotted documents and select whichever “hits” match the conspiracy theory du Jour.  What’s good for public transparency is sometimes bad for public safety.

There’s talk of changing document censorship techniques, but no easy answer exists for files available primarily on paper.  Perhaps this will add another incentive to move all government records into the electronic age.  I have a feeling this little academic pebble will make some interesting ripples.

It’s a shame that instead of blotting, Nixon had the paranoid prescience to make sure that his more picturesque utterances were replaced with “[expletive deleted]” when his White House tapes were transcribed.  A “Dublinized” version of those conversations would make for mighty good C-SPAN.