4 ms·

This last sentence of the abstract, "This destroyes the RSA cryptosystem", does not appear on the abstract of the actual PDF (which also appears to be dated).

This last sentence of the abstract, "This destroyes the RSA cryptosystem", does not appear on the abstract of the actual PDF (which also appears to be dated). How does it destroy RSA? Under what conditions? That claim sounds rather broad and definitely bold, to say the least.

gpm 6y ago
> work in progress 31.10.2019 ^ Date on the pdf
- elmo2you 6y ago
  Yes, that's what I meant with dated. So the linked paper is a work in progress from half a year ago, but presented today on ePrint and with an abstract that has extra text added. I can not determine if this "discovery" could actually break any practically operating RSA systems. Considering how that is probably true for most people, that could even be the intent here. The claim that this will destroy RSA cryptosystems, so all of them categorically, just feels like a big red flag to me. If it said it could break RSA under certain circumstances .. then maybe. Don't get me wrong, I think there are plenty of things wrong with RSA. Not least of all that determining if a key pair has a backdoor (when only having access to a public key), is essentially just as hard as deriving a private key from a public key (both require you to factor the product of two primes). It still puzzles me that apparently only cryptographic strength has been an argument for the adoption of RSA, but not the ability to detect any (trivially simple to add) backdoor. Apparently we are all supposed to trust whoever generated an RSA key pair (and only supplies a public key). Something I'd rather not do in this day and age.
  - phkahler 6y ago
    You're supposed to generate your own key pair. Keep the private one and publish the public one.
  - jfrunyon 6y ago
    Why would someone backdoor their own key when they could instead just mirror the data or something? Yes, the person you are encrypting something towards is responsible for ensuring that encryption is secure. No matter how secure you make the cryptography, the other party could still just leak the key...
    - elmo2you 6y ago
      > Why would someone backdoor their own key when they could instead just mirror the data or something? Ever thought about .. let say big commercial companies (e.g. social media platforms), using keys that are either knowingly or unknowingly tweaked? A backdoor might not be trivially simple (one of the primes being fixes), but e.g. one prime be somehow part of any collection that is smaller than the pool of truly random primes. The problem then changes into "just" a list of division on the product of primes, with all potential candidates. A third party with the right information would have the practical ability to circumvent the encryption. Still, at the same time, the companies can (maybe even sincerely) claim they use strong cryptography that "can't be broken" (when it has no backdoor). Luckily, no government would ever consider either demanding such things, or covertly implement them through a compromised supply chains (or standard bodies?), even without the knowledge of their targets. [/sarcasm] To be clear, I'm not saying this actually happens. I honestly don't know. There is also something to say that this would already have leaked if it did happen. Maybe. On the other hand, some rather nasty secrets have successfully been kept for a long time. Sometimes decades, or still denied after as much as a century. I'm only saying that it is practically impossible to independently determine if such things are happening, while the technically possibility actually exists. Those involved might themselves not even be aware of it, which makes it even more problematic. Which makes me wonder, why RSA was ever adopted in the first place. I know it all made more sense when it was introduced, in a world with a lot more trust (maybe always naively, considering some historical revelations). But with everything that has happened ever since, the world has changed a lot. > No matter how secure you make the cryptography, the other party could still just leak the key. That's a whole different topic and not what I was pointing at.
      - erincandescent 6y ago

gpm 6y ago

> work in progress 31.10.2019 ^ Date on the pdf

elmo2you 6y ago
Yes, that's what I meant with dated. So the linked paper is a work in progress from half a year ago, but presented today on ePrint and with an abstract that has extra text added. I can not determine if this "discovery" could actually break any practically operating RSA systems. Considering how that is probably true for most people, that could even be the intent here. The claim that this will destroy RSA cryptosystems, so all of them categorically, just feels like a big red flag to me. If it said it could break RSA under certain circumstances .. then maybe. Don't get me wrong, I think there are plenty of things wrong with RSA. Not least of all that determining if a key pair has a backdoor (when only having access to a public key), is essentially just as hard as deriving a private key from a public key (both require you to factor the product of two primes). It still puzzles me that apparently only cryptographic strength has been an argument for the adoption of RSA, but not the ability to detect any (trivially simple to add) backdoor. Apparently we are all supposed to trust whoever generated an RSA key pair (and only supplies a public key). Something I'd rather not do in this day and age.
- phkahler 6y ago
  You're supposed to generate your own key pair. Keep the private one and publish the public one.
- jfrunyon 6y ago
  Why would someone backdoor their own key when they could instead just mirror the data or something? Yes, the person you are encrypting something towards is responsible for ensuring that encryption is secure. No matter how secure you make the cryptography, the other party could still just leak the key...
  - elmo2you 6y ago
    > Why would someone backdoor their own key when they could instead just mirror the data or something? Ever thought about .. let say big commercial companies (e.g. social media platforms), using keys that are either knowingly or unknowingly tweaked? A backdoor might not be trivially simple (one of the primes being fixes), but e.g. one prime be somehow part of any collection that is smaller than the pool of truly random primes. The problem then changes into "just" a list of division on the product of primes, with all potential candidates. A third party with the right information would have the practical ability to circumvent the encryption. Still, at the same time, the companies can (maybe even sincerely) claim they use strong cryptography that "can't be broken" (when it has no backdoor). Luckily, no government would ever consider either demanding such things, or covertly implement them through a compromised supply chains (or standard bodies?), even without the knowledge of their targets. [/sarcasm] To be clear, I'm not saying this actually happens. I honestly don't know. There is also something to say that this would already have leaked if it did happen. Maybe. On the other hand, some rather nasty secrets have successfully been kept for a long time. Sometimes decades, or still denied after as much as a century. I'm only saying that it is practically impossible to independently determine if such things are happening, while the technically possibility actually exists. Those involved might themselves not even be aware of it, which makes it even more problematic. Which makes me wonder, why RSA was ever adopted in the first place. I know it all made more sense when it was introduced, in a world with a lot more trust (maybe always naively, considering some historical revelations). But with everything that has happened ever since, the world has changed a lot. > No matter how secure you make the cryptography, the other party could still just leak the key. That's a whole different topic and not what I was pointing at.
    - erincandescent 6y ago