Monthly Archives: July 2021

Feature Do the laws of physics trump mathematical complexity, or is Quantum Key Distribution (QKD) nothing more than 21st-century enterprise encryption snake oil? The number of QKD news headlines that have included unhackable, uncrackable or unbreakable could certainly lead you towards the former conclusion.

However, we at The Reg are unrelenting sceptics for our sins and take all such claims with a bulk-buy bag of Saxa. What this correspondent is not, however, is a physicist nor a mathematician, let alone a quantum cryptography expert. Thankfully, I know several people who are, so I asked them the difficult questions. Here's how those conversations went.

I can tell you what QKD isn't, and that's quantum cryptography. Instead, as the name suggests, it's just the part that deals with the exchange of encryption keys.

As defined by the creators of the first Quantum key distribution (QKD) protocol, (Bennett and Brassard, 1984) it is a method to solve the problem of the need to distribute secret keys among distant Alice and Bobs in order for cryptography to work. The way QKD solves this problem is by using quantum communication. "It relies on the fact that any attempt of an adversary to wiretap the communication would, by the laws of quantum mechanics, inevitably introduce disturbances which can be detected."

Quantum security expert, mathematician and security researcher Dr Mark Carney explains there "are a few fundamental requirements for QKD to work between Alice (A) and Bob (B), these being a quantum key exchange protocol to guarantee the key exchange has a level of security, a quantum and classical channel between A and B, and the relevant hardware and control software for A and B to enact the protocol we started with."

If you are the diagrammatical type, there's a nifty if nerdy explanatory one here.

It's kind of a given that, in and of themselves, quantum key exchange protocols are primarily very secure, as Dr Carney says most are derived from either BB84 (said QKD protocol of Bennett and Brassard, 1984) or E91 (Eckert, 1991) and sometimes a mixture of the two.

"They've had a lot of scrutiny, but they are generally considered to be solid protocols," Dr Carney says, "and when you see people claiming that 'quantum key exchange is totally secure and unhackable' there are a few things that are meant: that the key length is good (at least 256 bits), the protocol can detect someone eavesdropping on the quantum channel and the entropy of the system gives unpredictable keys, and the use of quantum states to encode these means they are tamper-evident."

So, if the protocol is accepted as secure, where do the snake oil claims enter the equation? According to Dr Carney, it's in the implementation where things start to get very sticky.

"We all know that hardware, firmware, and software have bugs even the most well researched, well assessed, widely hacked pieces of tech such as the smartphone regularly has bug updates, security fixes, and emergency patches. Bug-free code is hard, and it shouldn't be considered that the control systems for QKD are any different," Carney insists.

In other words, it's all well and good having a perfected quantum protocol, but if someone can do memory analysis on A or B's systems, then your "super secure" key can get pwned. "It's monumentally naive in my view that the companies producing QKD tech don't take this head on," Dr Carney concludes. "Hiding behind 'magic quantum woo-woo security' is only going to go so far before people start realising."

Professor Rob Young, director of the Quantum Technology Centre at Lancaster University, agrees that there is a gap between an ideal QKD implementation and a real system, as putting the theory into practice isn't easy without making compromises.

QKD connections can be blocked using a DDoS attack as simple as using a pneumatic drill in the vicinity of the cable

"When you generate the states to send from the transmitter," he explains, "errors are made, and detecting them at the receiver efficiently is challenging. Security proofs typically rely on a long list of often unmet assumptions in the real world."

Then there are the hardware limitations, with most commercially implemented QKD systems using a discrete-state protocol sending single photons down low-loss fibres. "Photons can travel a surprising distance before being absorbed, but it means that the data exchange rate falls off exponentially with distance," Young says.

"Nodes in networks need to be trusted currently, as we can't practically relay or switch quantum channels without trusting the nodes. Solutions to these problems are in development, but they could be years away from commercial implementation."

This lack of quantum repeaters is a red flag, according to Duncan Jones, head of Quantum Cybersecurity at Cambridge Quantum, who warns that "trusted repeaters" are not the same thing. "In most cases this simply means a trusted box which reads the key material from one fibre cable and re-transmits it down another. This is not a quantum-safe approach and negates the security benefits of QKD."

Then there's the motorway junction conundrum. Over to Andersen Cheng, CEO at Post-Quantum, to explain. Cheng points to problems such as QKD only telling you that a person-in-the-middle attack has happened, with photons disturbed because of the interception, but not where that attack is taking place or how many attacks are happening.

"If someone is going to put a tap along your 150km high-grade clear fibre-optic cable, how are you going to locate and weed out those taps quickly?" Cheng asks.

What if an attacker locates your cable grid and cuts a cable off? Where is the contingency for redundancy to ensure no disruption? This is where the motorway junction conundrum comes in.

"QKD is like two junctions of a motorway," Cheng explains. "You know car accidents are happening because the road surface is being attacked, but you do not know how many accidents have happened or where or who the culprit is, so you cannot go and kick the offenders out and patch up the road surface."

This all comes to the fore when Anderson insists: "QKD connections can be blocked using a DDoS attack as simple as using a pneumatic drill in the vicinity of the cable."

Sally Epstein, head of Strategic Technology at Cambridge Consultants, throws a couple of pertinent questions into the "ask any QKD vendor" ring.

Quantum-safe cryptography, coupled with verifiable quantum key generation, is an excellent approach to the same problem and works perfectly today

"1. Supply chain: There is a much greater potential for well-funded bad actors to get into the supply chain. How do they manage their supply chain security?

"2. Human fallibility: There are almost certainly exploitable weaknesses in the control software, optical sub-assemblies, electronic, firmware, etc. What penetration testing has the supplier conducted in terms of software and hardware?"

Professor Young thinks that QKD currently offers little return on investment for your average enterprise. "QKD can distribute keys with provable security metrics, but current systems are expensive, slow and difficult to implement," he says.

As has already been pointed out, security proofs are generally based on ideal cases without taking the actual physical implementation into account. This, Young says, "troubles the central premise of using QKD in the first place."

However, he doesn't think that the limitations are fundamental and sees an exciting future for the technology.

Because QKD technology is still maturing, and keys can only be sent across relatively short distances using dedicated fibre-optic cables, Jones argues that "only the biggest enterprises and telcos should be spending any money on researching this technology today."

Not least, he says, because the problems QKD solves are equally well addressed through different means. "Quantum-safe cryptography, coupled with verifiable quantum key generation, is an excellent approach to the same problem and works perfectly today," Jones concludes.

Professor Andrew Lord, head of Optical Network Research at BT, has a less pessimistic outlook.

"Our trial with NCC in Bristol illustrates a client with a need to transmit data which should remain secure for many years into the future," Lord told The Reg. "QKD is attractive here because it provides security against the 'tap now, decrypt later' risk, where data could be stored and decrypted when a quantum computer becomes available."

The UK's National Cyber Security Centre (NCSC) has gone on the record to state it does not endorse the use of QKD for any government or military application, and the National Security Agency (NSA) in the US has reached the same conclusion.

Jones of Cambridge Quantum says he completely agrees with the NCSC/NSA perspectives because the "first generation of quantum security technologies has failed to deliver tangible benefits for commercial or government applications."

Young goes further: "Both NCSC and NSA echo the views of all serious cryptographers with regards to QKD, and I am in complete agreement with them."

So what needs to change to make QKD solutions relevant to enterprises in the real world? Lord admits that the specialised hardware requirements of QKD does mean it won't be the best solution for all use cases, but foresees "photonic-chip based QKD ultimately bringing the price down to a point where it can be integrated into standard optical transmission equipment."

Dr Carney adds: "In closing, all this leaves us with the biggest misunderstanding about QKD vs classical key exchange; in classical key exchange the mathematics that makes Elliptic Curve Diffie-Hellman Ephemeral (ECDHE) or your favourite Post-Quantum Cryptography (PQC) key exchange secure is distinct and independent of the physical channel (the classical channel) that is being used for the protocol.

"On a QKD system, the mathematics is in some way intrinsically, and necessarily, linked to the actual physicality of the system. This situation is unavoidable, and we would do well to design for and around it."

More:

Quantum Key Distribution: Is it as secure as claimed and what can it offer the enterprise? - The Register

Most people recognize that they have something that can be called a worldview, even though few would attempt to define it. Anyones worldview contains all the perceptions and shared ideas that allow us to assume we have a stable idea of how our physical environment supports us. It is an important part of everyones culture. But a worldview is more comprehensive than what we call culture, which tends to be more of a group view than a worldview. Our worldview and culture always find a way of living together, but they remain distinct.

Most of the main features of our worldview escape our critical attention. Because everyone seems to agree, we simply assume they are real. But what if they are not? Peter Evans, in the title of an article in The Conversation, asks the question, Is reality a game of quantum mirrors? He also suggests that science has actually come to that conclusion.

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In his book Helgoland, the Italian physicist Carlo Rovelli explains that our inherited assumptions about the world may have misled an entire civilization. In todays consumer culture that focuses on objects and the value we attribute to them this could have radical implications. Evans clarifies the terms of the debate: Expecting objects to have their own independent existence independent of us, and any other objects is actually a deep-seated assumption we make about the world.

Evans agrees with Rovelli that the object-oriented worldview we have inherited from Europes four-century-old scientific and industrial revolutions needs reassessment. He supports Rovellis thesis that quantum theory the physical theory that describes the universe at the smallest scales almost certainly shows this worldview to be false. Instead, Rovelli argues we should adopt a relational worldview.

Todays Daily Devils Dictionary definition:

Relational worldview:

A mindset which recognizes that things have no identity or measurable value without other things, as opposed to an object-oriented mindset that isolates all things to put a price tag on them

Individuals have a worldview, but so do civilizations. Most individuals worldview shares a preponderant number of common features with their civilizational worldview. But every individuals worldview varies in some respects with regard to societys worldview. This is especially true in the modern civilizations that value individualism and have come to dominate in the West.

The features that diverge from the dominant worldview give us a sense of our own identity, either as a unique individual or even as a member of a group. We tend to respect commonly shared assumptions and beliefs while at the same time needing to affirm the subtle features that make our worldview distinct. Most people nevertheless remain unaware of what distinguishes their civilizations worldview from other real and possible worldviews. In that sense, worldviews can become tyrannical.

Rovelli believes that the fundamental understanding scientists have acquired about the undeniable laws of quantum mechanics indicates that one of the key features of our inherited and shared worldview our belief in the reality of objects is mistaken. As Evans points out, He claims the objects of quantum theory, such as a photon, electron, or other fundamental particle, are nothing more than the properties they exhibit when interacting with in relation to other objects. In other words, without the interaction, nothing can be said to exist.

The corollary of this is that there is no underlying individual substance that has the properties. This contradicts our current worldview that has imposed the idea that we live in a world of substances, each of which has properties. It turns out that properties are the only things that are real. They combine to create the illusion of substance.

Rovelli proposes moving away from the culture that divides the world into an indefinite number of substances to which we attribute properties and replacing it with the understanding that the form of anything we perceive is entirely the effect of a relationship. As Evans expresses it, according to the relational interpretation, the state of any system is always in relation to some other system. In this reading of reality, nothing can be understood or even exist outside of its context. It also means that contexts have context. These are two radically different ways of looking at the world.

There is an interesting parallel with the research of contemporary anthropologists who have focused on the comparative analysis of cultures. Just as Rovelli opposes an object-oriented worldview to a relation-oriented worldview, the anthropologists contrast relationship-oriented cultures and task-oriented cultures. US culture is usually cited as an extreme example of a task-oriented culture. More than in any other culture and in stark contrast to most Asian, African and Latin American cultures Americans view social interaction as a pretext for accomplishing something. They always have an object to achieve. Relationships are acknowledged primarily as contexts that permit transactions or the transfer of property rather than as the invisible but powerfully organized foundation of social reality.

Reviewing Rovellis book for The Guardian, Manjit Kumar sums up Rovellis thesis in these terms: The world that we observe is continuously interacting; it is better understood as a web of interactions and relations rather than objects. Most cultures in human history have made similar assumptions about society itself, emphasizing the reality of relationships.

Todays Americanized worldview serves the useful purpose of justifying capitalistic notions of ownership and attribution of value, an industrial organization that treats people who produce and consume as objects, and the consumer society itself made up of people purchasing objects. It came into being over the past four centuries in Western Europe and North America. It now dominates what education and the media have conditioned us to think about the world. Contemporary physics and cross-cultural anthropology stand as exceptions that embrace relationships as the foundation of everything. Philosophy, economics and political science clearly have not caught up.

The interesting parallel between the findings of quantum physics and cross-cultural anthropology reveals something about what would be implied if the paradigm shift Rovelli recommends were to occur. It would imply our civilizations taking on board the new understanding of physical reality and applying the lessons to social organization itself.

The task-oriented, fundamentally utilitarian culture that emerged in the English-speaking world during the industrial revolution became massively dominant across the globe in the 20th century. Its global victory can be attributed to the emergence of mass media and the expanding wave of soft power that accompanied the hard power of the US military and the almighty dollar. Today, all our institutions reflect an implicit political worldview that sees the nation-state as the only legally recognized source of social legitimacy.

These institutions, and their rules and practices, require thinking of the human environments as enclosed zones that contain a finite collection of substances (economic resources) endowed with properties, one of those properties being commercial value. It has inevitably produced the widely accepted, though often disparaged, truism: Everything has a price.

Changing an entire populations worldview would be a monumental task, but it has occurred in the past. Rovelli is an optimist. His optimism stems from his belief which is widely shared in the modern Western worldview that science has a mission of communicating the truth about the world we live in and that, once that truth is unambiguously established, the logical thing to do would be to modify the civilizations worldview. But Rovellis thesis contradicts the culture that embraces it, which means that resistance will be fierce. We now tend to think of truth itself as a quantifiable object, as when we say things like, How much truth is anyone willing to accept?

In the 16th and 17th centuries in Europe, a radical shift took place in the dominant worldview. It led to the scientific and industrial revolutions. We traditionally represent it as a shift from superstition to science. But it was also a shift from a relationship-based worldview to a mechanical, object-oriented one. Feudalism itself was a system of interacting relationships, as Thomas Piketty insisted in his book Capital and Ideology. Now science has led us to a point at which the scientific revolution may appear as a denial of the true understanding of science. In his book, Rovelli reveals that he himself looks beyond the various Western worldviews to Eastern philosophy, that of the second-century Indian philosopher Nagarjuna, for inspiration.

*[In the age of Oscar Wilde and Mark Twain, another American wit, the journalist Ambrose Bierce, produced a series of satirical definitions of commonly used terms, throwing light on their hidden meanings in real discourse. Bierce eventually collected and published them as a book, The Devils Dictionary, in 1911. We have shamelessly appropriated his title in the interest of continuing his wholesome pedagogical effort to enlighten generations of readers of the news. Read more of The Daily Devils Dictionary on Fair Observer.]

The views expressed in this article are the authors own and do not necessarily reflect Fair Observers editorial policy.

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A Quantum Critique of the Western Worldview - Fair Observer

Issued on: 05/07/2021 - 15:05

Researchers at theFrench Alternative Energies and Atomic Energy Commission(CEA) in Grenoble are confident of reaching a key milestone at the end of this year in their quest to build a quantum computer.

Maud Vinet and Silvano De Franceschi from the CEA along with Tristan Meunier of CNRSare leading a multidisciplinary teamof around 50 scientists and engineers to build a silicon based quantum machine, the first critical step of which would be to operate a network of two qubits in the coming months.

How quantum computing works

Qubits are the units of information in quantum computing. They are the quantum equivalent of bits. Unlike classical computing where bits can exist as either 0 or 1, in quantum systems they possess both values at the same time. This property is called superposition.

The other key quantum property is called entanglement. It refers to the almost instantaneous effect two qubits have on each other even at a distance after having been initially coupled. Entanglement and superposition give quantum computers their phenomenal calculating power.

But keeping qubits entangled is a big challenge. It is subject to interference from the environment. Any disturbances, whether thermal, electrical or mechanical, can cause errors, De Franceschi says.

One way to limit the errors caused by these factors is to operate the qubits in a deep freeze mode.

When qubits are cooled down to sufficiently low temperature, typically below a few degrees Kelvin, they are no longer susceptible to undesirable thermal excitations and their coherence can be preserved, Vinet says.

Though the system to cool qubits uses the similar principle as that of a household refrigerator, it is much bigger and way more complex.

The CEA has several cryostats that use helium to achieve a temperature between 15 millikelvin to 1 Kelvin.

That corresponds to 272 degrees below waters freezing point. Besides the above-mentioned cryostats, the CEA also boasts of a cryogenic prober that can carry out automatic measurements of 300 mm silicon wafers below 2 Kelvin or minus 271 degree Celsius. There are only two such machines in the world.

The French approach

There are four major approaches to fabricate the qubits: photons, trapped ions, superconductors and semiconductors like silicon.

Vinet and De Franceschi have adopted the last approach which involves the use of the magnetic moment of an electron in silicon to create the two different states of the qubit. They have chosen silicon even though it seems to be lagging behind the others in terms of the number of interacting qubits in a network.

The other three approaches seem to have made more progress. But we are sticking with silicon. Thats because building workable quantum computers is not a short term race. It doesnt matter where you stand today. What matters more is the growth potential for the future, De Franceschi told RFI.

According to Vinet, in order to build a practical quantum computer, scalability will be the key. In this regard, theres no better candidate than silicon, which is central to the semiconductor industry. With silicon we can fabricate millions or even billions of qubits that can be assembled in a relatively compact system. Its also convenient for control electronics.

Moreover, according to De Franceschi, when it comes to performance, the silicon qubits are on par with the other platforms in terms of fidelity and speed of operations. De Franceschi contends that some of the other approaches may be appropriate but they may not be equally suitable when it comes to effective, massive and easy manufacturing.

You need to consider how good you can scale up and handle the controlling of qubits once the processor size grows. There are other problems such as possible interference when you are manipulating qubits. The successful approach will be the one that copes the best with all these issues, he says.

Researchers at CEA have a unique advantage as both the physics and the engineering requirements necessary to build a quantum computer are available under the same roof.

While De Franceschi and his team are engaged in perfecting the fabrication and interactions between qubits, Vinet and his group are working in parallel to make qubits truly scalable and to build the other components of a quantum computer.

What we are trying to do here is build a full stack quantum computer. We are developing the quantum chip, control electronics, implementation of the quantum algorithm as well as an interface that translates the algorithm into electrical signals, Vinet says.

Quantum appeal

Quantum computers have elicited huge interest from not just research labs but also IT giants, start ups and governments. In January 2021, French President Emmanuel Macron announced a 1.8 billion euro Quantum Plan initiative for supporting research and development of quantum technologies.

The enormous appeal of quantum computing lies in its promise to easily outperform even the worlds most powerful supercomputers on certain types of calculations.

They are expected to solve complex problems such as protein simulations, calculating air flow on aircraft, finding new materials such as possibly room temperature superconductors, Vinet says, adding researchers still dont know how powerful these machines will turn out to be.

More:

French researchers on the verge of quantum computing milestone - RFI English