Synaptic Sugar

While shopping online I was once asked by a business tracking website to complete a survey about my experience with the online store I had just visited, with the chance to win monetary prizes if I accepted to participate. This is nothing new, but in the terms and conditions to accept for taking the survey (which one should always read) I found something peculiar, which I quote:

1. Who can enter: Open only to legal residents of the United States (excluding Puerto Rico) and legal residents of Canada (excluding Quebec) who are 18 years of age or older.

[...]

4. Timing: To be eligible to win, entries must be received by 5:00 p.m. PT January 18, 2008.

Sponsor reserves the right to verify eligibility qualifications of any winner. If a Canadian resident wins a prize, that person must also answer correctly within a 5 minute time period a mathematical skill-testing question without the benefit of any human, mechanical or electronic calculating devices before the prize will be awarded.

[...]

I assume Canada must have a law that requires citizens to actually earn the prizes they win, and not just have them donated by Lady Luck; but by the way these rules are worded, it almost sounds like somebody enjoys giving the poor Canadians a hard time.

(By the way I didn’t participate in the end, for other reasons.)

Two posts in a day! There’s always a first time I guess. The website Haltadefinizione, which gathers very, very detailed images of important works of art digitally captured, restored and preserved by a company known as HAL9000, has made available a 16 billion pixels image of The last supper by Leonardo da Vinci. It’s surely something to look at, so go ahead and follow my links.

A mysterious single blast of radio waves was observed in archived imagery data from 2001 detailing the portion of space containing the Small Magellanic Cloud; its cause: unknown. The burst may look insignificant at first, a single 5-millisecond blip during a 480-hour observation, but what makes astronomers excited is the fact that its location and wide dispersion indicate it must come not from the Cloud, but rather from very far away, about 3 billion light years from Earth; unfortunately, it’s impossible to pinpoint it to any galaxy or celestial object, making it harder to find out what caused it. However, Duncan Lorimer, an astrophysicist at West Virginia University in Morgantown and the National Radio Astronomy Observatory who led the team behind this discovery, says events like this could be detected a couple hundred times per day, if only they were looked for with the right equipment.

Why is a finding like this important? One hypothesis is these waves were emitted when two neutron stars collided or during the death of a black hole, meaning their observation could help find proof of the existence of the gravitational waves predicted by Einstein’s theory of relativity (which theoretically should be emitted by titanic events like those) but were never directly observed. In turn, these could teach us something more about black holes and ultimately about the inner workings and origin of the Universe — surely no small result for a 5-millisecond blip and worthy of ending up in my gallery of Mysterious Mysteries.

This is a picture of a ring of dark matter composed from images caught by the Hubble space telescope. The original high-resolution picture and story appear on the NASA website.

Edited on May 22 at 12:57 PM

Steganography, like Cryptography, is a science that has as its objective the transmission of “secrets” from a sender to a recipient. Between these two sciences lies a substantial difference: the former allows a message to be transmitted as cleartext, but hidden inside other kinds of messages that are apparently harmless (cover messages); in the latter case, the tranmission of a secret message is evident, but the message itself is encrypted and secrecy lies in the difficulty to obtain the original cleartext for whoever isn’t the sender or the intended recipient.

Throughout the centuries Steganography has been employed in a wide variety of ways, to warn Sparta of the incoming Persian attack for example, or to hide messages during World War II, and it can also be used in software with digital images, audio or text. When done properly, inserting a secret message (payload) in a cover message does not produce visible differences in the cover message itself, but by comparing a suspect message with the original unchanged cover message, when feasible, it is possible to discover the payload or at least its existence.

The little game I posted a few days ago, "A simple quiz", was a little unfair: the two images were different as stated, but the differences weren’t visible to the naked eye. I had hidden a text file in the image to the left, producing the image to the right, with steganographic techniques; the text file contents can be seen in the comments below that post, where the solution has been revealed by Henomis (congratulations on finding it!). To do it I used a program called Steghide (but there are several others available), for which I wrote a couple years back a GUI (ie. a Graphical User Interface) in C++, SteGUI, using the FLTK library. Both Steghide and SteGUI are open source software freely available on SourceForge.

The quiz was actually simple once one had the intuition of trying a steganalytic approach (which I knew wouldn’t come to mind to many people), since the payload wasn’t compressed, encrypted, nor protected with a passphrase, all things you could do with Steghide. To find out more about Steganography or SteGUI, you can visit the project website, also linked in the sidebar. You might find the information useful — after all, who knows what I could hide next, or where?