Since I revisited the topic of AES encryption and NSA surveillance the Washington Post published information sourced through Edward Snowden that the NSA is spending $79.7 million to pursue a quantum computer capable of running Schor's algorithm. If and when the NSA succeeds, all the currently-unreadable AES-encrypted data they routinely capture en masse from internet backbones and stored in the Bluffdale, Utah computing center would become readable.


To give some sense of the agency's ambition we need to talk about Schrödinger's cat.

 

Quantum Smearing

 

In Erwin Schrödinger's famous thought experiment a cat sits inside a Faraday Cage--a steel box from which electromagnetic energy cannot escape. Also in the box and inaccessible to the cat is a machine that contains: 1) some material whose probability of releasing radiation in an hour is exactly 50%; 2) a Geiger counter aimed at the material and rigged to release a hammer upon detecting any release of radiation; 3) a flask of poison positioned under the hammer. If the radioactive material releases radiation, the hammer smashes the flask, killing the cat.

 

In this box, however, as a quantum system, it is always equally probable that radiation is released and not released. Says the Copenhagen interpretation of quantum systems, with the idea of superposition, the cat in the box exists as a smear of its possible states, simultaneously both alive and dead; an idea Schrödinger along with Einstein ridiculed for being absurdly at odds with everyday life. Nobody has ever seen the material smear that is a Schrödinger cat*.

 

Qubits, or Herding Schrödinger Cats

 

David Wineland and team received their Nobel Prize in Physics in part for creating a very small Schrödinger cat. "They created 'cat states' consisting of single trapped ions entangled with coherent states of motion and observed their decoherence," explains the the Nobel Prize organization in making their 2012 award.

 

Wineland developed a process to trap a mercury ion, cause it to oscillate within the trap, and then use a laser to adjust its spin so that the ion's ground state aligns with one side of its oscillation and its excited state aligns with the other side. On each side of the oscillation the ion measures 10 nanometers; the ion's two resting points in the oscillation are separated by 80 nanometers. And in effect, the mercury ion is guided into a "cat state" of superposition.

 

In this state the ion has both a ground and excited charge and so meets the physical requirement for serving as a quantum computing "qubit"; using the difference in spin, superposition allows the ion to be both 0 and 1 depending on where in its oscillation it is "read".

 

A quantum computer would be capable of breaking AES because a qubit is an exponential not a linear quantity. For example, in linear binary computing, using electrical current transistors, 3 bits of data can give you 1 binary number--101, 001, 110, etc.; but in quantum computing, 3 qubits represent a quantity that is 2 to the 3rd.

 

So, to extrapolate how qubits scale, Wineland (43:00) offers this example: while 300 bits in linear computer memory may store a line of text, 300 qubits can store 2 to the 300th objects, holding a set that is much larger than all the elementary particles in the known universe. And qubit memory gates would allow a parallel processing quantum computer to operate on all of its 2 to the nth inputs simultaneously, making trivial the once-untouchable factoring problems upon which all currently known encryption schemes are based.

 

Big Black Boxes

 

The NSA project is underway in Faraday cages the size of rooms. Could that work proceed without the direct involvement of Wineland's award-winning NIST team? Even presuming that involvement, the technical challenges of going from an isolated and oscillating mercury ion to a fully developed quantum computing platform would seem to imply years not months of work.

 

This time next year we may know the answer to how long the project will take. In the meantime, we continue assuming that AES-encrypted data remains secure and that the SNMPv3-enabled tools for monitoring systems with secure data do not introduce breaches in the systems themselves.

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* Schrodinger implicitly formalized his own feline paradox with a differential equation that calculates the state and behavior of matter within quantum systems as a wave function (Ψ) that brings together mutually exclusive possibilities.