Dailydave mailing list archives
Re: Quantum Key Distribution
From: Matt Tait <matt.tait () gmail com>
Date: Thu, 17 Aug 2017 20:41:39 +0100
if I had to venture a guess as to why there seems to be growing interest
in QKD now: quantum computers are close enough to being practical that governments want to move ... I think this is true, but it just highlights that the people funding QKD also don't understand it. Quantum computers are good way to break current-gen crypto. They suck at breaking next-gen crypto. And QKD sucks at making secure crypto in any gen. The only problem QKD solves is "how do I get more funding for my physics group studying entanglement". On Aug 17, 2017 2:21 PM, "Tyler Nighswander" <tylerni7 () gmail com> wrote: As a whole QKD between two not terribly far points is not interesting. People don't really care about just another random free space point-to-point quantum transmission (even if it's slightly further than the last one). However, satellite QKD has a few interesting things that are active areas of research/areas with very practical consequences: * very long distance free space transmissions with tolerable bandwidth/errors * QKD with moving objects (like airplanes or satellites) in general * quantum networking To me, quantum networking (establishing a good way to set up QKD between two arbitrary places) is really the main advantage and cool part of satellite based QKD. DARPA has been working for around a decade on a small quantum network, for example, but that requires mostly fiber and some short line-of-site hops. Scaling that up is not going to be easy; there's been some research on using existing fiber lines for quantum communication, but you'd have to replace all the networking equipment with quantum networking equipment that is entanglement preserving, and that's a huge pain. If instead you have a satellite network, you now can get relatively easy QKD between any pair of ground stations without having to worry about updating vast amounts of infrastructure around the country, and that's the real advantage: not satellite-earth communications, but earth-(satellite-)earth key establishment between potentially very distant places. I don't know enough about the requirements for satellite tracking for QKD to know if that has practical applications for tracking satellites without "cooperation", but I would guess it does not. For what it's worth, the numbers I read in the paper are a satellite of 7.6km/s and a beam width at the satellite of around 10m. That sounds neat, but not "military satellite tracking technology" impressive. That sounds like a far less strict requirement than for GNSS satellites. As for the original point, if I had to venture a guess as to why there seems to be growing interest in QKD now: quantum computers are close enough to being practical that governments want to move their asymmetric secure comms (no idea how much they use this vs just symmetric crypto). If quantum computers capable of useful cryptanalytic attacks are 40 years away (that may be a bit ambitious), and it will take 10 years to implement QKD networking for government's most sensitive data (that definitely seems ambitious), that's accepting that data can be decrypted 30 years after it was transmitted. That's fine for my personal banking information; that's not fine for lots of sensitive government data. Maybe they received some intelligence that other groups are simply taking quantum computing seriously. It would be quite a risky bet to say if the NSA is putting significant resources towards quantum computing (and they probably are?) that they won't have practical results for several decades. So basically: quantum computing is coming slowly, but it's a legitimate concern; and satellites are interesting because they represent a practical way to stand up complex quantum networks. On Sat, Aug 12, 2017 at 5:40 PM, Alfredo Ortega <alfred () groundworkstech com> wrote:
I don't see it as much as a QKD advancement but as a Satellite and tracking advancement, as you have to somehow receive individual photons from earth while orbiting at 30 km/s. And if you can track your satellites this accurately, you can track everybody elses. On 11/08/17 03:41, Jean-Philippe Aumasson wrote:Mostly PR I believe. With this satellite-QKD thing the Chinese probably want to show their own expertise (if they built this alone and not with Western companies), whereas a couple years ago they were discussing with IdQuantique and others to build QKD backbones. Are the Chinese into "quantum supremacy" projects like Europeans? I don't see satellite-QKD as a way to defeat future (?) quantumcomputers,cos satellite-to-earth coms are usually symmetric-crypto based, something unbroken by a QC. BTW QKD research doesn't have much to do with QC. On Thu, Aug 10, 2017 at 5:42 PM dave aitel <dave () immunityinc com> wrote:While nothing cryptographic has leaked from the Snowden documents to the public, Edward Snowden did give up a lot of things to the Chinese to get out of Hong Kong, and I notice that they've recently invested very heavily in Quantum Key Distrubtion (for example, shooting satellites up with entangled photons, etc.) So my question is: Is this something they learned about US/Russian capability against other cryptographics that we are not aware of? Did they study up and learn something themselves that we are not aware of? Or is this a total lark or PR stunt? Or maybe it's just not that much money to them, so they might as well? -dave _______________________________________________ Dailydave mailing list Dailydave () lists immunityinc com https://lists.immunityinc.com/mailman/listinfo/dailydave_______________________________________________ Dailydave mailing list Dailydave () lists immunityinc com https://lists.immunityinc.com/mailman/listinfo/dailydave_______________________________________________ Dailydave mailing list Dailydave () lists immunityinc com https://lists.immunityinc.com/mailman/listinfo/dailydave
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Current thread:
- Quantum Key Distribution dave aitel (Aug 10)
- Re: Quantum Key Distribution J.M. Porup (Aug 11)
- Re: Quantum Key Distribution dave aitel (Aug 11)
- Re: Quantum Key Distribution J.M. Porup (Aug 11)
- Re: Quantum Key Distribution dave aitel (Aug 11)
- Re: Quantum Key Distribution Matt Tait (Aug 11)
- Re: Quantum Key Distribution Jean-Philippe Aumasson (Aug 11)
- Re: Quantum Key Distribution Alfredo Ortega (Aug 13)
- Re: Quantum Key Distribution Tyler Nighswander (Aug 17)
- Re: Quantum Key Distribution Matt Tait (Aug 17)
- Re: Quantum Key Distribution Alfredo Ortega (Aug 13)
- Re: Quantum Key Distribution J.M. Porup (Aug 11)