8 ms·

Toshiba reports milestone in quantum cryptography

123 points by elahieh 5y ago

helsinkiandrew 5y ago
> The company says a research team has used quantum cryptography to securely send and store human genome data Unless I'm wrong, it appears to be a "milestone" in that they sent human genome data rather some other kind of data (I'm not sure how that is significant) and no new quantum cryptography breakthrough has been achieved?
- roemerb 5y ago
  Yeah I read this the same way. The article is very vague and does not mention anything concrete at all.
  - tinco 5y ago
    It's crazy how they messed up, the original Toshiba press release is super clear and even leads with this list of key points for media to use right up top: -New dual band stabilisation technique cancels the problem of temperature and strain fluctuations to allow long distance quantum communication -Quantum key distribution demonstrated on fibres of record 600km length -Significant advance towards building a global quantum internet
    - jacquesm 5y ago
      I don't see how the third follows from the second, wouldn't a Quantum internet that spans the globe always require point-to-point physical links between any two parties that want to trust each other?
      - detaro 5y ago
        "point-to-point" links can be circuit-switched at least, so you don't need an actual full mesh.
      - Strilanc 5y ago
        Why would it need to be end-point to end-point? Just have routers continuously build up entanglement with their neighbors, do entanglement swapping along packet-switched paths, and then use the entanglement to teleport via the classical internet.
ekianjo 5y ago
Quality NHK reporting very poor on actual details as usual.
tinco 5y ago
There's a better article here (which is the source): https://www.toshiba.eu/pages/eu/Cambridge-Research-Laboratory/toshiba-announces-breakthrough-in-long-distance-quantum-communication https://www.toshiba.eu/pages/eu/Cambridge-Research-Laborator... Basically their achievement is that they have done quantum key distribution over a distance of 600km, which is apparently a world first. And I suppose it demonstrates commercial viability. For people not familiar with the idea: They didn't send a genome over the quantum channel, they sent a private key over the quantum channel, and then encrypted the genome with that key using conventional encryption, and then sent that encrypted genome over a conventional network. Without QKD this process would have been done using public key encryption, which means the sender would have to have received the public key from a trusted source, usually you trust that source because a third source trusts it, etc, this is called the chain of trust. You can see how if a malicious party injects itself into the chain of trust the confidentiality is broken. With QKD you only have to trust that the person you want to talk to is on the other side of the quantum link you've established, i.e. the security is put firmly in the physical realm. Because of the quantum entangling properties of this link, a malicious party can't inject itself physically in the middle of this link, and can not eaves drop or manipulate it.
- definataly 5y ago
  >> can not eaves drop More precisely, it is possible to know if someone is eavesdropping and halt the key sharing. QKD does not prevent it, but has a provable method to know that someone is listening (statistics of the measurements change).
  - guyomes 5y ago
    > QKD does not prevent it, but has a provable method to know that someone is listening Unless some breakthrough in physics of particles, where all is not fully understood yet. A bit like standard cryptographic protocol are safe unless some breakthrough in mathematics or computer science.
- fsh 5y ago
  This is not quite correct. QKD could in principle be safe against eavesdropping (even though the track record so far has been very poor due to experimental imperfections), but it has no inherent protection against man-in-the-middle attacks. If you think about it, this is fundamentally not possible. There is no way of authenticating who sits on the other end of your fiber connection without having previously exchanged a key. This could either be a shared secret key, or standard public key cryptography. From an it-security perspective, QKD is simply a very expensive and impractical stream cipher that (slowly) grows a short shared secret key into an arbitrarily long one. The only fundamental advantage over a symmetric encryption algorithm like AES is that an attack would have to happen during the QKD process when the (signed) basis settings are exchanged. It is not possible to simply record all the communication with the hope to maybe being able to break the algorithm in the far future.
sharmin123 5y ago
https://www.hackerslist.co/how-to-hack-facebook-account-is-it-possible/ https://www.hackerslist.co/how-to-hack-facebook-account-is-i...
tofukid 5y ago
Can someone explain how this is a breakthrough compared to China's satellite system which achieved QKD in 2016? They also claim "ground-based QKD to beyond 500 km using a new technology called twin-field QKD" https://scitechdaily.com/china-builds-the-worlds-first-integrated-quantum-communication-network/ https://scitechdaily.com/china-builds-the-worlds-first-integ...
- heavenlyblue 5y ago
  By the way, how does this work over the radio? Does that mean that adding an antenna that captures the signal in the middle would affect the statistics of the received signal? What does it mean to have a “receiving antenna” in this case if any antenna can receive signals of any frequency?
aomobile 5y ago
Even if quantum crypto reaches distances of 100‘000km it would still not mean we can use it at home I suppose, because just having one switch/router between Alice and Bob would break the scheme, no?
- hannob 5y ago
  I'm not entirely sure why this comment gets downvoted, because it's spot on. QC is impractical for any real-world network, and the idea that it could ever play a role in the real-world Internet is just fantasy. But also we don't need to. Cryptography without quantum is just fine.
deleted 5y ago
[deleted]
devwastaken 5y ago
We need a down to earth real guide on quantum, because many are convinced that superposition and entanglement are somehow communication and/or trust mechanisms. In reality entanglement simply means that one particle spins the opposite of another particle it's entangled with. They could already have been this way from entanglement, but we don't know it's actual state until observation (with scientific instruments small enough to read the spin of a particle, not eyes). I'm probably completely wrong too.
- drdeca 5y ago
  No, entanglement does not just mean “it is in one of these two states but we haven’t measured which”. Entanglement is what you get when you have a state in the tensor product of two systems which is not a tensor product of a single state from each system, but is instead a linear combination of such products. There are, in fact, experiments that can be (and have been) done which distinguish between “these two particles are entangled” and “we don’t know which of two combinations of states these two particles are in”. However, if you only have one particle of the entangled pair, and don’t have any other way of getting information from the other particle, you can’t distinguish it from just, a probability mixture of (superpositions of) states of the one particle. I say “(superpositions of) states of the one particle” to emphasize that the states don’t have to be in one of the standard basis states with a nice name like “up” or “down”, (though you could use a different basis in which it is a basis state).
randomopining 5y ago
What does this mean for teh bitcoins?

123 points by elahieh 5y ago

> The company says a research team has used quantum cryptography to securely send and store human genome data Unless I'm wrong, it appears to be a "milestone" in that they sent human genome data rather some other kind of data (I'm not sure how that is significant) and no new quantum cryptography breakthrough has been achieved?

roemerb 5y ago
Yeah I read this the same way. The article is very vague and does not mention anything concrete at all.
- tinco 5y ago
  It's crazy how they messed up, the original Toshiba press release is super clear and even leads with this list of key points for media to use right up top: -New dual band stabilisation technique cancels the problem of temperature and strain fluctuations to allow long distance quantum communication -Quantum key distribution demonstrated on fibres of record 600km length -Significant advance towards building a global quantum internet
  - jacquesm 5y ago
    I don't see how the third follows from the second, wouldn't a Quantum internet that spans the globe always require point-to-point physical links between any two parties that want to trust each other?
    - detaro 5y ago
      "point-to-point" links can be circuit-switched at least, so you don't need an actual full mesh.
    - Strilanc 5y ago
      Why would it need to be end-point to end-point? Just have routers continuously build up entanglement with their neighbors, do entanglement swapping along packet-switched paths, and then use the entanglement to teleport via the classical internet.

ekianjo 5y ago

Quality NHK reporting very poor on actual details as usual.

tinco 5y ago

There's a better article here (which is the source): https://www.toshiba.eu/pages/eu/Cambridge-Research-Laboratory/toshiba-announces-breakthrough-in-long-distance-quantum-communication https://www.toshiba.eu/pages/eu/Cambridge-Research-Laborator... Basically their achievement is that they have done quantum key distribution over a distance of 600km, which is apparently a world first. And I suppose it demonstrates commercial viability. For people not familiar with the idea: They didn't send a genome over the quantum channel, they sent a private key over the quantum channel, and then encrypted the genome with that key using conventional encryption, and then sent that encrypted genome over a conventional network. Without QKD this process would have been done using public key encryption, which means the sender would have to have received the public key from a trusted source, usually you trust that source because a third source trusts it, etc, this is called the chain of trust. You can see how if a malicious party injects itself into the chain of trust the confidentiality is broken. With QKD you only have to trust that the person you want to talk to is on the other side of the quantum link you've established, i.e. the security is put firmly in the physical realm. Because of the quantum entangling properties of this link, a malicious party can't inject itself physically in the middle of this link, and can not eaves drop or manipulate it.

definataly 5y ago
>> can not eaves drop More precisely, it is possible to know if someone is eavesdropping and halt the key sharing. QKD does not prevent it, but has a provable method to know that someone is listening (statistics of the measurements change).
- guyomes 5y ago
  > QKD does not prevent it, but has a provable method to know that someone is listening Unless some breakthrough in physics of particles, where all is not fully understood yet. A bit like standard cryptographic protocol are safe unless some breakthrough in mathematics or computer science.
fsh 5y ago
This is not quite correct. QKD could in principle be safe against eavesdropping (even though the track record so far has been very poor due to experimental imperfections), but it has no inherent protection against man-in-the-middle attacks. If you think about it, this is fundamentally not possible. There is no way of authenticating who sits on the other end of your fiber connection without having previously exchanged a key. This could either be a shared secret key, or standard public key cryptography. From an it-security perspective, QKD is simply a very expensive and impractical stream cipher that (slowly) grows a short shared secret key into an arbitrarily long one. The only fundamental advantage over a symmetric encryption algorithm like AES is that an attack would have to happen during the QKD process when the (signed) basis settings are exchanged. It is not possible to simply record all the communication with the hope to maybe being able to break the algorithm in the far future.

sharmin123 5y ago

https://www.hackerslist.co/how-to-hack-facebook-account-is-it-possible/ https://www.hackerslist.co/how-to-hack-facebook-account-is-i...

tofukid 5y ago

Can someone explain how this is a breakthrough compared to China's satellite system which achieved QKD in 2016? They also claim "ground-based QKD to beyond 500 km using a new technology called twin-field QKD" https://scitechdaily.com/china-builds-the-worlds-first-integrated-quantum-communication-network/ https://scitechdaily.com/china-builds-the-worlds-first-integ...

heavenlyblue 5y ago
By the way, how does this work over the radio? Does that mean that adding an antenna that captures the signal in the middle would affect the statistics of the received signal? What does it mean to have a “receiving antenna” in this case if any antenna can receive signals of any frequency?

aomobile 5y ago

Even if quantum crypto reaches distances of 100‘000km it would still not mean we can use it at home I suppose, because just having one switch/router between Alice and Bob would break the scheme, no?

hannob 5y ago
I'm not entirely sure why this comment gets downvoted, because it's spot on. QC is impractical for any real-world network, and the idea that it could ever play a role in the real-world Internet is just fantasy. But also we don't need to. Cryptography without quantum is just fine.

deleted 5y ago

[deleted]

devwastaken 5y ago

We need a down to earth real guide on quantum, because many are convinced that superposition and entanglement are somehow communication and/or trust mechanisms. In reality entanglement simply means that one particle spins the opposite of another particle it's entangled with. They could already have been this way from entanglement, but we don't know it's actual state until observation (with scientific instruments small enough to read the spin of a particle, not eyes). I'm probably completely wrong too.

drdeca 5y ago
No, entanglement does not just mean “it is in one of these two states but we haven’t measured which”. Entanglement is what you get when you have a state in the tensor product of two systems which is not a tensor product of a single state from each system, but is instead a linear combination of such products. There are, in fact, experiments that can be (and have been) done which distinguish between “these two particles are entangled” and “we don’t know which of two combinations of states these two particles are in”. However, if you only have one particle of the entangled pair, and don’t have any other way of getting information from the other particle, you can’t distinguish it from just, a probability mixture of (superpositions of) states of the one particle. I say “(superpositions of) states of the one particle” to emphasize that the states don’t have to be in one of the standard basis states with a nice name like “up” or “down”, (though you could use a different basis in which it is a basis state).

randomopining 5y ago

What does this mean for teh bitcoins?