Quantum Cryptography - What Is Quantum Cryptography? How Does It Work?

Quantum cryptography makes use of unique quantum characteristics of nature to complete a cryptographic job. 

Most quantum cryptography algorithms are information theoretically safe (at least in theory), which is a very strong concept of security since it is derived only from information theory. 

Early attempts to utilize quantum characteristics for security reasons may be traced back to the 1970s, when Wiesner attempted to produce unfalsifiable bank notes. 

However, these concepts seemed to be impractical, since they required the storage of a single polarized photon for days without loss (at the time, photon polarization was the only conceived carrier of quantum information). 

Bennett and Brassard made the breakthrough in 1983, when they discovered that photons are better utilized to convey quantum information rather than to store it. 

• They might, for example, be used to convey a random secret key from a sender to a recipient, who would then be able to encrypt and decode sensitive communications using the key. 

• Bennett and Brassard released the first quantum key distribution (QKD) protocol, dubbed the BB84 protocol, shortly after. 

A QKD protocol allows two parties to create a shared secret key using an unsecured quantum channel and a public classical channel that has been authenticated. 

• Since then, a slew of new protocols have been suggested – and implemented – propelling QKD to the forefront of quantum cryptography and one of the most important applications of quantum information science. 

• Furthermore, driven by growing concerns about data security and the possibility of commercialization, quantum cryptography research has drawn the interest of a number of businesses, private organizations, and governments.

 

In reality, quantum cryptography solutions are being offered by an increasing number of businesses and startups across the globe. 

• In the long run, scientists want to build large-scale quantum networks that will allow safe communication between any subset of users in the network due to quantum entanglement. 

• In a wider sense, similar networks may be connected together to form a quantum internet, which could be used for much more than secure communication, such as safe access to distant quantum computers. 

Quantum cryptography elegantly integrates concepts and contributions from a variety of disciplines, including quantum information and quantum communication, as well as computer science and conventional encryption. 

• The interaction of these disparate disciplines leads to theoretical breakthroughs that are of wide interest and transferable to other areas of study. 

• However, since quantum cryptography, and in particular QKD, has a considerable economic appeal, ongoing research is also driven by more practical goals. 

For example, combined theoretical and practical efforts are continuously dedicated to: improving the key-generation rates, simplifying the experimental setups, and so on by focusing on an unique QKD protocol that has lately garnered a lot of attention from the scientific community and is widely regarded as the new standard for long-distance QKD in fiber. 

Twinfield (TF) QKD is a technique that enables two parties to create a secret key across vast distances using single-photon interferometric measurements in an intermediary relay. 

• In this context, we use current theoretical findings and simulations to examine practical TF-QKD implementations in depth. 

• With bipartite QKD connections becoming the norm at many research institutions and field deployments across the globe, the next major step would be to join these isolated links into quantum networks to conduct more complex multi-user activities. 

• The extension of QKD to many users using multipartite QKD, also known as quantum conference key agreement (CKA), is undoubtedly a logical application of future quantum networks. 

When a confidential communication has to be securely broadcast among a group of users, the CKA protocol is used. 

• The users share a shared secret key—the conference key—with which they may encrypt and decode the secret message when they utilize the CKA protocol. 

In this section, CKA plays a significant part. 

• We provide an understandable description of CKA's evolution from current QKD protocols to expose the reader to it. 

• We extend QKD's security architecture to incorporate CKA and concentrate on a multipartite variant of the widely used BB84 protocol. 

• We also go through some of the most recent experimental implementations of CKA protocols, with a focus on the multipartite BB84 protocol. 

• We describe a new CKA technique based on the TF-QKD operating principle, in which several users distil a conference key via single-photon interference events. 

• We demonstrate that the protocol outperforms prior CKA schemes over long distances thanks to this feature, since it uses a W-class state as its entanglement resource instead of the traditional GHZ state.

~ Jai Krishna Ponnappan

You may also want to read more about Quantum Computing here.

What Is Post-Quantum Cryptography?

Cryptography after the Quantum Era (PQC). 

In the last decade, significant developments in quantum computing have reassured the scientific community of the need to develop quantum-resistant cryptosystems. 

• Quantum computers represent a danger to conventional public-key encryption based on number theory, thus Post-Quantum Cryptography (PQC) has emerged as the preferable alternative (i.e., integer factorization or discrete logarithms). 

Cryptosystems that are safe against assaults launched on classical computers and possibly quantum computers may be designed using:

 

1. lattice-based cryptography, 
2. multivariate cryptography, 
3. hash-based cryptography schemes, 
4. isogeny-based cryptography, 
5. and code-based encryption. 

• As a result, these methods are known as PQC (Post Quantum Cryptography) algorithms. 

Cryptography methods based on lattices are easy to build and provide a solid demonstration of security. 

• The shortest vector problem (SVP), which involves estimating the minimum Euclidean length of a lattice vector for any basis, is the foundation of lattice-based encryption. 

• The worst-case quantum polynomial time to solve SVP is approximately exp(O(√ n)).  

• SVP's complexity is polynomial in n even with the processing capability of a quantum computer. 

• One of the numerous issues in the lattice family is Short Integer Solutions (SIS). 

• If the SVP is difficult in the worst situation, SIS issues are secure in the average scenario. 

The fundamental assumptions of code-based cryptography systems are that the generator matrix and random matrix are indistinguishable and that generic decoding is difficult. 

• Because they are based on a well-studied issue, these methods take a conservative approach to public key encryption/key encapsulation. 

• If the key size is decreased, this class of algorithms becomes susceptible. 

• Researchers have proposed methods for reducing key size without jeopardizing security. 

• The complexity of solving the finite field multivariate polynomial (MVP) problem inspires multivariate cryptography. 

MVP issues are NP-hard to solve. 

• MVPs are NP-complete problems if all equations are quadratic over GF. 

• Despite the fact that certain MVP-based methods have been proven to be weak, the PQC signature technique provides for competitive signature sizes. 

• The security characteristics of the underlying symmetric primitives, particularly cryptographic hash functions, are used to create hash-based digital signatures (leveraging properties of collision resistance and second pre-image resistance). 

The National Institute of Standards and Technology (NIST) stated in that it will launch a standardization project to establish quantum-resistant standards for Key Encapsulation Mechanism (KEM) and Public Key Encryption (PKE), as well as digital signatures. 

NIST specified five distinct security strengths directly linked to NIST standards in symmetric cryptography in the request for proposals: Security Level : 

1. Algorithm is at least as difficult to crack as AES (but it is less quantum resistant—Exhaustive Key Search). 
2. Algorithm is at least as difficult to crack as SHA (strong in terms of quantum resistance—Collision Search). 
3. Algorithm is at least as difficult to crack as AES (and is stronger in terms of quantum resistance—Exhaustive Key Search). 
4. Algorithm is at least as difficult to crack as SHA (very strong quantum resistance—Collision Search). 
5. Algorithm is at least as difficult to crack as AES (the strongest in terms of quantum resistance—Exhaustive Key Search). 

The NIST PQC Competition's first round began in December and received entries, from which digital signature contenders and KEM/PKE methods were selected. 

• The NIST PQC Competition's second round candidates were revealed in January: digital signature candidates and KEM/PQC schemes. 

• Just as the current work is going to print, NIST has officially announced a third cycle, which will begin in June. 

The Table below summarizes the round candidates, associated scheme, and NIST security level mapping.(Click through to zoom in)

~ Jai Krishna Ponnappan

You may also want to read more about Quantum Computing here.

Quantum Computing Keywords

We can start to focus in on qubit modalities by composing a working quantum computing vocabulary:

Table Of Contents
What Are Qubits?
What Is A Universal Quantum Computer?
What Is Quantum Annealing?
What Is Quantum Speedup?
What Is Quantum Edge?
What Is Quantum Supremacy?
What Is A Bloch Sphere?
What Is Coherence in Quantum Computing?
What Is DiVincenzo Criteria?
What Is Quantum Entanglement?
What Is Measurement In Quantum Computing?
What Are Quantum Dots?
What Is Quantum Error Correction?
What Is Quantum Indeterminacy?
What Is Quantum Tunneling?
What Is Superposition?
What Is Teleportation In Quantum Computing?
What Is A Topological Quantum Computer?

What Are Qubits?

The quantum equivalent of conventional digital bits are qubits (quantum bits). 

• The qubits are in a state of superposition and operate on quantum mechanics principles. 

• To alter the state of the qubits, we must use quantum mechanics concepts. 

• We can measure the state of the qubits at the conclusion of the computation by projecting them into conventional digital bits. 

What Is A Universal Quantum Computer?

A Quantum Turing Machine, also known as a Universal Quantum Computer, is an abstract machine that is used to simulate the effects of a quantum computer. 

• Any quantum algorithm may be described formally as a particular quantum Turing Machine, similar to the conventional Turing Machine. 

Quantum states defined in Hilbert space are used to represent internal states. 

• In Hilbert space, the transition function is a collection of unitary matrices. 

What Is Quantum Annealing?

Quantum Fluctuations are used to discover a heuristic method that finds a global minimum from a limited collection of candidate solutions. 

• Quantum Annealing may be used to tackle combinatorial optimization problems having a discrete search space with multiple local minima, such as the traveling salesman problem. 

• The system begins with the quantum parallelism superposition of all possible states and evolves using the time-dependent Schrodinger equation. 

• The amplitudes of all states may be altered by changing the transverse field (a magnetic field perpendicular to the axis of the qubit), resulting in Quantum Tunneling between them. 

The aim is to maintain the system as near to the Hamiltonian's ground state as possible. 

• The system achieves its ground state when the transverse field is eventually switched off, which corresponds to the solution of the optimization issue. 

• D-Wave Systems exhibited the first Quantum Annealer in 2011. 

What Is Quantum Speedup?

This is the best-case situation, in which no classical algorithm can outperform a quantum algorithm. 

• There are a few quantum algorithms that have a polynomial speedup in addition to factorization and discrete logarithms. 

• Grover's algorithm is one such algorithm. 

There have been reports on simulation methods for physical processes in quantum chemistry and solid-state physics. 

• The main ideal problem in polynomial time and an approximation method for Jones polynomial with a polynomial speedup and a solution to Pells' equation have been presented. 

• This area is changing. 

What Is Quantum Edge?

Quantum computers have a computational advantage. 

• The idea that quantum computers can execute certain calculations more quickly than traditional computers. 

What Is Quantum Supremacy? 

Quantum computers' prospective capacity to tackle issues that conventional computers can't. 

• Decoherence is the process by which the quantum information in a qubit is lost over time as a result of interactions with the environment. 

• Quantum Volume is a practical method to track and compare progress toward lower system-wide gate error rates for quantum computing and error correction operations in the near future. 

• It's a single-number metric that a concrete protocol can measure with a quantum computer of modest size n <=50 in the near future.

What Is A Bloch Sphere?

The Bloch sphere, named after scientist Felix Bloch, is a geometrical representation of the pure state space of a two-level quantum mechanical system (qubit) in quantum mechanics. 

• Antipodal points correspond to a pair of mutually orthogonal state vectors on the Bloch sphere, which is a unit sphere. 

The Bloch Sphere's interpretation is as follows: 

• The poles represent classical bits, and the notation |0 and |1 is used to denote them. 

• Unlike conventional bit representation, where these are the only conceivable states, quantum bits span the whole sphere. 

• As a result, quantum bits contain a lot more information, as shown by the Bloch sphere. 

• When a qubit is measured, one of the two poles collapses. 

Which of the two poles collapses depends on which direction the arrow in the Bloch representation points: 

• if the arrow is closer to the north pole, there is a greater chance of collapsing to that pole; similarly, 
• if the arrow is closer to the south pole, there is a greater chance of collapsing to that pole. 

This adds the concept of probability to the Bloch sphere: 

• the angle of the arrow with the vertical axes correlates to that probability. 

• If the arrow points to the equator, each pole has a 50/50 probability of collapsing.

What Is Coherence in Quantum Computing?

A qubit's coherence is defined as its capacity to sustain superposition across time. 

• It is therefore the lack of "decoherence," which is defined as any process that collapses a quantum state into a classical one, such as contact with the environment.

What Is  DiVincenzo Criteria?

The DiVincenzo criteria are a set of requirements for building a quantum computer that were originally suggested by theoretical physicist David P. DiVincenzo in his article "The Physical Implementation of Quantum Computation" in 2000. 

The DiVincenzo criteria are a collection of 5+2 requirements that must be met by an experimental setup in order to effectively execute quantum algorithms like Grover's search algorithm or Shor factorization. 

To perform quantum communication, such as that utilized in quantum key distribution, the two additional requirements are required.

1 – A physically scalable system with well-defined qubits.

2 – The ability to set the qubits' states to a simple fiducial state.

3 – Long decoherence periods that are relevant.

4 – A set of quantum gates that is “universal.”

5 – A measuring capability unique to qubits.

6 — Interconversion of stationary and flying qubits.

7 – The capacity to reliably transfer flying qubits between two points.

What Is Quantum Entanglement?

Quantum entanglement is a unique relationship that exists between two qubits. 

• Entanglement may be created in a variety of ways. 

• One method is to entangle two qubits by bringing them close together, performing an operation on them, and then moving them apart again. 

• You may move them arbitrarily far away from each other after they're entangled, and they'll stay intertwined. 

The results of measurements on these qubits will reflect this entanglement. 

• When measured, these qubits will always provide a random result of zero or one, regardless of how far apart they are. 

The first characteristic of entanglement is that it cannot be shared, which allows all of the applications that are derived from it to be created. 

• If two qubits are maximally entangled, no other person in the universe may share their entanglement. 

• The monogamy of entanglement is the name given to this feature.

Maximum coordination is the second characteristic of entanglement that gives it its strength. 

• When the qubits are measured, this characteristic is shown. 

• When two entangled qubits are measured in the same basis, no matter how far apart they are, the result is always the same. 

• This result is not predetermined; rather, it is entirely random and determined at the time of measurement.

What Is Measurement In Quantum Computing?

The act of seeing a quantum state is known as measurement. 

• This observation will provide traditional data, such as a bit. 

• It's essential to remember that the quantum state will change as a result of this measurement procedure. 

If the state is in superposition, for example, this measurement will cause it to ‘collapse' into a classical state: zero or one. 

• This process of collapsing occurs at random. 

• There is no way of knowing what the result will be until the measurement is completed. 

• However, the chance of each result may be calculated. 

This probability is a prediction about the quantum state that we can test by preparing it many times, measuring it, and calculating the percentage of each result.

What Are Quantum Dots?

Quantum dots may be thought of as "manufactured atoms." 

• They are semiconductor nanocrystals in which an electron-hole pair may be trapped. 

• Because the nanoscale size is equivalent to the wavelength of light, the electron may occupy distinct energy levels, exactly as in an atom. 

• The dots may be encased in a photonic crystal cavity and probed with laser light.

What Is Quantum Error Correction?

Quantum computers are always in touch with the outside world. This environment has the potential to disrupt the system's computational state, resulting in data loss. 

• Quantum error correction compensates for this loss by distributing the system's computational state over multiple qubits in an entangled state. 

• Outside classical observers may detect and correct perturbations using this entanglement without having to see the computational state directly, which would collapse it.

What Is Quantum Indeterminacy?

The basic condition of existence, backed up by all empirical evidence, in which an isolated quantum system, like as a free electron, does not have fixed characteristics until those attributes are seen in experiments intended to quantify them. 

• That is, unless those characteristics are measured, a particle does not have a particular mass, location, velocity, or spin. 

• Indeed, the particle does not exist until it is seen in a strict sense.

What Is Quantum Tunneling?

Due to the wave-like nature of particles, quantum tunneling is a quantum mechanical phenomenon in which particles have a limited chance of overcoming an energy barrier or transiting through an energy state usually prohibited by classical physics. 

• A particle's probability wave reflects the likelihood of locating the particle in a certain place, and there is a limited chance that the particle is on the opposite side of the barrier.

What Is Superposition?

Quantum physics' basic premise is superposition. 

• It asserts that quantum states, like waves in classical physics, may be joined together – superposed – to produce a new valid quantum state, and that every quantum state can be seen as a linear combination, a sum of other unique quantum states.

What Is Teleportation In Quantum Computing?

Quantum teleportation is a technique that uses entanglement to transmit qubits. 

• The following is how teleportation works: 

• Initially, Alice and Bob must create an entangled pair of qubits between them. 

• Alice next conducts a measurement on the qubit she wishes to transmit as well as the qubit that is entangled with Bob's qubit. 

• This measurement compresses the qubits and breaks the entanglement, but it also provides her with two classical outcomes in the form of two classical bits. 

• Alice transmits these two traditional bits to Bob over the traditional Internet. 

• Bob next applies to his qubit a rectification operation that is based on these two classical bits. 

• As a result, he is able to reclaim the qubit that was previously in Alice's control. 

It's worth noting that we've now sent a qubit without really utilizing a physical carrier capable of doing so. 

To accomplish this, you'll need entanglement, of course. 

It's also worth noting that quantum teleportation doesn't allow for communication faster than the speed of light. 

• This is because Bob will not be able to make sense of the qubit she has in her hands until he receives the classical measurement results from Alice. 

• The transmission of these traditional measurement results must take a certain length of time. 

• This time is also constrained by the speed of light.

What Is A Topological Quantum Computer?

A topological quantum computer is a theoretical quantum computer that uses anyons, which are two-dimensional quasiparticles whose world lines intersect to create braided in a three-dimensional spacetime (i.e., one temporal plus two spatial dimensions). 

• The logic gates that make up the computer are formed by these strands. 

• The benefit of utilizing quantum braiding over trapped quantum particles in a quantum computer is that the former is considerably more stable. 

• Small, cumulative perturbations may cause quantum states to decohere and create mistakes in computations, but they have no effect on the topological characteristics of the braiding. 

• This is comparable to the work needed to cut a string and reconnect the ends to create a new braid, rather than a ball (representing an ordinary quantum particle in four-dimensional spacetime) colliding with a wall. 

In 1997, Alexei Kitaev suggested topological quantum computing.

~ Jai Krishna Ponnappan

You may also want to read more about Quantum Computing here.

What Is A QPU?

What is a Quantum Processing Unit (QPU)? 

Despite its widespread use, the phrase "quantum computer" may be misleading. 

It conjures up thoughts of a whole new and alien kind of computer, one that replaces all current computing software with a future alternative. 

• This is a widespread, though massive, misunderstanding at the time of writing. 
• The potential of quantum computers comes from its capacity to significantly expand the types of problems that are tractable inside computing, rather than being a traditional computer killer. 
• There are significant computational problems that a quantum computer can readily solve, but that would be impossible to solve on any conventional computing device we could ever hope to construct. 

But, importantly, these sorts of speedups have only been observed for a few issues, and although more are expected to be discovered, it's very doubtful that doing all calculations on a quantum computer would ever make sense. 

For the vast majority of activities that use your laptop's clock cycles, a quantum computer is no better. 

In other words, a quantum computer is actually a co-processor from the standpoint of the programmer. 

• Previously, computers utilized a variety of coprocessors, each with its own set of capabilities, such as floating-point arithmetic, signal processing, and real-time graphics. 

• With this in mind, we'll refer to the device on which our code samples run as a QPU (Quantum Processing Unit). 

This, we believe, emphasizes the critical context in which quantum computing should be considered. 

A quantum processing unit (QPU), sometimes known as a quantum chip, is a physical (fabricated) device with a network of linked qubits. 

• It's the cornerstone of a complete quantum computer, which also comprises the QPU's housing environment, control circuits, and a slew of other components.

Programming for a QPU

Like other co-processors like the GPU (Graphics Processing Unit), QPU programming entails creating code that will mainly execute on a regular computer's CPU (Central Processing Unit). 

• The CPU only sends QPU coprocessor instructions to start tasks that are appropriate for its capabilities. 

• Fortunately (and excitingly), a few prototype QPUs are already accessible and may be accessed through the cloud as of this writing. 

• Furthermore, conventional computer gear may be used to mimic the behavior of a QPU for simpler tasks. 

Although emulating bigger QPU programs is impractical, it is a handy method to learn how to operate a real QPU for smaller code snippets. 

• Even when more complex QPUs become available, the fundamental QPU code examples will remain both useful and instructive. 

• There are a plethora of QPU simulators, libraries, and systems to choose from.

Quantum Processing Units (QPU) Make Quantum Computing Possible.

A quantum processing unit (QPU) is a physical or virtual processor with a large number of linked qubits that may be used to calculate quantum algorithms. 

• A quantum computer or quantum simulator would not be complete without it. 

• Quantum devices are still in their infancy, and not all of them are capable of running all Q#  programs. 

• As a result, while creating programs for various targets, you must keep certain constraints in mind. 

• Quantum mechanics, the study of atomic structure and function, is used to create a computer architecture. 

Quantum computing is a world apart from traditional computing ("classical computing"). 

• It can only answer a limited number of issues, all of which are based on mathematics and expressed as equations. 

• Quantum computer processing imitates nature at the atomic level, and one of its most promising applications is the investigation of molecule interactions in order to unravel nature's secrets. 

At Oxford University and IBM's Almaden Research Center in 1998, the first quantum computers were demonstrated. 

• There were around a hundred functional quantum computers across the globe by 2020. 

• Due to the exorbitant expense of creating and maintaining quantum computers, quantum computing will most likely be delivered as a cloud service rather than as hardware for enterprises to purchase. We'll have to wait and see. 

Quantum coprocessor and quantum cloud are two terms for the same thing. 

Because data rise at such a rapid rate, even the fastest supercomputers face a slew of issues. 

• Consider the classic traveling salesman dilemma, which entails determining the most cost-effective round journey between locations. 

• The first stage is to calculate all feasible routes, which yields a 63-digit number if the journey involves 50 cities. 

• Whereas traditional computers may take days or even months to tackle similar issues, quantum computers are projected to respond in seconds or minutes. 

• Quantum teleportation, binary values, rice, and the chessboard legend are all examples of quantum supremacy. 

Superposition and Entanglement of Qubits. 

Quantum computing relies on the "qubit," or quantum bit, which is made up of one or more electrons and may be designed in a variety of ways. 

• The situation that permits a qubit to be in several states at the same time is known as quantum superposition (see qubit). 

• Entanglement is a trait that enables one particle to communicate with another across a long distance. 

• The two major kinds of quantum computer designs are gate model and quantum annealing. 

 

Gate Model QC

 

"Quality Control Model" : 

Quantum computers based on the gate model have gates that are similar in principle to classical computers but have significantly different logic and design. 

• Google, IBM, Intel, and Rigetti are among the businesses working on gate model machines, each with its own qubit architecture. 

• Microwave pulses are used to train the qubits in the quantum device. 

• The QC chip does digital-to-analog and analog-to-digital conversion. 

IBM's Q Experience on the Cloud

• In 2016, IBM released a cloud-based 5-qubit gate model quantum computer to enable scientists to experiment with gate model programming. 

• The open source Qiskit development kit, as well as a second machine with 16 qubits, were added a year later. 

• A collection of instructional resources is available as part of the IBM Q Experience. 

• IBM Q Gate Model

Superconducting materials

• Superconducting materials, like those employed in the D-Wave computer, must be stored at subzero temperatures, and both photographs show the coverings removed to reveal the quantum chip at the bottom. 

• Intel's Tangle Lake gate model quantum processor, featuring a novel design of single-electron transistors linked together, was introduced in 2018. 

• At CES 2018, Intel CEO Brian Krzanich demonstrated the processor. 

D-Wave Systems

D-Wave Systems in Canada is the only company that provides a "quantum annealing" computer. 

• D-Wave computers are massive, chilled computers with up to 2,000 qubits that are utilized for optimization tasks including scheduling, financial analysis, and medical research. 

• To solve an issue, annealing is used to identify the best path or the most efficient combination of parameters. 

D-Wave Chips have 5,000 qubits in their newest quantum annealing processor. 

• A cooling mechanism is required, much as it is for gate type quantum computers. 

• It becomes colder all the way down to minus 459 degrees Fahrenheit using liquid nitrogen and liquid helium stages from top to bottom. 

Algorithms for Quantum Computing. 

Because new algorithms impact the construction of the next generation of quantum architecture, the algorithms for addressing real-world issues must be devised first. 

• Both the gate model and the annealing processes have challenges to overcome. 

• However, experts anticipate that quantum computing will become commonplace in the near future. 

State of Quantum Computing

Quantum computers are projected to eventually factor large numbers and break cryptographic secrets in a couple of seconds. 

• It is just a matter of time, according to scientists, until this becomes a reality. 

• When it occurs, it will have grave consequences since every encrypted transaction, as well as every current cryptocurrency system, will be exposed to hackers. 

• Quantum-safe approaches, on the other hand, are being developed. Quantum secure is one example of this. 

The United States, Canada, Germany, France, the United Kingdom, the Netherlands, Russia, China, South Korea, and Japan are the nations that are studying and investing in quantum computing as of 2020. 

The field of quantum computing is still in its infancy. 

When an eight-ton UNIVAC I in the 1950s developed into a chip decades later, it begs the question of what quantum computers would look like in 50 years.

~ Jai Krishna Ponnappan

You may also want to read more about Quantum Computing here.