What if someone were to generate keypairs randomly while simultaneously scanning the blockchain for any addresses generated that have previous inputs? How unlikely is it to generate a 'used' address?
If you run 1 billion computers that are each generating and checking the balance of 1 billion addresses per second, you would (at best) have a 1% chance of finding a 'used' address in about 2,190,476 years.
(...)
4.6 X 10
20 divided by 2.1X10
14 = 2,190,476 years.
Hello,
Your math is not accurate.
While I'm willing to accept that I may have made an error in my maths, you didn't point out any errors at all. Please explain why you think my math is not accurate and where you believe I made the mistake.
Hello Danny and hello all,
I say your math is not accurate, and also I cannot fully agree with calculation made by David Perry.
I guess no one can calculate it accurately.
Reason is simple - your math is accurate with specific assumptions. But your assumptions may vary depends on a situation.
There really isn't. Sure you could say that there is a non-zero mathematically calculated probability, but that probability is so low that we humans would generally use the words "impossible" and "there isn't a real chance" to describe it.
Do you know what was "impossible" in 1886?
As you already wrote "there is a non-zero mathematically calculated probability".
And I agree that it's (almost) "impossible".
Imagine a situation. Year 2025 - Bitcoin is still around and everyone loves it.
You don't know how fast the GPU and CPU will be in 10 years. Moore's law is not perfect as you know.
Let say that some evil genius built a botnet, botnet made from 100 000 000 of users. Possible, why not.
He will be able to generate such amount of addresses which we cannot imagine - per second.
Still, his chances are close to "none". But will you still say the, that this is impossible?
And yet the article you linked to specifically says the following:
(...)
Did you even read that document before trying to use it as evidence that "RIPEMD-160 collision can happen"?
Yes, I did. I sent you a link because it's very interesting and it's bringing more infos about what we are talking about.
I didn't used it as a evidence. I used it as a good thing to read if we talk about RIPEMD160.
I don't need the evidence that collision "is possible to" happen one day.
Simple math is telling me that it "can" happen.
I said that your math is not accurate, because simple Radeon GPU card can generate more than 20 million addresses per second.
And my math was based on 1 BILLION computers all running
1 BILLION addresses per second.
How does a 20 million address GPU card make my math incorrect?
It's hard to say how many addresses you can generate with super powerful computer. We can put any number as a variable... because we can make 20 million, 20 billion, more more ...
So that's making those calculations not really accurate.
Still - is it possible to generate same address - address which is already in use by other Bitcoiner and have some founds on it? Yes. It's possible.
You keep saying this, and you keep saying that my math is incorrect, but you haven't provided any evidence yet of either of your statements being true.
I keep saying that... From theoretical point of view, collision is possible.
Your math is not accurate because at least one variable may change depends from a situation.
It's a great graphic. Did you read it? It specifically states:
"brute-force attacks against 256 bit keys will be infeasible
until computers are built from something other than matter and occupy something other than space"
Of course, I'm not sure why you even posted a link to that image since we are discussing a 160 bit hash and not a 256 bit key.
This graphic makes it easier to imagine what sort of a number we are talking about.
It's really a pretty simple calculation. Why do you say it's "hard"? I think any high school student should be capable of it (and probably many primary school students).
If it's so simple, why your calculation is not accurate?
Let me ask some primary school student to teach you
This kind of a calculation is as accurate as carbon dating. So it's not accurate. And cannot be. Or maybe you can calculate how many addresses we can generate per second? How can you do that? You cannot. So it's not accurate.
Best regards.
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