Because it lowers the threshold for a total informational compromise attack from "exfiltrate 34PB of data from secure govt infrastructure" down to "exfiltrate 100KB of key material". You can get that out over a few days just by pulsing any LED visible from outside an air-gapped facility.
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 Let me say that differently: for all we know, ALL currently available cryptosystems can be easily cracked by some unpublished techniques.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.
> 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.
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).
Why not?
Because it lowers the threshold for a total informational compromise attack from "exfiltrate 34PB of data from secure govt infrastructure" down to "exfiltrate 100KB of key material". You can get that out over a few days just by pulsing any LED visible from outside an air-gapped facility.
Wait what?
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On which TV show?
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.
> 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.
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).
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One-time pad is provable secure. But it is not useful for backups, of course.
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Thank you for writing this post. This should be the top comment. This is a state actors game, the rules are different.
> could still be valuable to an adversary after decades
What kind of information might be valuable after so long?