Call it an abundance of caution. A Microsoft research project has upgraded the encryption protocol that secures the Web to resist attacks from quantum computers—machines that are expected to have stupendous power but have never been built.
Governments and computing giants like IBM, Microsoft, and Google are working on quantum computers because tapping subtle effects of quantum physics should let them solve in seconds some problems that a conventional machine couldn’t solve in billions of years (see “Microsoft’s Quantum Mechanics”). That might allow breakthroughs in areas such as medicine or energy. But such machines would also be able to easily break the encryption used to secure information online.
Last year, Google began experimenting with hardware-based schemes for user-authentication, while Apple added two factor authentication to iCloud and Apple ID users. They began sending a verification code to users via a mobile number registered in advance.
Security pundits know that two factor authentication is more secure than simple passwords. As a refresher, “Factors” are typically described like this:
Something that you know (a password — or even better, a formula)
Something that you have (Secure ID token or code sent to cell phone)
Something that you are (a biometric: fingerprint, voice, face, etc.)
The Google project may be just another method of factor #2. In fact, because it is small (easily misplaced or stolen), it simplifies but does not improve on security. I suggest a radical and reliable method of authentication. It’s not new and it’s not my idea…
Back in 1999, Hugh Davies (no relation to Ellery) was awarded a patent on a novel form of access and authentication. It capitalizes on the human ability to quickly pick a familiar face out of a crowd. Just as with passwords, it uses something that you know to log in, purchase, or access a secure service. But unlike passwords, the “combination” changes with every use, and yet the user needn’t learn anything new.
Hoping to commercialize the technique, Davies joined another Brit, Paul Barrett, and formed Passfaces (originally, Real User Corporation). Incidentally, it is quite difficult to research Passfaces and its history. Web searches for “face recognition”, “access”, “authentication” and “patent” yield results for a more recent development in which a smart phone recognizes the face of authorized users, rather than users recognizing familiar faces. (Google, Samsung and Apple are all beginning to use face recognition on mobile devices). In fact, the Passfaces method is quicker, uses less resources and is far more reliable.
I have long been disappointed and surprised that the technique has never caught on. It is a terrific method with few drawbacks. Used alone, it is better than other methods of 1 or 2 factor authentication. Add a second factor and it is remarkably secure and robust.
How it Works:
When accessing or authenticating (for example, logging into a corporate VPN or completing a credit card purchase), you are presented with a tiled screen of individual faces. I prefer a big 15×5 grid = 75 images, but Passfaces uses sequential screens of just 9 faces arranged like the number pad on an ATM.
Just click on a few familiar faces. That’s all! Oddly, Passfaces discourages the use of known faces. Their research, with which I respectfully disagree, suggests that users should train themselves to recognize a few faces from the company’s stock library. In my preferred embodiment, users upload a dozen photos of people they know at a glance—preferably, people that they knew in the past: A 3rd grade music teacher, a childhood friend who moved away, the face on an oil painting that hung in the basement until Dad tossed it in the fireplace. Now, add the boss who fired you from your first job, the prom queen who dumped you for a football jock, and that very odd doorman who stood in front of a hotel in your neighborhood for 20 years. Photos of various quality and resolution, but all scaled to fit the grid. Some are black & white, perhaps scanned from an old yearbook.
Using my preferred example of 75 faces, suppose that 5 or 6 of the images are from your personal shoe box of old photos. The rest are randomly inserted from all over the internet. How long would take you to click on 3 of the 5 or 6 familiar faces in front of you? (Remember: They are old acquaintances. Even a spouse would have difficulty picking out 3 faces from your early life—as they looked back then). Surprise! You will click them instantly, especially on a touch screen. You won’t need even a second to study the collage. They jump off the screen because your brain perceives a familiar face very differently and faster than anything else.
Of course, the photo array is mixed in different ways for each authentication and it incorporates different friends from your original upload. In fact, if a user sees the same faces in the next few transactions, it is a red flag. Someone has spied on the process, perhaps with a local camera or screen logger. In legitimate use, the same faces are not recycled for many days and are never shown together on the same screen.
Facebook uses a variant of this technique when their servers sense your attempt to login from new equipment or from another part of the country. They show you individuals that you have friended, but that were uploaded and tagged by other users. If you cannot identify a few of your own friends, especially the ones with which you have frequent social contact, than it’s likely that your login attempt deserves more scrutiny.
I don’t know why Passfaces or something like it has failed to catch fire. Perhaps the inventor refuses to license the method at reasonable cost or perhaps he cannot find a visionary VC or angel consortium to more aggressively promote it. If I had invented and patented facial-array authentication, I would attempt to market the patent for a short time focusing on very large network companies like Microsoft, Google, Cisco or Akamai. If I could not license or sell the patent quickly, I would hesitate to go it alone. (I have tried that route too many times). Instead, I would place it in the public domain and profit by being the first, and most skilled practitioner at deployment. I would train and certify others and consult to organizations that use or commercialize the technology.
I used this approach in promoting my own patent which describes an economic barrier to spam (after failing to exploit the invention with my own company). Later, I started with this approach in my research on Blind Signaling and Response and on Reverse Distributed Data Clouds. I recognized that rapid adoption of transformative technology like facial grid authentication, can be thwarted by defensive IP practice.
« Branching somewhat off topic, a developmental biologist at Imperial College in London, has published a proof that Saira Mohan has the world’s most beautiful face, irrespective of the observer’s race. That’s Saira at left. Her mother is French/Irish and her father is Hindoo.
__________ Philip Raymond is Co-Chair of The Cryptocurrency Standards Association [crypsa.org] and chief editor at AWildDuck.com. He consults to cloud storage vendors in areas of security, pri– vacy & network architecture, but has no ties to Passfaces or the authentication community.
Biometric technology was once the stuff of sci-fi—how many movies show someone having their hand or eye scanned to get entry into a secured facility? But today biometric tech can be found in millions of people’s pockets—as the fingerprint scanner on an iPhone.
When I was a freshman at Cornell University some decades ago, I had a memorable teaching assistant for CS100, the entry level computer programming course taken by nearly every student in Engineering or Arts & Sciences. Gilles Brassard, a French Canadian, is now a chaired math professor at Université de Montréal and a preeminent cryptographer. He has also been inducted into the Royal Order of Canada. I am told that this is a bit like being knighted. In fact, this highest of civilian honors was established by Queen Elizabeth.
The author with Gilles Brassard in 2014
Gilles was a graduate student at Cornell in the mid ’70s. Back then, public key encryption was a radical concept. Named for three MIT professors who described it, RSA is now it is at the heart of every secure Internet transaction. Yet, the new generation of cryptographers refers to RSA as “classical cryptography”. The radicals have moved on to Quantum Cryptography. Gilles and his collaborator, Charles Bennett, are the pioneers and leaders in this burgeoning field. No one else is even pretender to the throne.
In its simplest terms, quantum cryptography achieves a secure communication channel because it relies on a stream of individual particles or “quanta” to convey information. If information is sent without any fat at all—just the minimum physics that can support the entropy—then any eavesdropping or rerouting of a message can be detected by the recipient. Voila! Perfect authentication, fidelity and security. Communication is secure because any attack can be detected.
But when you begin to experiment with gating individual quanta of anything, you are typically working within a world of minute, elementary particles—things like photons or electrons with properties that change as they are measured. And the issue of measurement doesn’t just invoke Heisenbeg (he demonstrated that measurements change a property being measured), but also superpositioning of states that resolve only when they are observed. Say, Whaaht?!
Perhaps, we are getting ahead of ourselves. The goal of this article is to share a strange, thoroughly unexpected, awe-inspiring, yet repeatable experimental results achieved by quantum physicists. I am no expert, but given a sufficiently lay explanation, marvel with me at a baffling outcome. It will shake your perception of reality. It suggests that science and math are not as black and white as you believed.
The EPR Paradox Albert Einstein worked for years to develop an understanding of entangled particles that was consistent with his earlier work in special relativity. By the mid 20th century, physicists were reasonably certain that information could never be conveyed faster than light. It’s not just the math that convinced them. It was the crazy things that would ensue if light speed was not a universal speed limit…
If information—mass or energy, particle or wave, substantive or pure thought—if any of these things travels faster light, then given the time dilation of things moving in relation to each other, very unlikely things would be possible. For example:
If information travels faster than light. it would be possible to deliver a reply to a message that had not yet been sent
If information travels faster than light, it would be possible to send a message back in time and prevent your parents from meeting each other
So the math that imposes a universal speed limit also preserves our concept of reality. Sure, we can accept that energy and mass are fungible. We can even accept that distance and time are malleable. But time paradoxes defy common sense and beg for a solution that prevents them, altogether.
When the most reasonable explanation of quantum entanglement collided with our understanding of special relativity, efforts to reconcile the two theories or arrive at a unifying model became known as the EPR Paradox, named after Einstein and his colleagues, Boris Podolsky and Nathan Rosen. Given assumptions considered axiomatic, the math suggests that information passes between entangled particles faster than light — in fact, instantaneously and at any distance. Near the end of his life, Einstein reluctantly acknowledged that there must be an error in math, or in basic assumptions, or that some undiscovered, rational explanation could resolve the paradox. Ultimately, he dismissed the notion of particles synchronously and instantly communicating with each other as “spooky action at a distance”. Just as his other memorable quote, “God doesn’t play dice with the world”, the two phrases are indelibly inscribed onto the great physicist’s epitaph.
Before humans could travel to the moon (about 1.3 light seconds from earth), researchers tried to test Einstein’s theory. But even with precise instruments to measure time and distance, it was too difficult in the 1930s and 40s to create, transport and measure characteristics of elementary particles and then discriminate their behavior in such close proximity.
Back then, Einstein assumed that we would measure wave collapse positions or particle momentum. But today, scientists are more keen on measuring another quantum phenomenon: particle spin or photon polarization—or particle destruction. These properties are more easily changed and measured. In the 1960s and 70s, the EPR paradox returned to popular inquiry when physicists John Stewart Bell—and later Lamehi-Rachti and Mittig, conducted experiments that supported Einstein’s original thesis. That is, faster-than-light communication seemed to take place.
So, given appropriate experimental methodology, could it actually be possible to receive a package before it was sent? This is, after all, the disturbing conclusion of faster-than-light communication.
Probably not. But the experimental result is more shocking than “Yes” and way more interesting than “No”. In fact, the outcome to recent experiments force us to confront our understanding of causality. It makes us wonder if reality is an illusion. It shatters our concept of time and space even more than Einstein’s more famous theory of relativity.
Since measurements made in nanoseconds are difficult to visualize, I shall illustrate the experiment and the surprising results by stretching the distance involved. But this is not a metaphor. Actual results actually play out as described here. Continue below image…
The Experiment
Suppose that I create a pair of entangled particles. It doesn’t matter what this means or how I accomplish the feat. I wish only to test if a change to one particle affects the other. But more specifically, I want to separate them by a great distance and determine if a change to the local particle influences the remote particle instantly, or at least faster than accounted for by a light-speed signal between the two of them.
If you could construct such an experiment, it seems reasonable to assume that you would observe one of four possible outcomes. The results should demonstrate that the remote particle is either:
not affected at all
affected – apparently instantly or nearly in synchrony with the first particle
affected – but only after a delay in which a light speed signal could reach it
uncorrelated or inconsistently correlated with it’s entangled mate
The actual result is none of these, and it is almost too stunning to contemplate. In fact, the particle is highly correlated, but the correlation is with the observer’s cognition. But again, I am getting ahead of myself. Let’s look at our experimental set up…
I send an astronaut into space with a box that contains an experimental apparatus. The astronaut travels a distance about as far away from Earth as the sun. It takes about 8 minutes for light (or any message) to reach the astronaut. The box contains the “twin” of many paired particles back on earth. Each particle is trapped in a small crystal and numbered. The box also contains an instrument that can measure the polarization of any photon and a noisy inkjet printer that can be heard from outside the box.
Back on the earth, I have the mate to each paired photon. All of my photons exhibit a polarity than can be measured and expressed as a 2-D angle with any value from 0 to 360 degrees. Our test uses polarized filters to measure the angle of polarity and is very accurate. We can record 4 digits of precision. For the purpose of this test, it doesn’t matter if our measurement affects a particle or even if it destroys it, because we can repeat the test many times.
Clocks on the earth and at the spaceship are synchronized, and the ship is not moving relative to the earth. It is effectively stationary. On earth, each numbered photon is disturbed exactly on the hour. At the spaceship, an astronaut measures the polarity of a paired photon one minute before and one minute after each hourly event.
We know that our photons all begin with a polarity of 15.48 degrees as measured relative some fixed and rigid orientation. The astronaut confirms this with each photon tested before the hourly chime. But at each hour (say 3PM in New York), we disturb a photon on earth (radiate it or pass it through a filter). This changes its polarity.
Suppose that the earth lab determines that a photon was changed at 3PM from a polarity of 15.48° to a polarity of 122.6°. (Any new polarization will do).
Recall that the spaceship is 8 light-minutes away. We wish to determine if photon pairs communicate more quickly than the speed of light. Question: If the astronaut tests the polarity of the paired photon at 3:01 PM (just after its mate on the earth has been altered), do you suppose that he will still detect the original spin of 15.48°? Or will he detect the new spin of 122.6°?
The answer is more startling than either outcome. In fact, it leaves most people in disbelief or outright denial. (Yes…You are being set up for a surprise. But what is it?!)
To make things more interesting, let’s say that you cannot see the results. The box is sealed during the experiment, but you can hear the printer within the box as it prints the polarity after each test. Each time you run the experiment, you unplug the printer right after you hear it print a result. Then, you open the box and read the results.
Spookiness at a Distance
If you open the box less than 8 minutes after the hour (that is, less than the time that it takes light to travel from earth to the astronaut), the printout will always show a polarity of 15.48°. If you open the box after 8 minutes, you will always see a polarity of 122.6°. In both cases, the test was completed and the result was printed in the first minute after the photon on earth was shifted to a new polarization.
Wait! It gets better! If you eventually learn to distinguish the different sounds that the printer makes when it records either result, it will always print 15.48°, even if you wait 8 minutes before actually looking at the print out. The fact that you found a way to ‘cheat’ apparently changes the outcome. Or at least, that is the conclusion that a reasonable person would make when presented with knowledge-induced causality. It’s either that—or we are all crazy.
But quantum physicists (and cryptographers like Gilles) have another explanation. They point out that Einstein’s theory of special relativity doesn’t actually prohibit faster than light phenomena. It only prohibits faster than light communication. If the thing that happens instantaneously cannot be pressed into conveying useful information, then it doesn’t violate special relativity! That is, perturbations applied to one part of a quantum entangled pair are apparently instantaneous, but an observation or experiment on the remote twin will not produce a result that allows you to determine the new state until sufficient time for a light beam to pass from one to the other.
Alternate explanation: This one is known as “Schrödinger’s cat”. In my opinion it was contrived to support both quantum mechanics and the EPR paradox. It states that the paired photon simultaneously existed at both polarities until someone opened the box or otherwise learned its state. That is, the observed result was not a real thing, until the observation forced it to collapse into reality. Common sense says that this explanation makes no sense! And yet, it neatly resolves a lot of mathematics. Go figure!
Here is another explanation. I like this one better… Perhaps time is not an arrow that always moves in one direction and one speed. In contradiction to our intuition (based on a limited set of human senses), perhaps we are not continuously pushed forward at the tip of that arrow. –What if the science fiction about space and time being folded is true? –Or perhaps… Oh Heck! I’ll go with the first explanation: From our perspective, entangled particles change simultaneously, but mysterious forces of nature don’t allow us to observe the change until the laws of special relativity allow it. Why is that?… Because if we could observe information before it was ‘legal’ to do so, then we could change the past.
The take away to this experiment is that just like wave velocity, some things move faster than the speed of light, but useful information cannot do so. For useful information, light is still the speed limit.
Quantum physicists do not typically use my thought experiment, which I call Hidden Printer Result. Instead, they explain that Bell’s experiments prove that the spin measurement distant, entangled particles demonstrates they are connected in a spooky way (because the detected spin is provably opposite for each measurement)—but that Einsteien’s theory is preserved, because individuals measuring particles cannot know that their measurements are correlated until they communicate or meet. That communication is still restricted to light-speed limits, and therefore, useful information did not violate special relativity.
The Hidden Printer Result is a way in which we laypeople could observe and marvel at the transmission of unbelievably fast, but ‘useless’ information. It is a valid experimental setup that allows us to better comprehend that which defies common sense.
This Youtube video provides a more conventional, but more complex explanation of quantum entanglement and the EPR P
Gilles Brassard is not a physicist, but a computer scientist and cryptographer. Yet he has received awards that are typically given to physicists. His experiments and those by scientists around the world render a layperson like me dumbstruck.
Of course, Gilles didn’t ship an inkjet printer into space with half of an entangled pair (my experimental construct). Instead, he measured and recorded a particle state in a way that is self-encrypted. He then he sent the encryption key from the distant particle that had been disturbed. Even though the key is just two bits (too little to contain a measurement of photon spin), the old spin was observed if the key was applied before the time it would have taken to classically transmit and receive the information.
Just as with my experimental setup, results are almost too much to wrap a proverbial brain around. But truths that are hard to believe make great fodder for Lifeboat members. If my non-scientific, jargon free explanation gets across the results of the EPR experiment (actually, it is at the leading edge of my own understanding), then you are now as puzzled and amazed as me.
The National Security Agency knows Edward Snowden disclosed many of its innermost secrets when he revealed how aggressive its surveillance tactics are. What it doesn’t know is just how much information the whistleblower took with him when he left.
For all of its ability to track our telecommunications, the NSA seemingly has little clue exactly what documents, or even how many documents, Snowden gave to the media. Like most large organizations, the NSA had tools in place to track who accessed what data and when. But Snowden, a system administrator, apparently was able to cover his tracks by deleting or modifying the log files that tracked that access. Read more
Cryptocurrency aficionados have been discussing Bitcoin limitations ever since the blockchain buzz hit the street. Geeks toss around ideas for clearing transactions faster, resisting potential attacks, rewarding miners after the last coin is mined, and supporting anonymity (or the opposite—if you lean toward the dark side). There are many areas in which Bitcoin could be improved, or made more conducive to one camp or another.
Distinguished Penn State professor, John Carroll, believes that Bitcoin may eventually be marginalized due to its early arrival. He believes that its limitations will eventually be overcome by newer “altcoins”, presumably with improved mechanisms.
So, does progress in any of these areas threaten the reigning champ? It’s unlikely…
More than any other individual, Andreas Antonopoulos is the face of Bitcoin. We discussed this very issue in the outer lobby of the MIT Bitcoin Expo at which he was keynote speaker (March 2015). Then, we discussed it again, when I hosted his presentation at The Bitcoin Event in New York (also in March). He clearly and succinctly explained to me why it is unlikely that an altcoin will replace Bitcoin as the dominant—and eventually surviving—cryptocurrency…
It is not simply that Bitcoin was first or derived from Satoshi’s original paper, although this clearly established precedent, propelled it into the media, and ignited a grassroots industry. More importantly, Bitcoin is unlikely to be surpassed by an altcoin because:
Bitcoin is open source. It is difficult enough for skeptics to trust that an open source protocol can be trusted. Users, businesses, banks, exchanges and governments may eventually trust a distributed, open source movement. After all, math is more trustworthy and less transient than governments. Math cannot inflate itself, bend to political winds, or print future generations into debt if it is tied to a cap. But it is unlikely that these same skeptics will allow an inventor with a proprietary mechanism to take custody of their wealth, or one in which the content of all wallets cannot be traced back to the origin.
If we accept #1 (that a viable contender must be open source and either public or freely licensed), then Bitcoin developers or wallet vendors are free to incorporate the best protocols and enhancements from the alt-developers. They can gradually be folded into Bitcoin and adopted by consensus. This is what Gavin and the current developers at Bitcoin Prime do. They protect, enhance, extend, and promote. Looked at another way, when a feature or enhancement is blessed—and when 3 or 4 of the leading 7 wallets honor it, it becomes part of Bitcoin.
Bitcoin has achieved a two-sided network effect, just like Acrobat PDF. Unseating an entrenched two-sided network requires disruptive technology and implementation with clear benefits. But in the case of a widely distributed, trusted and universally adopted tool (such as a public-use monetary instrument), a contender must be open source. The Cryptocurrency Standards Association, The Bitcoin Foundation and the leading wallet vendors have always been open and eager to incorporate the best open source ideas into Bitcoin.
Even if Bitcoin were replaced by an altcoin or by “Bitcoin 2.0”, it is likely that the public would only migrate to the enhanced coin if it were tied to the original equity corpus of earned and mined coins from the Bitcoin era. That is, we all know that Satoshi may have thousands of original Bitcoins, but few among us would tolerate (a) losing all of our Bitcoin value, and (b) rewarding a blockchain wannabe who declares that his coins are worth more than the grassroots legacy of vested millions that came before.
Consider Prof Carroll’s analogy: “Who will use an acoustic string telephone when he could access a mobile phone.” A more accurate analogy is the evolution of the 32 year old AMPS phone network (the first widely deployed cell phone network). In 1983, the original phones were analogue and limited to 400 channels. Like their non-cellular predecessors, user equipment was bulky. Phones were divided into bulky components in the trunk, under the seat and a corded handset. They lacked GPS, LTE and many signaling features that we now take for granted. Yet carriers, equipment manufacturers and users were never forced to throw away equipment and start over. The network grew, adopted, and yielded incentives for incremental user-equipment upgrade.
With all due respect to the distinguished Penn State professor, John Carroll, I stand with Andreas. Bitcoin need’t relinquish the throne. It is evolving!
Bitcoin as a cryptocurrency has had its moments of strength and weakness. The technology behind bitcoins, however, is a different story. While skeptics don’t expect a lot from Bitcoin as an alternative currency because of its volatility, they do have high hopes for the technological innovation that powers it, believing that it can be further developed to create something much powerful than Bitcoin itself.
To those who know Bitcoin as a great way of transacting online, but don’t completely understand its dynamics, it’s time to get acquainted with the cryptocurrency’s mathematical wonders that make anonymous, faster, and cheaper transactions of moving funds on the internet possible.
Most of us know that Bitcoin uses the SHA-256 hashing algorithm, but hashing serves a different function and purpose from that of digital signatures. Hashing actually provides proof that a message has not been changed because running the same hash always generates similar result.
Any message, regardless of the size can go into a hash function where the algorithm breaks it down, combines the parts, and “digests” it until it makes a fixed-length outcome called “digest”. However, a good hashing algorithm possesses some critical characteristics, in which the same message always produces the same result, as mentioned above, and it only works in one direction.
This means that even the smallest change creates a completely different digest. This is called the “avalanche effect”. Also, the chances of generating the same digest from a transformed message are a tad rare. This is called “collision resistance”.
Such nature of Bitcoin’s hash function makes it impossible to change records and transactions once they have been documented. As soon as the hashes are hashed together within the blockchain, counterfeiting records of transactions is no way near possible.
Then there’s the technology of wallet software. This is where people store bitcoins and use for making transactions. The wallet system is set in which users are prohibited from spending the same units twice (double-spending) by checking new transactions against the blockchain and against other new transactions to ensure the same units are not being cited more than once.
Though this system was established to avoid fraudulent activities and has proven to be an effective one, it also became an ideal scenario for hacking attacks on a Bitcoin exchange that aim to steal bitcoins. It’s because once bitcoins are lost, they’re gone for good and there’s no way of reclaiming them, especially that cryptocurrency usage is not covered by the central government and other intermediary parties like banks. Nonetheless, it’s not totally the Bitcoin’s fault; it’s the Bitcoin exchanges’ security measures.
Quoted: “Legendary cyberculture icon (and iconoclast) R.U. Sirius and Jay Cornell have written a delicious funcyclopedia of the Singularity, transhumanism, and radical futurism, just published on January 1.” And: “The book, “Transcendence – The Disinformation Encyclopedia of Transhumanism and the Singularity,” is a collection of alphabetically-ordered short chapters about artificial intelligence, cognitive science, genomics, information technology, nanotechnology, neuroscience, space exploration, synthetic biology, robotics, and virtual worlds. Entries range from Cloning and Cyborg Feminism to Designer Babies and Memory-Editing Drugs.” And: “If you are young and don’t remember the 1980s you should know that, before Wired magazine, the cyberculture magazine Mondo 2000 edited by R.U. Sirius covered dangerous hacking, new media and cyberpunk topics such as virtual reality and smart drugs, with an anarchic and subversive slant. As it often happens the more sedate Wired, a watered-down later version of Mondo 2000, was much more successful and went mainstream.”
Quoted: “Tony Williams, the founder of the British-based legal consulting firm, said that law firms will see nearly all their process work handled by artificial intelligence robots. The robotic undertaking will revolutionize the industry, “completely upending the traditional associate leverage model.” And: “The report predicts that the artificial intelligence technology will replace all the work involving processing information, along with a wide variety of overturned policies.”
When accessing or authenticating (for example, logging into a corporate VPN or completing a credit card purchase), you are presented with a tiled screen of individual faces. I prefer a big 15×5 grid = 75 images, but Passfaces uses sequential screens of just 9 faces arranged like the number pad on an ATM.
The Experiment
dark side). There are many areas in which Bitcoin could be improved, or made more conducive to one camp or another.
