36C3: Build Your Own Quantum Computer At Home

In any normal situation, if you’d read an article that about building your own quantum computer, a fully understandable and natural reaction would be to call it clickbaity poppycock. But an event like the Chaos Communication Congress is anything but a normal situation, and you never know who will show up and what background they will come from. A case in point: security veteran [Yann Allain] who is in fact building his own quantum computer in his garage.

Starting with an introduction to quantum computing itself, and what makes it so powerful also in the context of security, [Yann] continues to tell about his journey of building a quantum computer on his own. His goal was to build a stable computer he could “easily” create by himself in his garage, which will work at room temperature, using trapped ion technology. After a few iterations, he eventually created a prototype with KiCad that he cut into an empty ceramic chip carrier with a hobbyist CNC router, which will survive when placed in a vacuum chamber. While he is still working on a DIY laser system, he feels confident to be on the right track, and his estimate is that his prototype will achieve 10-15 qubits with a single ion trap, aiming to chain several ion traps later on.

As quantum computing is often depicted as cryptography’s doomsday device, it’s of course of concern that someone might just build one in their garage, but in order to improve future cryptographic systems, it also requires to fully understand — also on a practical level — quantum computing itself. Whether you want to replicate one yourself, at a rough cost of “below 15k Euro so far” is of course a different story, but who knows, maybe [Yann] might become the Josef Prusa of quantum computers one day.

20 thoughts on “36C3: Build Your Own Quantum Computer At Home

        1. Using quantum tech can transmit data such that it cannot be read in transit without rendering the sent data invalid.

          IOW, you can tell if something is listening the instant eavesdropping starts.

          1. Something that likely can’t easily be done in the electrical domain, rendering such security measures rather pointless in practical use in a network with more active switching then most people care to poke a stick at.

            Most such systems that I have seen have usually been in regards to fiber optics communication. As to secure against eavesdropping along that fiber. At the ends however, it is converted back into digital signals traversing a regular PCB, ie, eavesdropping can be done here. Though, at least it is in some ISP/network-providers hopefully more secure premiss, and hopefully they aren’t have any shady business behind the scenes.

            It is generally very hard to have truly secure channel of communication. Though, eavesdropping is usually easily avoided by the use of a shared key sent via a known secure channel. (Like personally escorting a USB thumb drive with a many GB large cryptographic key to the datacenter/server you desire to connect to. But the impracticalities of doing this makes it very rarely used.)

            Though, even with strong encryption, the nature of the network traffic, ie package size and frequency can spoil a lot about what you are doing, even if encrypted with one time pad. Then there is always other forms of tempest for an attacker to exploit as well…

            One could theoretically have a dedicated fiber from one’s own premiss going directly to the server of interest. But this is both very cost prohibitive, and even more impractical compared to personally escorting thumb drives around the world….

            Not that any of those two solutions are practical for most people.

    1. IMO large key lengths are still sufficiently hard that they’re going to need the quantum computer of year 2050 to break them in a reasonable amount of time. i.e. they need the 4Ghz i7 of quantum CPUs, not the little proof of concept ALU they’re tinkering with so far. (That’s an analogy, don’t go telling me that it isn’t actually an ALU) Billions of qubits are needed. I believe that methods using a few thousand qubits and iterative techniques can knock a few powers of 10 off the time required to compute, but that only shortens security of “serious” crypto from “until the heat death of the universe” to “until the oceans boil away due to our sun entering red giant phase.”

      1. Not sure where you are getting billions, you need 2n+1 qubits using shor’s algorithm to factor an N bit number made from primes. So for a 1024 bit RSA key you would need 2049 qubits. The time it takes for the circuit to complete its’ computation depends on your hardware architecture, for a linear optic quantum circuit implementation of shor’s algorithm, you’re looking at a hardware cost of $30 Million, a circuit length of 5 football fields, and will be able to break a 1024 bit key on average every 5-7 minutes (if we are factoring in success/failure probabilities of the gates and assuming a cheapo 2.5Ghz processor is being used to verify the keys). That’s without any optimization either, mind you. Just stock KLM protocol implementation with a simple checking algorithm to brute force the key.

        All that is to say, yes, it is possible, yes, the government is experimenting with this, we do not know whether they’ve successfully built such a computer, but I would wager that if they haven’t yet, it is not more than a few years a way.

  1. There was quite some giggling in the audience, not much of a surprise. Still I think this is great and important work. All this stuff Google and IBM are doing is pretty far away from practical uses and things like temperatures below 1 Kelvin will never be practical. Yann approaches this from the opposite direction and if he succeeds with just two qubits, we’ll have something usable by everybody.

  2. -I’ve been building my projects in my garage.
    -Me too!
    -Really! The last one I build was a spice rack, and you?
    -I built a quantum computer that works under the ion trap principle; getting the lasers to work properly was the hardest part.
    -I… have to go… to another place… whit regular people… where you are not present… now… bye

  3. Spoiler: he didn’t really build a QC. He didn’t even build the laser assembly. He did build few parts but he’s nowhere even close to having a working QC. This whole talk is just clickbait.

  4. I am more of a power plant guy. I’ve been collecting some firebricks for the fusion reactor that I am building in my garage. I am guessing we will finish our projects at the same time with this guy.

  5. its that simple? stop the presses! tell IBM and Google to drop the multimillion dollar research programs! We’ve got quantum supremacy in a garage box! I wonder who feels the worst, the highly paid technicians and scientists whose life work was just surpassed, or the executives who paid those guys large amounts of money for the same result? I know, its quantum! so both results exist at the same time! :)

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