5 ms·

People also forget that analogue computers, mechanical devices to perform calculations, can also be faster than digital computers in some situations. That does

People also forget that analogue computers, mechanical devices to perform calculations, can also be faster than digital computers in some situations. That doesn't make them commercially viable. Seems to me that most all of the quantum computing community is trying to be in the right place when they can start cracking current encryption standards at a commercial scale. At that moment, anyone with a functional quantum computer will drown in money. Then a few weeks later new quantum-resistant algorithms will appear and the gold rush will end. All the other quantum projects seem like attempts to keep ones foot in the market while waiting for that day.

ahelwer 4y ago
Cracking encryption is basically irrelevant as a quantum computing application. Post-quantum encryption algorithm development proceeds apace and the messaging is already "if you want this to still be encrypted 30 years from now, start using post-quantum encryption today." Anybody caught with their pants down the day quantum computers can actually crack 4096-bit RSA simply isn't serious about security.
- tsunamifury 4y ago
  “Anyone who doesn’t have weaponized anthrax isn’t serious about home defense.” This forum gets more and more detached from reality every day.
  - thadt 4y ago
    Not this forum, but rather the US government: “NSA intends that all NSS will be quantum-resistant by 2035, in accordance with the goal espoused in NSM-10.” Source: https://media.defense.gov/2022/Sep/07/2003071836/-1/-1/0/CSI_CNSA_2.0_FAQ_.PDF https://media.defense.gov/2022/Sep/07/2003071836/-1/-1/0/CSI...
  - ahelwer 4y ago
    The list of things that have to be encrypted 30 years from now is very, very small. I doubt any (many?) people here have contact with any of it. I don't understand your analogy at all, sorry.
    - sandworm101 4y ago
      The message I sent to my girlfriend last night. In 30 years, when I am running for president, that email/text/signal message might come back to haunt me should anyone be able to decrypt the archived/encrypted copies held by state agencies. Anything that is private today is private for a reason. That reason doesn't automatically disappear over time.
      - ahelwer 4y ago
        This is indistinguishable from hoarder logic. Such things straight up don't matter on the scale of decades. The US DOJ has a policy of automatic declassification after 25 years.
        crazygringo 4y ago
        You do realize that because of #metoo, claims and evidence of people's actions 30, 40 years ago are being judged in the court of public opinion, if not in actual courts? I don't think you've been paying attention to the news. Also the US government isn't a great example. JFK was assassinated in 1963 and all records surrounding that still haven't been released. The idea that people don't care about secrets across the span of decades is utterly wrong.
        deleted 4y ago
        [deleted]
        charcircuit 4y ago
        How does encryption impact #metoo? The person waking the accusation would have a decrypted version of the message and even if they didn't they could accuse without proof.
        sandworm101 4y ago
        >> hoarder logic. And the US intelligence community is the greatest data hoarder on the planet, rivaled only perhaps by the combined forces of facebook/google.
  - less_less 4y ago
    It's definitely not true today: for example, there are no NIST standards (and I'm not sure about standards from other governments) for quantum-resistant key exchange. Several such systems have been developed, and NIST has even chosen one to standardize, but they aren't standardized or widely deployed yet. But I expect that in 5-10 years, most security systems designed by competent professionals (up-to-date OS security services, TLS servers, SSH servers, VPN, firmware update systems etc) will have post-quantum crypto enabled by default. And I expect it will take longer than that to build a QC that can break classical crypto. More likely it will play out like the SHA-1 break: all professional security engineers should have switched off SHA-1 (at least for unkeyed hashing) years before any collision was found, and users who apply security patches should therefore by mostly up to date, but I'm sure some are still using the older crypto.
  - deleted 4y ago
    [deleted]
- less_less 4y ago
  Yeah, people who are serious will have probably switched to / hybridized with PQC before a cryptographically relevant quantum computer is built. Unless some state agency has a secret one. So the main relevance might just be forcing everyone to switch / hybridize. At the same time, from history it seems almost certain that, if indeed a CRQC ever gets built, a significant number of users will not have secure PQC rolled out on day 0.
charlieyu1 4y ago
Quantum resistant encryption is already available
- JBits 4y ago
  Would you be able to give any examples of quantum resistant encryption algorithms? I'm not familiar with the field and my most recent knowledge is a post on hn saying that some post quantum candidates had been broken by old laptops.
  - adrianN 4y ago
    https://en.wikipedia.org/wiki/Post-quantum_cryptography https://en.wikipedia.org/wiki/Post-quantum_cryptography
  - GTP 4y ago
    The whole symmetric key cryptography (e.g. AES) ia already quantum resistant. The problem only holds for public key encryption, but as the other commenter pointed out, there are already promising algorithms.
    - JBits 4y ago
      That's nice, I didn't realise AES was quantum resistant. However, an algorithm being promising doesn't mean it works. Do you know how well the development of these other techniques is progressing?
      - GTP 4y ago
        I'm not an expert in the field, but there is already a NIST competition going on to stansardize post-quantum public key ciphers. So I would say that we're at a good point in post-quantum cryptography development.
    - kragen 4y ago
      It's potentially quantum-resistant depending on how it's used. Grover's algorithm still reduces your effective key length by half in many situations.
crazygringo 4y ago
You've got me intrigued -- what are examples of mechanical devices being faster than digital ones? Assuming you're talking man-made. I'm trying to imagine and am totally stumped.
- WorkerBee28474 4y ago
  Fire control computers, like on a navy ship, were faster than digital computers of the day. YouTube has a number of videos on them. An opamp performs multiplication faster than a digital computer (speed of light vs a few cycles). It's not super useful on its own, but it does fit the criteria. In Veritasium's video 2/2 on analog computers [0] they show some startup products near the end. [0]https://youtu.be/GVsUOuSjvcg?t=898 https://youtu.be/GVsUOuSjvcg?t=898
  - gaze 4y ago
    What no. Opamps don’t multiply and they don’t operate at the speed of light. They have some timescale that goes like their bandwidth, which depends on their feedback path.
    - Animats 4y ago
      Yes, feedback op-amps definitely have bandwidth limits. Although you can get ones in the gigahertz range now. Analog multiplier ICs are available.[1] They're not common, and they cost $10-$20 each. Error is about 2% worst case for that one. There are several clever tricks used to multiply. See "Gilbert Cell" and "quarter square multiplier". [1] https://www.digikey.com/en/htmldatasheets/production/1031484/0/0/1/ad633.html https://www.digikey.com/en/htmldatasheets/production/1031484...
    - boltzmann-brain 4y ago
      The propagation time around the feedback loop is still (length of loop) / (speed of light*slowdown constant), so yes, "at the speed of light".
      - 4y ago
kragen 4y ago
Analog computers have mostly been electronic rather than mechanical for 60 years. "Digital" and "electronic" are not synonyms; they are completely orthogonal. Analog computers 60 years ago were mostly built with op-amps rather than shafts and gears, despite the survival of WWII-era mechanical naval fire control computers. That's in large part because human-scale shafts and gears max out with signals in the hertz to kilohertz range, while even the most ordinary op-amps can handle signals in the tens of kilohertz range (which has been true for 100 years) and op-amps in the tens of megahertz range have been available for 60 years. Also, shafts and gears have inherent errors of around 1% from backlash, while op-amps can usually do better than 0.1% (again, for the last 100 years) and by 60 years ago better than 0.001%. So with off-the-shelf electronics an analog computer can compute 1000 times faster with 1000 times better precision than if it were mechanical. Until the 01960s they used vacuum tubes and so used more power and were less reliable; since then electronics have used less power and been more reliable. Today we still use plenty of analog computation, but it's pushed to the margins. Every sound card has an antialiasing analog filter on its front end before switching to the digital domain. Even software-defined radios still use analog electronics to upconvert and downconvert signals between baseband or IF and the RF. Your Wi-Fi card can't sample that 2.4 GHz signal at its 4.8 Gsps Nyquist rate; doing that is not impossible but still requires high-end digital electronics. Submillimeter-wave communication is very much dependent on precise analog signal processing to modulate your desired signal into the hundreds of GHz range. ("Precise" in this case doesn't mean with linearity errors as low as 1%.)

ahelwer 4y ago

Cracking encryption is basically irrelevant as a quantum computing application. Post-quantum encryption algorithm development proceeds apace and the messaging is already "if you want this to still be encrypted 30 years from now, start using post-quantum encryption today." Anybody caught with their pants down the day quantum computers can actually crack 4096-bit RSA simply isn't serious about security.

tsunamifury 4y ago
“Anyone who doesn’t have weaponized anthrax isn’t serious about home defense.” This forum gets more and more detached from reality every day.
- thadt 4y ago
  Not this forum, but rather the US government: “NSA intends that all NSS will be quantum-resistant by 2035, in accordance with the goal espoused in NSM-10.” Source: https://media.defense.gov/2022/Sep/07/2003071836/-1/-1/0/CSI_CNSA_2.0_FAQ_.PDF https://media.defense.gov/2022/Sep/07/2003071836/-1/-1/0/CSI...
- ahelwer 4y ago
  The list of things that have to be encrypted 30 years from now is very, very small. I doubt any (many?) people here have contact with any of it. I don't understand your analogy at all, sorry.
  - sandworm101 4y ago
    The message I sent to my girlfriend last night. In 30 years, when I am running for president, that email/text/signal message might come back to haunt me should anyone be able to decrypt the archived/encrypted copies held by state agencies. Anything that is private today is private for a reason. That reason doesn't automatically disappear over time.
    - ahelwer 4y ago
      This is indistinguishable from hoarder logic. Such things straight up don't matter on the scale of decades. The US DOJ has a policy of automatic declassification after 25 years.
      - crazygringo 4y ago
        You do realize that because of #metoo, claims and evidence of people's actions 30, 40 years ago are being judged in the court of public opinion, if not in actual courts? I don't think you've been paying attention to the news. Also the US government isn't a great example. JFK was assassinated in 1963 and all records surrounding that still haven't been released. The idea that people don't care about secrets across the span of decades is utterly wrong.
        deleted 4y ago
        [deleted]
        charcircuit 4y ago
        How does encryption impact #metoo? The person waking the accusation would have a decrypted version of the message and even if they didn't they could accuse without proof.
      - sandworm101 4y ago
        >> hoarder logic. And the US intelligence community is the greatest data hoarder on the planet, rivaled only perhaps by the combined forces of facebook/google.
- less_less 4y ago
  It's definitely not true today: for example, there are no NIST standards (and I'm not sure about standards from other governments) for quantum-resistant key exchange. Several such systems have been developed, and NIST has even chosen one to standardize, but they aren't standardized or widely deployed yet. But I expect that in 5-10 years, most security systems designed by competent professionals (up-to-date OS security services, TLS servers, SSH servers, VPN, firmware update systems etc) will have post-quantum crypto enabled by default. And I expect it will take longer than that to build a QC that can break classical crypto. More likely it will play out like the SHA-1 break: all professional security engineers should have switched off SHA-1 (at least for unkeyed hashing) years before any collision was found, and users who apply security patches should therefore by mostly up to date, but I'm sure some are still using the older crypto.
- deleted 4y ago
  [deleted]
less_less 4y ago
Yeah, people who are serious will have probably switched to / hybridized with PQC before a cryptographically relevant quantum computer is built. Unless some state agency has a secret one. So the main relevance might just be forcing everyone to switch / hybridize. At the same time, from history it seems almost certain that, if indeed a CRQC ever gets built, a significant number of users will not have secure PQC rolled out on day 0.

charlieyu1 4y ago

Quantum resistant encryption is already available

JBits 4y ago
Would you be able to give any examples of quantum resistant encryption algorithms? I'm not familiar with the field and my most recent knowledge is a post on hn saying that some post quantum candidates had been broken by old laptops.
- adrianN 4y ago
  https://en.wikipedia.org/wiki/Post-quantum_cryptography https://en.wikipedia.org/wiki/Post-quantum_cryptography
- GTP 4y ago
  The whole symmetric key cryptography (e.g. AES) ia already quantum resistant. The problem only holds for public key encryption, but as the other commenter pointed out, there are already promising algorithms.
  - JBits 4y ago
    That's nice, I didn't realise AES was quantum resistant. However, an algorithm being promising doesn't mean it works. Do you know how well the development of these other techniques is progressing?
    - GTP 4y ago
      I'm not an expert in the field, but there is already a NIST competition going on to stansardize post-quantum public key ciphers. So I would say that we're at a good point in post-quantum cryptography development.
  - kragen 4y ago
    It's potentially quantum-resistant depending on how it's used. Grover's algorithm still reduces your effective key length by half in many situations.

crazygringo 4y ago

You've got me intrigued -- what are examples of mechanical devices being faster than digital ones? Assuming you're talking man-made. I'm trying to imagine and am totally stumped.

WorkerBee28474 4y ago
Fire control computers, like on a navy ship, were faster than digital computers of the day. YouTube has a number of videos on them. An opamp performs multiplication faster than a digital computer (speed of light vs a few cycles). It's not super useful on its own, but it does fit the criteria. In Veritasium's video 2/2 on analog computers [0] they show some startup products near the end. [0]https://youtu.be/GVsUOuSjvcg?t=898 https://youtu.be/GVsUOuSjvcg?t=898
- gaze 4y ago
  What no. Opamps don’t multiply and they don’t operate at the speed of light. They have some timescale that goes like their bandwidth, which depends on their feedback path.
  - Animats 4y ago
    Yes, feedback op-amps definitely have bandwidth limits. Although you can get ones in the gigahertz range now. Analog multiplier ICs are available.[1] They're not common, and they cost $10-$20 each. Error is about 2% worst case for that one. There are several clever tricks used to multiply. See "Gilbert Cell" and "quarter square multiplier". [1] https://www.digikey.com/en/htmldatasheets/production/1031484/0/0/1/ad633.html https://www.digikey.com/en/htmldatasheets/production/1031484...
  - boltzmann-brain 4y ago
    The propagation time around the feedback loop is still (length of loop) / (speed of light*slowdown constant), so yes, "at the speed of light".
    - 4y ago

kragen 4y ago

Analog computers have mostly been electronic rather than mechanical for 60 years. "Digital" and "electronic" are not synonyms; they are completely orthogonal. Analog computers 60 years ago were mostly built with op-amps rather than shafts and gears, despite the survival of WWII-era mechanical naval fire control computers. That's in large part because human-scale shafts and gears max out with signals in the hertz to kilohertz range, while even the most ordinary op-amps can handle signals in the tens of kilohertz range (which has been true for 100 years) and op-amps in the tens of megahertz range have been available for 60 years. Also, shafts and gears have inherent errors of around 1% from backlash, while op-amps can usually do better than 0.1% (again, for the last 100 years) and by 60 years ago better than 0.001%. So with off-the-shelf electronics an analog computer can compute 1000 times faster with 1000 times better precision than if it were mechanical. Until the 01960s they used vacuum tubes and so used more power and were less reliable; since then electronics have used less power and been more reliable. Today we still use plenty of analog computation, but it's pushed to the margins. Every sound card has an antialiasing analog filter on its front end before switching to the digital domain. Even software-defined radios still use analog electronics to upconvert and downconvert signals between baseband or IF and the RF. Your Wi-Fi card can't sample that 2.4 GHz signal at its 4.8 Gsps Nyquist rate; doing that is not impossible but still requires high-end digital electronics. Submillimeter-wave communication is very much dependent on precise analog signal processing to modulate your desired signal into the hundreds of GHz range. ("Precise" in this case doesn't mean with linearity errors as low as 1%.)