I received a letter the other day - with a stamp affixed to the envelope.
Nothing unusual there, I hear you say and you’d be right - it is traditional to put stamps on letters. In fact, the world’s postal services are downright sniffy about delivering letters without stamps. Here is the item in question:

Now stamps come in all shapes and sizes; usually with pictures of famous people, birds or flowers. I’ve even seen stamps with record cover artwork and characters from The Simpsons on them so, by comparison, the one above probably seems pretty dull…
Except for the square thing on the left hand side. It’s called a Data Matrix and is a kind of two-dimensional barcode. You can cram quite a lot of information into a Data Matrix. For example, this one:

contains “Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam”. Not bad for a little array of black and white squares.

All of which got me thinking - what’s on my stamp?

I did a bit of ferreting about on t’interweb, looking for a site that could decode it for me, with limited success. Just finding a site that would acknowledge my picture even contained a Data Matrix was a problem and, when I eventually did find one, the results it returned seemed to be complete garbage - just a jumble of symbols and ‘unprintable’ characters. One could be excused for thinking that the data had been encrypted, but why would anybody encrypt a postage stamp?

Then it dawned on me: stamps are money! They pay for the transportation of an item through the postal system. But this type of ‘money’ is one that anyone with a bit of software and a reasonable printer can create (i.e. ‘forge’) for themselves. By encrypting the data, you ensure that the automated sorting machinery can spot forgeries and deal with them accordingly - at least, this is what I figure.

So I guess I’ll never know what it contains (though it’s probably something incredibly boring like: value, date / time / location produced, serial number, etc…).

However; for such an apparently dull stamp, it turned out to be really rather interesting.