In Search Of Randomness

Our world runs on randomly generated numbers and without them a surprising proportion of modern life would break down. So, why are they so hard to find?

The friends did their best to explain what they were looking for – a really crackly radio. You know, the kind that blares a hail of static between stations as you turn the dial. The shop salesman didn't know what to say.

"I think he thought we were quite crazy," recalls Mads Haahr. It was 1997, and he and his pals were nosing around a Radio Shack outlet in Berkeley, California. Most of the radios on sale had noise filters that cut out the crucial crackles they were looking for. After a little persuasion, though, the salesman agreed to let Haahr and his friends listen to one of the cheapest devices he had in the back of the shop.

As they slotted a couple of batteries into the small, grey, $10 radio, a wall of buzz burst forth. It was noisy as hell. "We were jumping up and down," says Haahr. That little radio was, potentially, about to make them rich. Haahr and three of his friends had been working on gambling software – digital slot machines and blackjack games that they wanted to host online. Back then, online casinos were just beginning to take off.

Haahr knew that they would need to be able to generate reliably random numbers. Endless streams of digits that would determine what slots came up when you yanked the virtual lever, or what cards got dealt in an online poker game. If these things weren't random, the digital casino wouldn't be very fair and players could even try to beat the system by looking for predictable patterns in the games.

And so the four friends were seeking a source of randomness that they could all agree was trustworthy. Something that, by definition, couldn't be biased. The idea had hit Haahr like a tonne of poker chips – the hiss of a dirt-cheap analogue radio.

The noise blurted out by such a device is actually a messy signal shaped by lightning and electromagnetic activity in the Earth's atmosphere. That's what generates the blast of unpredictable static. Haahr had planned to have a computer listen to all that gibberish, convert the ups and downs into little ones and zeroes, also known as bits, and then use that to produce strings of random numbers – something like 4107567387. Which, to take a simplified example, could determine that the next card you get dealt in your online poker game is, say, the six of spades.

(Oh, you were holding out for a five of clubs. Didn't you know? You gotta know when to fold 'em.)

There are some things that computers, for all their prowess, don't do well – and one of them is randomness. Sure, computers spit out data all the time, why not random numbers? The problem is that computers rely on internal mechanisms that are at some level predictable, meaning the outputs of computer algorithms eventually become predictable, too, which is not what you want if you're running a casino. The same issue can cause headaches for cryptographers. When you encrypt information, you want the keys to the code to be as random as possible, so that no-one can work out how you garbled the original text since that could allow them to read the secret message.

People have long sought external sources of randomness as the basis of random number generators. In this search for true randomness, they have looked practically everywhere for chaotic phenomena that can't be predicted or manipulated. They have listened to the racket of electrical storms, captured pictures of raindrops on glass, and played with the tiniest particles in the known Universe. The search is far from over.

In the end, the little grey radio didn't make Haahr and his friends rich after all. The online gaming business was too much in its infancy back then for the young entrepreneurs to make a killing out of it. But the random number generator they built was, they reasoned, still useful. So Haahr made it public at random.org, where it has been churning out random numbers ever since. It gets a lot of visitors.

"One I can mention is the San Francisco Mayor's Office," says Haahr. "They use our service to draw winners who are lucky enough to get affordable housing."

Other users include people who run local community lotteries. They choose the winning numbers every week on Haahr's website. Scientists have even used the online number generator to randomise participants in experiments. Marketing firms that give away prizes to consumers have also chosen their winners with the help of random.org. "People use it for drug screening, for example," adds Haahr. "Selecting employees randomly." The site also has a facility for choosing a random password. And yes, some online gambling services rely on random.org, too.

One man even says he turned to it to help him choose which discs from his 700-strong CD collection to put into his car each week.

All of these results, including, in some cases, life-changing outcomes of draws or selection processes, are derived from atmospheric activity picked up by a bunch of radio receivers. The original $10 radio has long been misplaced, confesses Haahr. Over the years, he and his colleagues set up more advanced equipment to yield high-quality atmospheric noise and, currently, the site relies on nine large receivers in different geographical locations.

If you never enter the lottery or have no intention of taking part in a clinical trial, you might think that random numbers don't really matter to you. But you'd be wrong.

Every time you choose a new password, even one you think of yourself, a computer adds another chunk of data to it. This scrambles the password for storage meaning that, if someone hacks a database and steals your password, they can't easily unscramble it and use it to access your account. That chunk of data added to the password is called a salt and it is derived from a random number.

"We're using them every day without really knowing," says Alan Woodward, a computer security expert at the University of Surrey.

Random numbers are essential for securing information, he points out, since they are used whenever a computer encrypts data so that it looks to any casual observer like mere gobbledegook. When you visit a website that begins "https://", for example, you're asking your computer and the server that stores the website to, among other things, generate some random numbers, exchange them and then use them to encrypt the data sent back and forth as you load the website and go on to use it. (This is an enormous simplification of the exchange that takes place in just a few milliseconds, but you get the drift.)

When sensitive data is flying around computer networks, especially those accessible by the public, it's essential to secure that information. Cloudflare, a tech firm that provides cloud security services, uses a lot of random numbers at its data centres. The company has sought some eye-catching ways of generating randomness – including a collection of lava lamps.

"It almost started as a joke and then we said, 'Wait a minute, we could actually do that,'" says John Graham-Cumming, chief technology officer. At Cloudflare's office in San Francisco, a camera on the ceiling is pointed down towards a wall of colourful lava lamps. "The motion of those lava lamps, the blobby, oily, waxy thing inside, is not predictable," explains Graham-Cumming. That means that the camera can take pictures of the blobs at intervals, which are then converted into a series of numbers – more or less based on the shape and position of the blobs. This idea, first demonstrated by a company called Silicon Graphics in the late 1990s, is one of multiple methods that Cloudflare has up its sleeves for generating random numbers to secure information.

The list of things people have turned to in the pursuit of random numbers is deliciously odd. One software engineer realised when out walking on a wet day that the raindrops falling on his glasses might provide a suitable source of randomness, so he simulated the patterns via a short piece of code as an experiment. Someone else tried capturing the activity of bubbles in their fish tank as a basis for random number generation. Another approach relied on the unpredictable behaviour of a kitten, its movements having been captured on a webcam.

One group of researchers even sought randomness by looking at the unique genetic sequences contained within DNA molecules inside all living things.

Then there are the many efforts that involve detecting the clicks of radioactive decay, picked up with Geiger counters, for example. You can't predict exactly when an atom will decay and release subatomic particles that set of the Geiger counter, meaning this is considered a good source of randomness. There's even a project that employed a banana to make a number generator – since the bendy fruit is known to be mildly radioactive.

In 2016, the New York Times mentioned the example of a young computer gamer who found a way of making a kind of random number generator in Minecraft. The gamer had constructed a sort of tournament for his friends within the world of Minecraft but he wanted to be able to trigger a trap at random intervals – to try and catch out contestants in the game. And so, he decided to build enclosures and within them enslave virtual cows called mooshrooms because they walk around in a random pattern. Whenever a mooshroom stepped on one of the pressure plates the gamer had installed in the floor of their enclosures, that would trigger a trap in the game-within-a-game that he had designed. An "ingenious" solution, as the New York Times put it.

The publishing continues..

- Author: Chris Baraniuk, BBC