Cornify Quantum Computing and Cryptography

Thursday, May 7, 2015

Blog Post Five - Politics and Policy Intersection

For my final blog post, I want explain how politics, policy, and cultural phenomena intersects with research done in Quantum Computing and Quantum Cryptography. Most of my blog thus far has exclusively described the mechanisms of the quantum computer and how these machines exploit the use of qubits to open a new realm of possibilities for the way we can compute data. I have not gone nearly as in depth in my blog describing how these quantum mechanisms leap bounds for securing data and networks. This blog post will focus on the cryptographic applications of quantum computing, and how public policy and opinion helps guide and motivate research done in this specific cryptographic discipline.

Cryptography, as I described in my very first introductory blog post, is effectively a method to distort and abstract data so that it may not be interpreted correctly by malicious users, but then return the data to it's original legible state for authorized users of any given system. The part of cryptography where we secure and abstract data is known as "encryption", and the part where we take the encrypted data and return it to its original state is known as "decryption". Essentially, when a user wishes to create a secure document, they first write it as they logically intend. Then, cryptography steps in and takes the data, and distorts it so that no human being can interpret what the user's document contains. The purpose of doing this is so that if somebody steals or intercepts the data which the user wished to keep secure, it is completely useless to the thief. The data is stored this way on a local database or online data store of some flavor. The moment that an authorized user of the system wishes to access the document through legitimate means, the cryptographic system will perform a decryption algorithm on the data, so they document can be accurately interpreted. This can be thought of as a lock and key, where encryption is the lock and decryption is the key. Below I have included a graphic to demonstrate this:
Image credit: Link

Another method of encryption separates data in multiple abstract data sections, but is only interpreted accurately when all sections of data join. Usually this is fragmented into hundreds of thousands of parts, but the follow image below illustrates the concept with only two sections of data. 
Image credit: Link

Now that I have refreshed and added to our understand of some basic cryptographic concepts, I would like to focus on public policy and politics that revolve around the concepts of cryptography. Realize that the concepts I am discussing apply to both traditional cryptography AND quantum cryptography. The quantum concepts intertwined with cryptography only amplify the magnitude of it's applications. This essentially means that any way you choose to secure a system using conventional methods, you can pump more money into a quantum implementation of the system which will be exponentially more secure than a conventional system. This is because quantum cryptography employs quantum algorithms to secure data which can only be solved in polynomial time using quantum computing for decryption. Conventional methods of encryption also employ polynomial time encryption, but not to the magnitude quantum encryption does.

To learn about the impact of cryptography in society, I read the following article by Franck Lin:
Cryptography's Past, Present, and Future Role in Society

The executive summary of Lin's book gives a really accurate perspective on the intersection of public policy and cryptography. "The Individual and Authority (defined as civil government, military, and corporations) have always had a complex relationship with cryptography. Craving digital privacy, individuals highly value the effectiveness and transparency of the algorithms protecting personal and financial secrets. On the other hand, governments want to intercept criminal communication, the military wants to maintain a proven military asset, and corporations, especially those that sell media, want to safeguard their multibilliondollar markets. These later desires often run counter to the privacy-rights of the individuals." (Lin 2010). Essentially, if you want a public entity such as the government to encrypt your crucial data and help protect your privacy from international threats, you must give up privacy to the government (such as the US govt) for them to protect you. Lin essentially defines the tradeoff between privacy and security. If you wish to be protected, you must sacrifice privacy to those whom offer services to protect you. "Quantum cryptology will end this decade-long struggle and also define who will finally win what cryptographic rights. However, the result of quantum cryptography is largely dependent on what precedents we establish in this generation." (Lin 2010). Here, Lin claims that the advancements in technologies such as quantum cryptography may help ease this battle between security and privacy, as the mechanisms are so strong we gain the ability to protect ourselves without assistance. "Quantum key distribution is currently experimentally possible and should be commercially feasible within a decade. The University of Cambridge and Toshiba have achieved transmission rates of 1 Mbit/s over 20 km of fiber and 10kbit/s over 100 km of fiber." (Lin 2010). The rest of the paper effectively describes all of the benefits gained, and how these new and more powerful quantum technologies resolve former social policy issues.

Reference:
Lin, F., (2010) Cryptography's Past, Present, and Future Role in Society WUSTL.

Monday, May 4, 2015

Blog Post Four - Peer Reviewed Paper

I recently stumbled upon the an interesting research paper that discussed applications of quantum computing on social networks.

Here is a link to the article, for those who wish to view it before I discuss it: Applications of Social Network using Quantum Computing

The abstract of the paper describes how social networks (ie networks such as Facebook, Twitter, LinkedIn, etc.) have to handle an extremely large volume of data daily, due to thousands of new registrants to sites such as these. It is explained that to handle and compute data efficiently and fast, we need to employ faster computing devices than classical computing. This is because classical computing is reaching the point where it is no longer able to run computations against data stores and datasets as large as some of the data repositories that some social networks now utilize. The paper claims that "As quantum computing has the capable of complex computing with ease and efficient, the social network analysis seems to be appropriate application for such type of environment" (Roa 2015).

Depiction of Quantum Social Networks | Image Credit

The peer-reviewed paper then continues to provide justification for the problem by explaining what is wrong big-data computation by classical computers. Some of the information in the introduction is very similar to explanations I gave in my first blog post for the introduction into quantum computing. The paper first explains the architecture and mechanisms of a classical computer: "A classical computer has a memory made up of bits, i.e. 1 or 0 which are used for all the computational purposes. In terms of physical representation, each can be physically realized through a macroscopic physical system, such as the magnetization on a hard disk or the charge on a capacitor"(Roa 2015).

The article then explains the fundamental advantage gained from using quantum computers as opposed to regular computers. "If a document has n-characters to be stored on the hard disk of a typical computer can be described as a string of eight numbers of 0s and 1s. The classical computer obeys the laws of classical physics. Whereas the quantum computer obeys the laws of quantum mechanical phenomea. The data operations take place with the help of its superposition and entanglement. A quantum computer is a device that harnesses physical phenomenon unique to quantum mechanics (especially quantum interference) to realize a fundamentally new mode of information processing. Quantum computing is a quantum computational operations are executed on a very small number of qubits (quantum bits)" (Roa 2015).

In simpler terms, this quantum mechanism effectively allows us to compute these large sets of data while only using a small number of qubits, while still gaining the same performance that a significantly larger number of classical bits would yield. Of course, this means that we would have to write brand new code and architecture support for our social networks using these new technologies. In order to exploit the use of quantum machines, software must be written in ways that use quantum algorithm to conduct data analytics.

Comparison between quantum and classical computing (Roa 2015)

The research conducted concluded that " It is obvious that quantum computing will be a far better choice than traditional computing devices for complex and large data compilation with time constraints" (Roa 2015). It was concluded that having huge data set with a complex mapping in between the data will be an appropriate example for being getting executed in quantum computing environment. Social networks handle vast volumes of data and with passing of each day thousands of new entrants are joining the social sites, increasing the size of data.


Reference:
Roa, B., Mohapatra, Sonali., Saha, Ujjal., Mitra, Anirban. (2015). Applications of Social Network using Quantum Computing. ICIDRET.

Wednesday, April 29, 2015

Blog Post Three - Important Researcher: Andrea Morello

My previous two blog posts have included both an introductory video to quantum computing that Andrea Morello shot, and blog post about ground-breaking research that Andrea Morello and his team have recently accomplished. I thought that because of this, what better important researcher to focus on than Andrea Morello himself? 

Depicted: Andrea Morello | Photo Credit

A quick Google search for the most influential researchers in quantum computing thus far yielded the following list by David Toyli (PhD in Physics, UCSB):
Here's a list of prominent experimentalists, organized by topic.  It's certainly not exhaustive, but covers most of the main approaches.  
Superconducting Qubits (covered pretty well by Nicholas Grabon):
Trapped Ions:
Spins in semiconductors:
Linear Optics 
I thought I would include the list in case you were interested in other researchers as well, since this blog has primarily focused on Morello's research. As can be seen in his list, Andrea Morello made the list as one of the most influential researchers for quantum computing research focused on "Spins in semiconductors" (A field of quantum computing).

Achievements and Revolutionary Research of Andrea Morello 

Andrea Morello is currently serving as the head of the Quantum Spin control group at CQC2T. His research is said to be "the forefront of quantum technologies", as he demonstrated the world's first single-shot spin readout in silicon, and additionally the first spin quantum bits based on the electron and nucleus of a single phosphorus atom in silicon.

He has received the following awards as a result of these achievements:

  • 2011 Eureka Prize
  • 2013 Malcom McIntosh Prize for Physical Scientist of the Year
  • 2013 David Syme Research Prize
  • 2014 NSW Science and Engineering Award
Among the newer things he is working on, he is currently working on methods to control interaction between two qubits and develop a quantum logic gate. A quantum logic gate is a logical unit that can be used to perform operations on sets of bits, similar to the binary logic of an ALU but using quantum mechanics. The end goal of the development of this gate is to transport information across silicate crystals without corrupting data of other quantum gates. In addition to this project has his current most important focus. Andrea has also contributed to the decoherence problem in dipolarly-coupled spins. He is interested in solving this problem by using spin quebits to test models of coherence and fundamental quantum computing issues.


Sunday, April 26, 2015

Blog Post Two - A New Breakthrough for Silicon in Quantum Computing

You may recall last week that I posted an introductory video to help explain quantum computing. In the introductory video, Andrea Morello, a researcher at the University of New South Wales, gave a very clear introduction to the very complex topic of quantum computing. As it turns out, as of just yesterday, Morello and his research team have just discovered a new breakthrough in quantum computing! I was excited to discover that Morello, a researcher I did not know about until last week, had literally just made a new discovery!

Picture of Andrea Morello, Photo Credit: Marcus Eno

The news article was published in Cosmos Magazine (Not to be confused with Cosmo!).
Here is a link to the article which published Morello's breakthrough:


You will recall from my last post a brief discussion of the quantum bit (Qubit), and that it has the ability to maintain the state of 1 and 0 at the same time, creating a super-position. The qubits bits have been made out of a variety of elements that researchers have been testing. Morello and his research team have been trying to use the properties of silicon, by taking a single phosphorus atom entombed in a silicon crystal. If we were able to change the state of silicon qubits using only a single electrical charge/pulse, it would significantly lower the current cost of manufacturing these quantum machines in addition to opening an entirely new array of possibilities.

In order to read the super-position states of the quantum bits, Morello uses magnetic field generators, which according to the article, cost "around $100,000 a pop" (O'Connell 2015). The article continues to explain that "If they had to use one for each quantum bit in a large array, the cost would be astronomical. There is also a practical problem. Magnetic fields spread, making it impossible to control one quantum bit in an array without inadvertently affecting all its neighbours" (O'Connell 2015).

The breakthrough Morello's team and an experimental physicist named Arne Laucht discovered is that they found a way to control each quantum bit using a simple electrical pulse, as opposed to using a magnetic field generated to control each quantum bit. This is significantly more practical and opens up so many more doors for these silicon quantum computers. "Instead of each phosphorus atom having a dedicated magnetic field generator to control it, their new design floods the whole device with a single magnetic field" (O'Connell 2015). It was also mentioned that if the electrical pulses were timed properly, it could avoid the problem of unwanted affecting of neighboring qubits.

Essentially, this breakthrough will significantly reduce the cost of quantum computers in addition to improving their accuracy. The cost is improved due to needing fewer magnetic field generators to control qubit positions, and the accuracy is improved due to neighboring fields not confusing eachother's super-positions via alteration of magnetic polarities. I wish Morello and his team the best of luck in their future research and hope to hear about more advancements to silicon quantum computers in the near future!

Tuesday, April 21, 2015

Blog Post One - An Introduction to Quantum Computing and Cryptography

Before you read deeply into this blog, it is crucial you understand the basic concept of quantum computing. While the complexity of the subject is vast as many of quantum computing's capabilities and applications continually being discovered, this emerging field will likely shape our way of life as we know it as research progresses.

In order to understand what "quantum" computing is, you must first understand the difference between regular computing and "quantum" computing. The difference is literally in the physical properties of the bits, combining the physicality of quantum properties at the atomic level to alter how we can compute and read streams of bits. In traditional computing, these streams of bits can be directly translating into 1s (the bit is on) or 0s (the bit is off). We do this by passing positive (1) and negative (0) charges of voltage through ICs (Integrated Circuits). Computers can read binary streams of data (sequences of 1s and 0s), and convert them into useful instructions and operations to perform tasks. In traditional computing, each bit will only maintain a state of either 1 or a 0, but never neither nor both. This is not the case in quantum computing which uses Qubits. For a thorough explanation of this fundamental difference, I have provided a video below which I highly encourage all of you to watch:


Andrea Morello is a scientist from the University of New South Wales (depicted in the video). He explicitly states towards the end of the video that Quantum Computing has very special applications and specifically mentions that it is only useful in scenarios that can exploit the use of quantum algorithms. Morello continues to explain that "Quantum Computing is not a replacement for classical computers" and mentions that they are not universally faster than normal computers. He explained that for typical tasks such as watching a video or creating a document, normal computers would likely be faster. The key point Morello mentions is: Quantum computers don't perform operations faster than normal computers, but the number operations required to resolve at a result is exponentially smaller. 

One of the niche uses where we can exploit the quantum computer's property to make the number operations required to resolve at a result is exponentially smaller is Cryptography. Cryptography is a field where we use mathematical algorithms to encrypt and decrypt (encode or decode), information (sequences of bits). The purpose of doing this is to secure information so that only those people whom we wish to have the right/privilege to view the information are able to do so while others are not. An example which easily explains this concept is when you purchase something from an online vendor using a credit card. Your credit card information is encrypted, the message is send through the internet, and decrypted once it reaches the vendor's server computer so that they may use your credit card number. We encrypt the information so that if some other party on the network you were using intercepted the information, it would be completely erroneous and unusable as the data would not be represented sensibly.

Now that we understand the basic concepts of quantum computing and uses of cryptography, we can discuss while the concept of Quantum Cryptography is so important. I will go into detail in a later post, but here some food for thought, for now. Watch the following video on Heisenberg's uncertainty principle so you can better understand the physical randomness quantum cryptography offers:


Quantum cryptography uses the uncertainty of measuring particles to generate randomness in quantum algorithms. This randomness helps create algorithms which are virtually impossible to decrypt. Quantum cryptography uses Heisenberg's uncertainty principle as a basis for creating a random algorithm to encrypt data. “The principle bounds the uncertainties about the outcomes of two incompatible measurements, such as position and momentum, on atomic particles” (Berta, 2010). “It implies that one cannot predict the outcomes for both possible choices of measurement to arbitrary precision, even if information about the preparation of the particle is available in a classical memory” (Berta, 2010).



Reference:
Berta M., Christandl, M., Colbeck, R. Renes, J, Renner, R. (2010) The Uncertainty Principle in the Presence of Quantum Memory. Macmillan Publishers