9 ms·

This is a non-issue IMO. Contrary to popular belief QCs are not magical oracles that can do arbitrary exponential calculations in polynomial time. Instead QCs c

by air7 8y ago

This is a non-issue IMO. Contrary to popular belief QCs are not magical oracles that can do arbitrary exponential calculations in polynomial time. Instead QCs can do only very specific things better than conventional computers and there are a surprisingly low number of known algorithms for QCs even though people have been looking. While it's true that Shor's algorithm allows a QC to potentially factor integers in polynomial time breaking RSA, there are other popular encryption schemes with no known quantum weaknesses and there's a whole field called Post-Quantum Cryptography looking at this property explicitly. And just like upgrading SSL 3.0->TLS 1.1->TLS 1.2->TLS 1.3 was done due to discovered weaknesses yet mostly transparently and with no Y2Kish hype of "the internet is broken", so will we upgrade to quantum resistant algorithms if and when QCs become a reality.

hannob 8y ago
> This is a non-issue IMO. vs. > will we upgrade to quantum resistant algorithms if and when QCs become a reality. Sorry, I don't think your words make sense.
- tptacek 8y ago
  I know you know what you're talking about but I don't understand what you're trying to say here.
  - WilliamEdward 8y ago
    I think they're trying to say OP made a contradiction. On one hand, they think its a non-issue, yet on the other hand they admit that when quantum becomes an every day reality we will have to change everything.
    - maxxxxx 8y ago
      I think the theory is that at the time QC is starting to threaten current encryption there will be new algorithms available and the transition will be not difficult. Seems pretty likely.
atq2119 8y ago
You probably mean well, but this is dangerous misinformation. There are no popular public-key encryption schemes that are safe against quantum computing. The only popular public-key encryption schemes are based on RSA and ECC, both of which are broken by variants of Shor's algorithm. Yes, popular symmetric cryptography is safe to the best of our knowledge, but that doesn't help much since virtually all symmetric crypto that is actually applicable at scale relies on some initial public-key crypto for bootstrapping. And yes, there's research into post-quantum public-key cryptography, but it's pretty underwhelming so far. It seems possible, but at a horrible loss of performance (keys are sized on the order of kilobytes or more, as opposed to 32 bytes for ECC). I'm pretty pessimistic about the consequences of quantum computing, to be honest.
- alfiedotwtf 8y ago
  Not sure why you're greyed out (hopefully not because you're being downvoted) because you're absolutely right - all asymmetric cryptography we have right now will be broken. On the other hand... I doubt we'll have working quantum computers for at least the next 500 years.
  - WilliamEdward 8y ago
    500 years is a big leap but I appreciate the caution. We actually already do have working quantum computers. If you mean personal quantum computers, commercially, I would give it about a century, give or take a decade.
    - alfiedotwtf 8y ago
      No. I'm talking about quantum computers that are actually practical. Running stable at 0.004K for only a few milliseconds in a lab is not practical.
    - AlexCoventry 8y ago
      "Working" in this context clearly means "able to break deployed cryptosystems." We are a long way from that. https://www.forbes.com/sites/fredcampbell/2018/03/14/how-capable-is-googles-bristlecone-quantum-processor/#32f012f01775 https://www.forbes.com/sites/fredcampbell/2018/03/14/how-cap...
WilliamEdward 8y ago
There's always someone in these threads who thinks they are blessing people with knowledge that QCs are not as powerful and amazing as people think. While it's certainly a revelation to know that, it doesn't tell the full story. QCs are still able to perform those specific tasks really well, and we haven't even begun to get our hands on a personal quantum computer which will ultimately give rise to more algorithms and general discoveries about them. It's not like the internet is done when QCs come into play, but there's always someone who thinks they have an unpopular opinion about the power of quantum computers when in reality both sides are usually biased or misinformed.
wefarrell 8y ago
I imagine that state intelligence agencies are logging all encrypted communication today in the hopes that it will be much easier to decrypt them at some point in the future. That’s terrifying.
- BenjiWiebe 8y ago
  Good thing they don't have infinite storage space.
  - maxxxxx 8y ago
    For a lot of purposes they have close to infinite space. You can record a lot of data for a pretty reasonable price.
    - true_tuna 8y ago
      Yeah, I was working in cutting edge storage a while ago and heard the biggest customers were Facebook and “a three letter acronym we can’t talk about”. This sort of infrastructure might be cool to work on, were it not for the fact that it violates the constitution and is counter to the public good.
      - thewizardofaus 8y ago
        Why does KFC need so much storage ?! /s
- DenisM 8y ago
  PFS should put your mind at ease. https://en.m.wikipedia.org/wiki/Forward_secrecy https://en.m.wikipedia.org/wiki/Forward_secrecy
  - jwilk 8y ago
    The algorithms commonly used to implement forward secrecy (DH, ECDH) are not quantum-resitant.

by air7 8y ago

hannob 8y ago

> This is a non-issue IMO. vs. > will we upgrade to quantum resistant algorithms if and when QCs become a reality. Sorry, I don't think your words make sense.

tptacek 8y ago
I know you know what you're talking about but I don't understand what you're trying to say here.
- WilliamEdward 8y ago
  I think they're trying to say OP made a contradiction. On one hand, they think its a non-issue, yet on the other hand they admit that when quantum becomes an every day reality we will have to change everything.
  - maxxxxx 8y ago
    I think the theory is that at the time QC is starting to threaten current encryption there will be new algorithms available and the transition will be not difficult. Seems pretty likely.

atq2119 8y ago

You probably mean well, but this is dangerous misinformation. There are no popular public-key encryption schemes that are safe against quantum computing. The only popular public-key encryption schemes are based on RSA and ECC, both of which are broken by variants of Shor's algorithm. Yes, popular symmetric cryptography is safe to the best of our knowledge, but that doesn't help much since virtually all symmetric crypto that is actually applicable at scale relies on some initial public-key crypto for bootstrapping. And yes, there's research into post-quantum public-key cryptography, but it's pretty underwhelming so far. It seems possible, but at a horrible loss of performance (keys are sized on the order of kilobytes or more, as opposed to 32 bytes for ECC). I'm pretty pessimistic about the consequences of quantum computing, to be honest.

alfiedotwtf 8y ago
Not sure why you're greyed out (hopefully not because you're being downvoted) because you're absolutely right - all asymmetric cryptography we have right now will be broken. On the other hand... I doubt we'll have working quantum computers for at least the next 500 years.
- WilliamEdward 8y ago
  500 years is a big leap but I appreciate the caution. We actually already do have working quantum computers. If you mean personal quantum computers, commercially, I would give it about a century, give or take a decade.
  - alfiedotwtf 8y ago
    No. I'm talking about quantum computers that are actually practical. Running stable at 0.004K for only a few milliseconds in a lab is not practical.
  - AlexCoventry 8y ago
    "Working" in this context clearly means "able to break deployed cryptosystems." We are a long way from that. https://www.forbes.com/sites/fredcampbell/2018/03/14/how-capable-is-googles-bristlecone-quantum-processor/#32f012f01775 https://www.forbes.com/sites/fredcampbell/2018/03/14/how-cap...

WilliamEdward 8y ago

There's always someone in these threads who thinks they are blessing people with knowledge that QCs are not as powerful and amazing as people think. While it's certainly a revelation to know that, it doesn't tell the full story. QCs are still able to perform those specific tasks really well, and we haven't even begun to get our hands on a personal quantum computer which will ultimately give rise to more algorithms and general discoveries about them. It's not like the internet is done when QCs come into play, but there's always someone who thinks they have an unpopular opinion about the power of quantum computers when in reality both sides are usually biased or misinformed.

wefarrell 8y ago

I imagine that state intelligence agencies are logging all encrypted communication today in the hopes that it will be much easier to decrypt them at some point in the future. That’s terrifying.

BenjiWiebe 8y ago
Good thing they don't have infinite storage space.
- maxxxxx 8y ago
  For a lot of purposes they have close to infinite space. You can record a lot of data for a pretty reasonable price.
  - true_tuna 8y ago
    Yeah, I was working in cutting edge storage a while ago and heard the biggest customers were Facebook and “a three letter acronym we can’t talk about”. This sort of infrastructure might be cool to work on, were it not for the fact that it violates the constitution and is counter to the public good.
    - thewizardofaus 8y ago
      Why does KFC need so much storage ?! /s
DenisM 8y ago
PFS should put your mind at ease. https://en.m.wikipedia.org/wiki/Forward_secrecy https://en.m.wikipedia.org/wiki/Forward_secrecy
- jwilk 8y ago
  The algorithms commonly used to implement forward secrecy (DH, ECDH) are not quantum-resitant.