Not heard of this until I read this article:
Wikipedia:
Any thoughts? 
āUnhackableā definitely deserves quotes. 5 years ago I had a lecture from guy who had successfully hacked one of these systems.
4 Likes
Eh, except quantum encryption like this really is considered mathematically, well, not necessarily unhackable, but ānoticableā. Sure you can get a packet of data out of it, but in doing so the receiver never gets it or gets it altered, thus alerting them to the attempt. So you can get data out of it as a third party, but they will just stop after a single packet or so.
And I really really doubt that happened 5 years ago since we did not have the technology for it then. 
4 Likes
Sure you can get a packet of data out of it, but in doing so the receiver never gets it or gets it altered, thus alerting them to the attempt.
exactly
This quantum stuff is always a fascinating read, but the idea is that the reality on the smallest scale is nothing logical, but pure weirdness 
In case of quantum cryptography itās about the act of measurement (or observation) that changes the observed object, this way anyone who eavesdrops automatically ācorruptsā the sent data. So the unhackability claim is not that unrealistic.
I also wonder how the programming of quantum computers will look like, something alongside the true, false and true and false booleans 
There are lots of advancements in the field Quantum computing and quantum supremacy, explained | WIRED UK
Itās an interesting time we live in
1 Like
The idea here is not to be able or not to hack, itās to know when you are getting hacked, so probably the system can identify it and act upon. 
1 Like
Nothing of the sort actually. Quantum computers are actually horribly inefficient for āclassicalā computing work. They really come into usefulness when you get certain parts of āoperationsā that can be done in massively parallel ways but where you can also āentangleā the inputs in such a way that the outputs get entangled as well to get the result you want. It is very much a kind of dance in math, but if it works for you problem space than all the better for it.
As one example, current cryptography works by having 2 very large prime numbers multiplied together, and you have to reverse that, I.E. factoring. Well quantum computers are as bad at factoring as classical computers. However there is one tiny little operation in factoring that if you split it up juuuust right happens to be the āslowā part, the loop with everything else that can be put outside of it or so. That operation has a quantum math operation, named the Shorās Algorithm, that can be done that entangles the particles in just the right way that you can do āthatā operation quickly, which then makes prime number factoring from, say, O(log(N)^256) or so down to O(N*4) (basically constant) when you have a classical computer do the rest of the before and after operations.
Also a lot of that article is hogwashBuzzWords, sure it is accurate but does not really explain just how hard the math is. A quick youtube search with no sound (Iām at work, no sound) implies that these two videoās explain the real difficulty much more accurately:
3 Likes
For me one question I have is ā¦ how much does it actually matter if you can intercept communication if simply observing it will effect the message. So basically the receiving application will notify the user that this message has already been seen or destroy it. If it destroys the message, then basically anyone can effectively prevent communication by simply observing it.
So itās kinda like a choice between denial of service or lack of privacy. Seems like a lot of tech involved just to let you know that itās happening. But I guess that how everything is at first during transitions in technological shifts right?
2 Likes
Usually you donāt exchange the message, but the key only. The message itself is then transmitted on another way. This way the sender and receiver can see if a given key has been compromised before even using it to encrypt the message and try to negotiate another one.
3 Likes
Precisely this, this is why it is actually quite a secure setup.
2 Likes
Nothing of the sort actually. Quantum computers are actually horribly inefficient for āclassicalā computing work.
Yep, I know (the theoretical part, not the math :)) The booleans statement was kinda joke based on the fact that the qbits have an extra superposition state. But honestly if these things spread we might need another programming paradigm change.
Iām not totally sold on them sucking at classical computing though, I remember the time when LSD vs CRT monitors was totally āa thingā and the fact that CRT will have itās niche was just that: a fact Same with VCR and what not, weāll see where we get with these computers when we get there.
The vids barely touch the hardcore math (which I wouldnāt get anyway), but I enjoyed them -way past the working hours here, so thanks!
PS hereās a good one xkcd: Quantum Mechanics
2 Likes
In 2011, there was already a quantum network working in my city
2 Likes
No. the only new bit is the scope of this implementation of quantum key distribution. which is impressive.
I was working on these systems with fibre optics for the connection medium in 2011- 2012.
By hacked I mean that the end users were unaware of an eves dropper, i.e. completely compromised. The theory proves the system is unhackable for a perfect implementation. Unfortunately a perfect implementation is impossible.
As with many hacks the trick is to change abstraction level. The hack I was show was able to trick the detectors into thinking they had received one photon in a window where they had in fact received many photons, thus upsetting the trigger voltages for the detectors.
An update on this story:
1 Like
Another related story:
And the worldās first intercontinental video call protected by a quantum key was successfully carried out about a week agoā¦
1 Like
