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  • Writer's pictureDAVID MITLYNG

Weekly Takeaway-October 20,2023

Theme of the Week

Security through Quantum Mechanics One of the fundamental principles of quantum mechanics is the Observer Effect. All small particles are in a superposition of many quantum states, but, once measured, "one knows its current state ." Most believe this is due to wave function collapse, but there are other interpretations. It is as though the full details of the quantum information is hidden within a box. You can measure one (and only one) property, but you can never "peek inside" and gain complete information. This quirk of quantum physics is the foundation for the security inherent in quantum communications, including the secure distribution of encryption keys known as quantum key distribution (QKD). It also lends itself well for secure time distribution, a critical resource for position, navigation and timing (PNT), networks, communications, and power grids. Time distribution today relies on easily hackable satellite RF signals and network time protocols (NTP). Indeed, security for timing doesn't exist the same way it does for encryption keys. But as the recent news articles below highlight, that needs to change. Last Week's Theme: The Future is Optical

Industry News


  • ITSF, Oct 30 – Nov 2, Antwerp, Belgium

  • UK National Quantum Technologies Showcase 2023, Nov 2, London, UK

  • SLUSH, Nov 30 – Dec 1, Helsinki, Finland

The More You Know...

If Alice wants to share a secret with Bob, she can put the information in a box and send to Bob. Eve, the eavesdropper, wants to know what is in the box. In normal communications, Eve simply looks inside. The information is compromised, and Alice and Bob are none the wiser. But now Alice has a box containing a particle in a superposition of quantum states. While you can't know all of the quantum details of this particle, you can extract information following these fundamental rules:

  • You can measure one, and only one, quantum property. This is analogous to asking a question: For example, you can ask about color ("are you black or white?") or you can ask about hardness ("are you hard or soft?"), but you can't ask about both ("are you white and soft?")

  • The outcome is repeatable - if you measure the same property. For example, if you ask about color a thousand times in a row, you will get the same answer - black or white.

  • However, the outcome is not repeatable - if you don't measure same property. For example, if you find out the color is white, but then ask about hardness, the next time you ask for the color it could be white or black.

These fundamental rules, proven out in many experiments, is described in this entertaining presentation based on the book "Quantum Mechanics and Experience." So in this case Eve still has the ability to intercept the box meant for Bob. Eve can only ask it one question, but won’t know what question to ask. If the wrong question is asked, then the outcome changes for Bob. We can extend this extremely simple example to QKD (apologies to all quantum physicists!): Alice and Bob exchange many boxes, each one potentially representing one of a string of bits that make up a shared encryption key. While this sounds like a convoluted process, it has an important result that doesn't exist in any other type of communications - the ability to detect Eve by looking at the results from a sample of the boxes. To learn more, please email us or schedule a meeting here.

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