4 ms·

Glad to see this but it doesn’t eliminate the issues surrounding how many less sophisticated encryption algorithms have been used. The millennium bug got fixed

by cenal 8y ago

Glad to see this but it doesn’t eliminate the issues surrounding how many less sophisticated encryption algorithms have been used. The millennium bug got fixed only because we put money into solving it. That kind of emphasis needs to be put behind addressing the forthcoming encryption crisis.

sgt101 8y ago
I don't think that there is an encryption crisis because there are post quantum schemes : https://en.wikipedia.org/wiki/Post-quantum_cryptography https://en.wikipedia.org/wiki/Post-quantum_cryptography I think that it is expected that these can / will be brought into use well before QC becomes widely used and therefore attackers will only have the opportunity to decrypt public key traffic that is many years old. Very short keys can already be attacked using GPU clusters, and it is clear QC will be limited in power for a long time, so traffic encrypted with long RSA keys will be safe for many years. Should extremely powerful QC be rapidly available, and should the public key quantum safe stuff be unworkable for some reason (for example very high speed transactions) then Quantum Key Distribution will provide an infrastructure to protect important traffic (financial institutions, markets, defence). The point here is that symmetric keys which are rather hard to break but fast to use can be distributed securely and rapidly and so can be changed very frequently meaning that attackers armed with fantastical QC would still have to spend vast resources to have any chance of reading traffic. I think that the moderate resources being employed today are a good hedge for society dealing with this issue.
- throwawaymath 8y ago
  > Quantum Key Distribution will provide an infrastructure... No. Quantum key distribution is a fugazzi. It's the red headed step child of actual cryptographic research in the quantum setting. Using quantum key distribution as the basis for a PKI would be ridiculously brittle and over-engineered. Note that the vast majority of interest and research on it comes not from cryptographers, but from physicists who are seeking a cryptographic problem to solve. It's like saying we should abandon the computational complexity theoretic model of cryptography and go back to the information theoretic model. Basically, it's fairy dust sprinkled onto a one time pad. In modern cryptography the one time pad is (approximately) never used because pseudorandomness is sufficient. Key distribution is not a problem which requires quantum computers to solve. Orchestrating a key distribution ceremony using computers that must extraordinarily well calibrated and synchronized using quantum entanglement would be inefficient and asinine, to put it bluntly.
  - akvadrako 8y ago
    QKD doesn't actually help with initial key distribution and you wouldn't use it for that anyway, so you are arguing against a straw man. What it does is let you expand your pre-existing shared keys in a provably secure manner. And it might be easy if you use satellites, like the Chinese are doing.
    - throwawaymath 8y ago
      I'm not arguing against a straw man, I'm outlining why it's unnecessary (in very blunt terms). What you've just said does nothing to refute everything I stated. "Provable security" is both rare and unnecessary in most of cryptography (in the information theoretic sense relevant to this discussion, not the sense of e.g. application security or static analysis). To reiterate: you do not need information theoretic security to defend against satcom intrusions. That's tantamount to using a one time pad, which is ridiculously inefficient. The computational model is just fine. Even the United States government only rarely uses information theoretic security these days, and instead opts for the more efficient computational security provided by e.g. AES.
  - sgt101 8y ago
    Quantum computers have nothing to do with QKD as far as I know. Instead you need things like this : https://www.toshiba.eu/eu/Cambridge-Research-Laboratory/Quantum-Information/Quantum-Key-Distribution/Toshiba-QKD-system/ https://www.toshiba.eu/eu/Cambridge-Research-Laboratory/Quan... Which detect photon's one at a time (also there is spitting out of photons via lasers) The idea is that you have an infallible alarm for when the optics have been tapped, which means that you can then send lots of symmetric keys and know that they can't be intercepted (provided you are only sending them ~50km. So it's nothing to do with cryptography (really) either - which explains why cryptographers aren't that interested in it. Also it's not a fugazzi as there are several working testbeds in the wild.
    - throwawaymath 8y ago
      A system for providing assurance against tamper detection during key distribution is pretty clearly germane to cryptography. Cryptography already provides very mature solutions for tamper detection. Like I said, information theoretically secure tamper detection is over-engineered and unnecessary.
- akvadrako 8y ago
  Did you read that wiki page? None of the asymmetric schemes are in widespread use and the blurbs for all except the Lattice one mention major deficiencies. It's could be that convenient public-private-key schemes like RSA are just impossible to do in a quantum world. Though to be fair it could also be true classically - their security hasn't been proven.

by cenal 8y ago

sgt101 8y ago

I don't think that there is an encryption crisis because there are post quantum schemes : https://en.wikipedia.org/wiki/Post-quantum_cryptography https://en.wikipedia.org/wiki/Post-quantum_cryptography I think that it is expected that these can / will be brought into use well before QC becomes widely used and therefore attackers will only have the opportunity to decrypt public key traffic that is many years old. Very short keys can already be attacked using GPU clusters, and it is clear QC will be limited in power for a long time, so traffic encrypted with long RSA keys will be safe for many years. Should extremely powerful QC be rapidly available, and should the public key quantum safe stuff be unworkable for some reason (for example very high speed transactions) then Quantum Key Distribution will provide an infrastructure to protect important traffic (financial institutions, markets, defence). The point here is that symmetric keys which are rather hard to break but fast to use can be distributed securely and rapidly and so can be changed very frequently meaning that attackers armed with fantastical QC would still have to spend vast resources to have any chance of reading traffic. I think that the moderate resources being employed today are a good hedge for society dealing with this issue.

throwawaymath 8y ago
> Quantum Key Distribution will provide an infrastructure... No. Quantum key distribution is a fugazzi. It's the red headed step child of actual cryptographic research in the quantum setting. Using quantum key distribution as the basis for a PKI would be ridiculously brittle and over-engineered. Note that the vast majority of interest and research on it comes not from cryptographers, but from physicists who are seeking a cryptographic problem to solve. It's like saying we should abandon the computational complexity theoretic model of cryptography and go back to the information theoretic model. Basically, it's fairy dust sprinkled onto a one time pad. In modern cryptography the one time pad is (approximately) never used because pseudorandomness is sufficient. Key distribution is not a problem which requires quantum computers to solve. Orchestrating a key distribution ceremony using computers that must extraordinarily well calibrated and synchronized using quantum entanglement would be inefficient and asinine, to put it bluntly.
- akvadrako 8y ago
  QKD doesn't actually help with initial key distribution and you wouldn't use it for that anyway, so you are arguing against a straw man. What it does is let you expand your pre-existing shared keys in a provably secure manner. And it might be easy if you use satellites, like the Chinese are doing.
  - throwawaymath 8y ago
    I'm not arguing against a straw man, I'm outlining why it's unnecessary (in very blunt terms). What you've just said does nothing to refute everything I stated. "Provable security" is both rare and unnecessary in most of cryptography (in the information theoretic sense relevant to this discussion, not the sense of e.g. application security or static analysis). To reiterate: you do not need information theoretic security to defend against satcom intrusions. That's tantamount to using a one time pad, which is ridiculously inefficient. The computational model is just fine. Even the United States government only rarely uses information theoretic security these days, and instead opts for the more efficient computational security provided by e.g. AES.
- sgt101 8y ago
  Quantum computers have nothing to do with QKD as far as I know. Instead you need things like this : https://www.toshiba.eu/eu/Cambridge-Research-Laboratory/Quantum-Information/Quantum-Key-Distribution/Toshiba-QKD-system/ https://www.toshiba.eu/eu/Cambridge-Research-Laboratory/Quan... Which detect photon's one at a time (also there is spitting out of photons via lasers) The idea is that you have an infallible alarm for when the optics have been tapped, which means that you can then send lots of symmetric keys and know that they can't be intercepted (provided you are only sending them ~50km. So it's nothing to do with cryptography (really) either - which explains why cryptographers aren't that interested in it. Also it's not a fugazzi as there are several working testbeds in the wild.
  - throwawaymath 8y ago
    A system for providing assurance against tamper detection during key distribution is pretty clearly germane to cryptography. Cryptography already provides very mature solutions for tamper detection. Like I said, information theoretically secure tamper detection is over-engineered and unnecessary.
akvadrako 8y ago
Did you read that wiki page? None of the asymmetric schemes are in widespread use and the blurbs for all except the Lattice one mention major deficiencies. It's could be that convenient public-private-key schemes like RSA are just impossible to do in a quantum world. Though to be fair it could also be true classically - their security hasn't been proven.