Wednesday, February 19, 2014

The Highest-Denominated Bill Ever Issued Gives Value to Worthless Zimbabwe Currency
A 100-trillion-dollar bill, it turns out, is worth about $5.

That's the going rate for Zimbabwe's highest denomination note, the biggest ever produced for legal tender—and a national symbol of monetary policy run amok. At one point in 2009, a hundred-trillion-dollar bill couldn't buy a bus ticket in the capital of Harare.

But since then the value of the Zimbabwe dollar has soared. Not in Zimbabwe, where the currency has been abandoned, but on eBay.

The notes are a hot commodity among currency collectors and novelty buyers, fetching 15 times what they were officially worth in circulation. In the past decade, President Robert Mugabe and his allies attempted to prop up the economy—and their government—by printing money. Instead, the country's central bankers sparked hyperinflation by issuing bills with more zeros.

Sunday, February 16, 2014

Cryptic Crossword: Amateur Crypto and Reverse Engineering
Something that my friend had noticed was that when we scrambled a puzzle twice in a row, the two keys would be different, but only in the first half. The third and fourth digits were the same. At first I thought that this might be due to scrambling the same grid, but further exploration suggested that it was entirely due to temporal proximity. So naturally, I tried running two instances of the Across Lite program at the same time, and hit Alt-S S on both of them as quickly as possible. In this way I obtained two grids scrambled with the same key.

With this technique, I had my first inroad, a way to start making some actual progress in the investigation. I could now create two crossword grids that differed in some specific way, scramble them both with the same key, and then compare the results, seeing directly how a change input affected the scrambled output.