4 ms·

As of today, there's no way to prove the security of any available cryptosystem. Let me say that differently: for all we know, ALL currently available cryptosys

As of today, there's no way to prove the security of any available cryptosystem. Let me say that differently: for all we know, ALL currently available cryptosystems can be easily cracked by some unpublished techniques. The only sort-of exception to that requires quantum communication, which is nowhere near practicability on the scale required. The only evidence we have that the cryptography that we commonly use is actually safe is that it's based on "hard" math problems that have been studied for decades or longer by mathematicians without anyone being able to crack them. On the other hand, some popular cryptosystems that were more common in the past have been significantly weakened over the years by mathematical advances. Those were also based on math problems that were believed to be "hard." (They're still very hard actually, but less so than we thought.) What I'm getting at is that if you have some extremely sensitive data that could still be valuable to an adversary after decades, you know, the type of stuff the government of a developed nation might be holding, you probably shouldn't let it get into the hands of an adversarial nation-state even encrypted.

yard2010 1y ago
Thank you for writing this post. This should be the top comment. This is a state actors game, the rules are different.
Intermernet 1y ago
While I understand what you're saying, you can extend this logic to such things as faster-than-light travel, over-unity devices, time travel etc. They're just "hard" math problems. The current state of encryption is based on math problems many levels harder than the ones that existed a few decades ago. Most vulnerabilities have been due to implementation bugs, and not actual math bugs. Probably the highest profile "actual math" bug is the DUAL_EC_DRBG weakness which was (almost certainly) deliberately inserted by the NSA, and triggered a wave of distrust in not just NIST, but any committee designed encryption standards. This is why people prefer to trust DJB than NIST. There are enough qualified eyes on most modern open encryption standards that I'd trust them to be as strong as any other assumptions we base huge infrastructure on. Tensile strengths of materials, force of gravity, resistance and heat output of conductive materials, etc, etc. The material risk to South Korea was almost certainly orders of magnitude greater by not having encrypted backups, than by having encrypted backups, no matter where they were stored (as long as they weren't in the same physical location, obviously).
- famouswaffles 1y ago
  >While I understand what you're saying, you can extend this logic to such things as faster-than-light travel, over-unity devices, time travel etc. They're just "hard" math problems. No you can't. Those aren't hard math problems. They're Universe breaking assertions. This is not the problem of flight. They're not engineering problems. They're not, "perhaps in the future, we'll figure out..". Unless our understanding of physics is completely wrong, then None of those things are ever going to happen.
  - Intermernet 1y ago
    According to our understanding of physics, which is based on our understanding of maths, the time taken to brute force a modern encryption standard, even with quantum computers, is longer than the expected life of the universe. The likely-hood of "finding a shortcut" to do this is in the same ball-park as "finding a shortcut" to tap into ZPE or "vacuum energy" or create worm-holes. The maths is understood, and no future theoretical advances can change that. It would involve completely new maths to break these. We passed the "if only computers were a few orders of magnitude faster it's feasible" a decade or more ago.
    - WCSTombs 1y ago
      Sorry, I don't think this is true. There is basically no useful proven lower bound on the complexity of breaking popular cryptosystems. The math is absolutely not understood. In fact, it is one of the most poorly understood areas of mathematics. Consider that breaking any classical cryptosystem is in the complexity class NP, since if an oracle gives you the decryption key, you can break it quickly. Well we can't even prove that NP != P, i.e., that there even exists a problem where having such an oracle gives you a real advantage. Actually, we can't even prove that PSPACE != P, which should be way easier than proving NP != P if it's true.
ants_everywhere 1y ago
> The only evidence we have that the cryptography that we commonly use is actually safe is that it's based on "hard" math problems that have been studied for decades or longer by mathematicians without anyone being able to crack them. Adding to this... Most crypto I'm aware of implicitly or explicitly assumes P != NP. That's the right practical assumption, but it's still an major open math problem. If P = NP then essentially all crypto can be broken with classical (i.e. non-quantum) computers. I'm not saying that's a practical threat. But it is a "known unknown" that you should assign a probability to in your risk calculus if you're a state thinking about handing over the entirety of your encrypted backups to a potential adversary. Most of us just want to establish a TLS session or SSH into some machines.
blacklion 1y ago
One-time pad is provable secure. But it is not useful for backups, of course.
- kmoser 1y ago
  Even OTP is not secure if others have access to it.
  - IAmBroom 1y ago
    Every castle wall can be broken with money.
    - otterley 1y ago
      How much money is required to decrypt a file encrypted with a 256-bit AES key?
      - blacklion 1y ago
        How much person(s) who know the key will take to change country and don't work anymore? Or how much it is cost to kidnap significant one of key bearer(s)? I think, it is very reasonable sums for governments of almost any country.
        otterley 1y ago
        I think you assume that encryption keys are held by people like a house key in their pocket. That's not the case for organizations who are security obsessed. They put their keys in HSMs. They practice defense in depth. They build least-privilege access controls.
- thyristan 1y ago
  OTP can be useful especially for backups. Use a fast random number generator (real, not pseudo), write output to fill tape A. XOR the contents of tape A to your backup datastream and write result to Tape B. Store tape A and B in different locations.
Chris2048 1y ago
> could still be valuable to an adversary after decades What kind of information might be valuable after so long?

yard2010 1y ago

Thank you for writing this post. This should be the top comment. This is a state actors game, the rules are different.

Intermernet 1y ago

While I understand what you're saying, you can extend this logic to such things as faster-than-light travel, over-unity devices, time travel etc. They're just "hard" math problems. The current state of encryption is based on math problems many levels harder than the ones that existed a few decades ago. Most vulnerabilities have been due to implementation bugs, and not actual math bugs. Probably the highest profile "actual math" bug is the DUAL_EC_DRBG weakness which was (almost certainly) deliberately inserted by the NSA, and triggered a wave of distrust in not just NIST, but any committee designed encryption standards. This is why people prefer to trust DJB than NIST. There are enough qualified eyes on most modern open encryption standards that I'd trust them to be as strong as any other assumptions we base huge infrastructure on. Tensile strengths of materials, force of gravity, resistance and heat output of conductive materials, etc, etc. The material risk to South Korea was almost certainly orders of magnitude greater by not having encrypted backups, than by having encrypted backups, no matter where they were stored (as long as they weren't in the same physical location, obviously).

famouswaffles 1y ago
>While I understand what you're saying, you can extend this logic to such things as faster-than-light travel, over-unity devices, time travel etc. They're just "hard" math problems. No you can't. Those aren't hard math problems. They're Universe breaking assertions. This is not the problem of flight. They're not engineering problems. They're not, "perhaps in the future, we'll figure out..". Unless our understanding of physics is completely wrong, then None of those things are ever going to happen.
- Intermernet 1y ago
  According to our understanding of physics, which is based on our understanding of maths, the time taken to brute force a modern encryption standard, even with quantum computers, is longer than the expected life of the universe. The likely-hood of "finding a shortcut" to do this is in the same ball-park as "finding a shortcut" to tap into ZPE or "vacuum energy" or create worm-holes. The maths is understood, and no future theoretical advances can change that. It would involve completely new maths to break these. We passed the "if only computers were a few orders of magnitude faster it's feasible" a decade or more ago.
  - WCSTombs 1y ago
    Sorry, I don't think this is true. There is basically no useful proven lower bound on the complexity of breaking popular cryptosystems. The math is absolutely not understood. In fact, it is one of the most poorly understood areas of mathematics. Consider that breaking any classical cryptosystem is in the complexity class NP, since if an oracle gives you the decryption key, you can break it quickly. Well we can't even prove that NP != P, i.e., that there even exists a problem where having such an oracle gives you a real advantage. Actually, we can't even prove that PSPACE != P, which should be way easier than proving NP != P if it's true.

ants_everywhere 1y ago

> The only evidence we have that the cryptography that we commonly use is actually safe is that it's based on "hard" math problems that have been studied for decades or longer by mathematicians without anyone being able to crack them. Adding to this... Most crypto I'm aware of implicitly or explicitly assumes P != NP. That's the right practical assumption, but it's still an major open math problem. If P = NP then essentially all crypto can be broken with classical (i.e. non-quantum) computers. I'm not saying that's a practical threat. But it is a "known unknown" that you should assign a probability to in your risk calculus if you're a state thinking about handing over the entirety of your encrypted backups to a potential adversary. Most of us just want to establish a TLS session or SSH into some machines.

blacklion 1y ago

One-time pad is provable secure. But it is not useful for backups, of course.

kmoser 1y ago
Even OTP is not secure if others have access to it.
- IAmBroom 1y ago
  Every castle wall can be broken with money.
  - otterley 1y ago
    How much money is required to decrypt a file encrypted with a 256-bit AES key?
    - blacklion 1y ago
      How much person(s) who know the key will take to change country and don't work anymore? Or how much it is cost to kidnap significant one of key bearer(s)? I think, it is very reasonable sums for governments of almost any country.
      - otterley 1y ago
        I think you assume that encryption keys are held by people like a house key in their pocket. That's not the case for organizations who are security obsessed. They put their keys in HSMs. They practice defense in depth. They build least-privilege access controls.
thyristan 1y ago
OTP can be useful especially for backups. Use a fast random number generator (real, not pseudo), write output to fill tape A. XOR the contents of tape A to your backup datastream and write result to Tape B. Store tape A and B in different locations.

Chris2048 1y ago

> could still be valuable to an adversary after decades What kind of information might be valuable after so long?