51–60 of 72 posts
I could be wrong (my physics background isn't that strong either) but I think Dyson's "time without end" paper http://www.aleph.se/Trans/Global/Omega/dyson.txt shows that eventually the universe will cool down enough to make all keys brute-force-attackable despite Bremermann's limit. Given a finite amount of attacker computation you're willing to defend against, you can get a real advantage from key stretching (thoug…
Technically bcrypt isn't a KDF.
Earlier quoted context omitted.
Technically bcrypt isn't a KDF.
Hmm, isn't it?
Earlier quoted context omitted.
Hmm, isn't it?
It isn't. You cannot derive an arbitrary length key with bcrypt.
Earlier quoted context omitted.
If you wait for the temperature to drop, and the universe is expanding, distant galaxies will recede to the point that they are now moving away faster than the speed of light and their matter is no longer available to contribute.
Thank it is expanding now really means that it will expand forever? Are there not other physics at play that could stop that at some point, yeah I don't know much about any of this just wondering out loud.
Obviously it can't be ruled at that at some point this would stop and/or reverse. But there's no reason to think so, and if we're considering arbitrary future changes then we may as well consider that the universe might suddenly start heating up again in the future, or more mass will start appearing out of nowhere. Or god appears and hands out free decryption keys to everyone.
I can't say I understood and evaluated all the physics here (I skimmed parts) but I was pretty surprised by how small the estimate was. I would've assumed that, were we to have one or two thousand years more cryptographic history, we'd end up using ginormous keys (maybe on the order of 1 MiB?). But this suggests that 512 or 1024 bits might be all we need.
This is because exponential growth is counter-intuitive. A 256 bit key is not 2x more secure than 128 bit, it is 340282366920938463463374607431768211456x more secure.
I can't say I understood and evaluated all the physics here (I skimmed parts) but I was pretty surprised by how small the estimate was. I would've assumed that, were we to have one or two thousand years more cryptographic history, we'd end up using ginormous keys (maybe on the order of 1 MiB?). But this suggests that 512 or 1024 bits might be all we need.
That assumes that the best you can do is brute force, but real encryption algorithms (even AES) are weaker than that, so the attacker can infer some bits of the key. More so for asymmetric encryption.
> "Don't talk about the future," Vidyasagar says.
> "What? Why not?"
> "Look at this computer," Vidyasagar says, gesturing at the mainframe. "Computers are getting more powerful, yes?"
> "Sure."
> "What is the most powerful computer that will be built? Ever. Not this year. Not this decade. What computer will be the most powerful? And how powerful will it be? And how big?"
> Hatt thinks on this for ten long seconds. He opens his mouth, but never actually forms a word. The scale of the question is beyond him.
> Vidyasagar says to him, "No matter what you say, you will look like a fool. Every statement about the future turns out to be foolish."
The premise reminds of discussions of computing in Ra. https://qntm.org/aum > "Don't talk about the future," Vidyasagar says. > "What? Why not?" > "Look at this computer," Vidyasagar says, gesturing at the mainframe. "Computers are getting more powerful, yes?" > "Sure." > "What is the most powerful computer that will be built? Ever. Not this year. Not this decade. What computer will be the most powerful? And how powe…
Is this proof that the universe cannot understand itself? It seems weird that there can be a set of information in the universe that can be hidden from the rest of the universe.