Why Bitcoin is not as anonymous as most users think

People who use Bitcoin to ensure their purchases remain anonymous may want to reconsider their reliance on the online peer-to-peer currency, say researchers who have investigated the network of Bitcoin transactions.

Users exchange bitcoins by sending them to the recipient's wallet address, a sequence of alphanumeric characters that serves as the public key in a cryptography system. Anyone can view every transaction, but since there is no public record linking addresses to users and users can have any number of addresses many people assumed it would not be possible to trace transactions to a particular individual.

Now Fergal Reid and Martin Harrigan of University College Dublin, Ireland, say this assumption is wrong. They separately mapped the network of Bitcoin transactions and the network of users, then looked for external information that could help make links between the two. For example, WikiLeaks has tweeted its wallet address asking for donations, so the researchers could identify bitcoins flowing in and out of its wallet.

The pair used the reported theft of $500,000 worth of bitcoins as a case study, discovering a number of links to other users. The thief stole 25,000 BTC from the victim, known as "allinvain" on the Bitcoin forums, then later sent 0.31337 BTC, which looks like the word "elite", to a wallet owned by the hacking group LulzSec. Another unknown user is also connected to both LulzSec and the victim - this user donated to the hacking group one day before the theft, and was a member of the same "mining" group as the victim, in which Bitcoin users work collectively to generate new coins.

Reid and Harrigan don't actually identify the thief, but they suggest that a centralised service with more user data, such as one of the many Bitcoin exchange websites, could use similar methods to learn more about the users involved. "We don't set out to to de-anonymise the thief - we are researchers, not law enforcement," said Reid in response to questions on a blog post about their work, adding that while it is possible to use Bitcoin anonymously, "you don't get this anonymity automatically, and that most casual users of Bitcoin may not be anonymous, even though many of them may believe they are".

FIFA to retest nine goal-line technologies

It was England footballer Frank Lampard that did it. His infamous disallowed goal against Germany at the last World Cup in 2010 reignited the debate about whether goal-line technology has a place in football.

Now FIFA, the sport's world governing body, has announced that it is to test the nine best candidates to see which (if any) could be in place in time for the World Cup in 2014 in Brazil, according to the Associated Press.

However, the demands placed by FIFA on the candidate technologies - which have not been named but are all based in Europe - are pretty onerous. The referee must know within a second what the verdict is, either with a vibration or visual signal sent to something he wears on his wrist. Crucially, the verdict must be 100 per cent accurate, a condition that current systems have so far found difficult to meet.

The two main technologies involved include vision-based system like Hawk-Eye - already used in cricket and tennis at the highest level - which uses six high-speed video cameras to track the ball's flightpath. A second approach is to install a microchip in the ball which senses a magnetic field as it crosses the goal line, sending a signal to the referee.

The last series of tests in March were rather underwhelming: none of the nine technologies tested at Swiss Federal Institute for Materials Research managed to reach FIFA's required benchmarks. The new tests, at the same location, will take place between September and December this year.

A web browser for your calculator

Smartphones, tablets, televisions and of course, the trusty old PC - these days you've got a lot of options when choosing how to access the web. Now there's a new option: the graphics calculator. 

Gossamer is a web browser for Texas Instruments calculators created by Christopher Mitchell, a computer scientist at New York University. Websites are formatted and sent to the calculator by an external server. At the moment the browser can only access sites on a pre-defined list, but Mitchell is working on a new version that will let users input any URL.



As you might expect, the retro-browser isn't Mitchell's first venture into programming graphics calculators. He claims on his website to be the "world's most prolific graphing calculator programmer". He very well may be: He previously developed networking software that allows calculators to connect to other devices, an essential pre-requisite to a web browser, along with other programs including a media player and video games.

via TechCrunch

Transparent battery makes see-through phones possible

A see-through smartphone you can roll up and stick in your pocket – how about that for a must-have product? It's now one step closer to reality, thanks to the development of a transparent battery.

Transparent screens, circuitry and keyboards have already been developed in an effort to produce see-through devices, but the bulk of any phone is its stubbornly opaque battery. Now, Yi Cui, who led the research at Stanford University, California, says his new battery is the last piece needed to make transparent gadgets.

Other transparent components are essentially just ultra-thin versions of their opaque counterparts, but an equivalently slimmed-down battery wouldn't store much energy. Instead, Cui and colleagues created a grid of electrodes, embedded it in a transparent electrolyte gel and sealed it in plastic. The grid lines are smaller than the resolution of the human eye, rendering the entire thing transparent, while the gel allows the battery to be flexible.

"The transparency is tuneable, so it could be as transparent as glass, in principle," explains Cui. "However, there is a trade-off between transparency and energy density. A reasonable transparency is 50 to 80 per cent." Such batteries store between a third and a half of the energy of an ordinary battery of the same size, but Cui says increasing the thickness would allow them to provide comparable levels.

Cui believes we could see transparent batteries in consumer devices in the next two to four years, depending on how easy it is to scale up the manufacturing process. The see-through components also have a scientific application, however: researchers can use optical detecting tools to study a battery's chemical reactions as they happen, which previously was impossible.

Andrew Flewitt, who researches plastic electronics at the University of Cambridge, says the battery will be key in producing transparent devices. "It's a really important step along that road. I've not seen anyone even attempt to put that piece of the jigsaw in yet," he says, though he adds that integrating the battery into a fully flexible device is likely to be an extra challenge.

Touchscreen keyboard morphs to fit your typing style

Paul Marks, senior technology correspondent

Typing on a touchscreen is not one of life's pleasures: the one-size-fits-all nature of most virtual keyboards is a hassle that puts many of us off using them. I've lost count of the number of times I've seen journalists put down an iPad, for instance, and pick up a laptop or netbook to do some serious notetaking or writing.

IBM, however, says it doesn't have to be that way. In a recently filed US patent application, three IBM engineers posit the notion of a virtual keyboard in which the position of the keys and the overall layout is entirely set by the user's finger anatomy. That way, they argue, people will be better able to type at speed, with all keys within comfortable range and so end up, with fewer errors. 

After an initial calibration stage, in which the keyboard asks users to undertake a series of exercises to set response time, anatomical algorithms get to work, sensing through the touchscreen the finger skin touch area, finger size and finger position  for the logged in user.

As this information is gathered - IBM does not say over what period this learning takes place - the virtual key buttons are automatically resized, reshaped and repositioned in response.

The patent shows a keyboard with some keys subtly higher than others, and with some fatter than others. This "adapts the keyboard to the user's unique typing motion paths" governed by their different physical finger anatomies, says IBM, which suggests the idea being used in both touchscreen and projected "surface computing" displays.

There does seem scope for such ideas. In a review of the Apple iPad, review websiteMacInTouch said: "A touch typist found it frustratingly glitchy versus a real keyboard, producing all sorts of ghost characters when the screen repeatedly misinterpreted his fingers' intentions."

Perhaps anatomical profiling is just what's needed. 

Dizzy moon lander misses public debut

(Image: NASA)

It was billed as the beginning of a "new era" of private companies racing to reach the moon, timed seamlessly to coincide with the end of NASA's 30-year shuttle program and toasted with champagne, violinists, moon-shaped biscuits and even a song. But what was supposed to be the first public flight test of a commercially developed robotic lunar lander  - an entrant to theGoogle Lunar X Prize  - ended last night with a good dose of sod's law and more fizz than bang.
 
The flight test of the $40 million lander  - developed by the one-year-old Silicon Valley based start-up, Moon Express, and scheduled for demonstration in front of a crowd of luminaries, investors, and journalists - was called off at the last minute after engineers couldn't fix a problem with a new gyroscope. It meant the lander was convinced it was spinning in the opposite direction to the one it was actually turning. The expectant audience had to make do instead with video footage of the lander being privately tested last month. 

The hiccup is a little disappointing admits Barney Pell, the former NASA research and development manager who co-founded the company and is its chief technology officer. But it is also not wholly unexpected given just how fickle high-tech projects can be, he says. The lander is supposed to be more precise, better able to avoid hazards when it lands and have more thrust for its lighter weight than any previous landers.

"It would have been nice to share with everyone," says Pell, "But the reality of engineering is that things take a while and whenever you are about to demo something it will break just at that moment." 

The demonstration comes as the Google Lunar X Prize  - a $30 million competition for the first privately funded team to send a robot to the moon - heats up. The 29 teams currently in the race have until 2015 before the money disappears.

Many are trying to create entries that will have a use and market beyond the contest and Moon Express doubtless has one of the most ambitious long term aims: to mine the moon for rare metals. There is more platinum on the moon than all of planet earth, notes Pell, adding he believes moon mining could be economical, in some cases now, and it has the added bonus of being environmentally benign because "nothing lives there".

Engineers plan to fix and re-test the lander today. We will make it to the moon, insists Pell.

Spotting the flaws in casino card-shuffling machines

Ever feel like others at your poker table seem to have an unfair advantage? Like you were up against a team of expert card counters like the notoriously successful MIT Blackjack team? 

Well, you might be, but at least you can take comfort in the fact that a team of statisticians from Stanford University, US, are now making things fairer. They recently discovered that cards dealt by an automated huffling machine  - designed to deal a random set of cards - were more than twice as easy to predict than a human-shuffled pack.

Automated card shufflers have been helping inept - and unlawful - dealers since the 19th century, though it's only in the last 50 years that they have been widely adopted by casinos. Now, though, the machines are sophisticated devices, rented to casinos for around $500 per month per machine - and with one on every card table, that makes for a profitable industry. 

Statisticians help casino equipment manufacturers ensure that their shuffling machines spit out cards that are entirely randomly ordered to help foil cheats - and give the average punter like you or me a passing chance at winning a hand. 

But, like poker hands, not all automated shufflers are alike, and, like most of my poker hands, some don't work as well as others. The latest trend in card-shuffling circles is the shelf shuffler: a machine which replicates the human riffle shuffle by randomly placing cards on one of a number of shelves, before re-assembling the deck by taking piles from the shelves, again in random order.

The team of Stanford statisticians was contacted by a manufacturer of casino equipment to test a new shelf shuffler, which was already designed and built. The basic tests to ensure randomness of cards coming out of the machine had, apparently, been carried out by the engineers, and the results seemed satisfactory. All the manufacturers wanted to do was double-check that a deck could be passed through the machine and then be used without concern in the casino.

They did not, however, bank on getting the hand they were dealt.

The high-rolling statisticians at Stanford took the task seriously. They set about testing the statistics on which the machine was based, and performed tests to measure how random the machine's results were. They found that a knowledgeable player could guess about 9.5 cards correctly in a single run through a 52-card deck from the machine, compared to 4.5 for a properly shuffled deck.

That boiled down to some cold, hard advice for the manufacturers: their machine's shuffling was not random enough to be used in a casino. In fact, the statisticians have reported that the the president of the company responded "We are not pleased with your conclusions, but we believe them and that's what we hired you for."

Whatever your game, stopping crooked dealers and card-counting players has to be a good thing. Just make sure that, next time you visit the casino, you sit at a table with Stanford statisticians - and steer clear of those MIT card counters.