Topic: Accidentally created a wallet address that someone else already has? - page 3. (Read 4257 times)

What makes these more interesting, though, is that we're using computers to generate random numbers. They are actually pseudo-random, as there's no way for a computer to do a truly random number. And then we look at things like the RNG that was in (what was it, Android?) that was exploited... it makes me think that things are still possible and just haven't been discovered yet.

I don't pretend to understand the intricacies of the numbers we are discussing, but like with almost any threat the currency can evolve to protect itself. I do find these threads to be educational though. 

I've always found that an example is the best way to convey the sheer size of numbers. I'll just leave this here:

People keep asking this question over and over again and people here keep answering it. Most of the time it's a wasted effort when they could just link to past answers. But sometimes questions like these lead to interesting threads. This thread is not one one of those but here is an example of one:

https://bitcointalk.org/index.php?topic=604002.20

Most people have a hard time understanding how big a large number actually is. But trust me even if a billion users generate a million addresses each we wouldn't even have used a percentage if all available addresses, not even close.

10^44 is a billion times a billion times a billion times a billion times a million times hundred.

That's a pretty large number indeed.

So considering a population of 10 billion (current population of the world is just over 7 billion including poor people and children) and everyone has a million adress we would only need to use 1*10^-26% of the avialable addresses or in other words 0,0000000000000000000000001% (I may have missed a zero or two, but you hopefully get the idea)

Also note that if we break bitcoin into the smallest units possible with the current protocol (satoshies) and we generate 1 adress for each satoshi we would need 21000000 times 10000000 addresses (all the other addresses would be empty because there would simply not be any more satoshies left). That's 2.1 *10^15 addresses or just 2.1*10^-27%

If in this case you wanted to steal a satoshi (and note you'd only win a single satoshi!) you would have a chance of approximately 1 in 47619047619047621434313142608 of finding the right adress. Even if somehow you have an insanely fast computer that can make 1000 trillion calculations a second (I don't believe such computers even exists yet) you'd still need 1.5 million years to find an address with a satoshi on it.

If you have such a computer you're much much better off mining.

In other words the number of addresses possible might as well be infinite.

1) the chances of that happening are really really small, so it's safe to assume it will never happen

2) no matter online or offline, an address is never registered. When you create an address you create a private key, and from the private key your computer finds the public key (this is an easy thing to do, however it's impossible to calculate the private key from the public key). When you computer finds a private key it would be meaningless to register it because it would be unsafe if there was a large online database storing all known active private keys. And the fact that there is basically an unlimited amount of private keys in the first place.

Read this: http://codinginmysleep.com/stealing-bitcoins-the-hardest-way/

Lets say you build a super ASIC on 12nm (4 generations ahead of current tech) process that could create, validate, and steal one trillion key pairs per second (1 TK/s). That would be about 50,000x more powerful than faster GPU’s today. Lets also say you built a thousand of them and ran them continually with no downtime 24/7/365. In 1 year you could brute force 3*10^28 possible addresses.
If there are 1 quadrillion funded addresses you would still have a ~1% chance of colliding with a random funded address in the next 1,000 years.
Comparatively speaking, your odds of being struck by lightning are about 1 in 280,000, so you’re about 500,000,000,000,000,000,000 times more likely to be struck by lightning than to find an address within the first year. Since that’s also a big number, the odds are equivalent to being struck by lightning about 4.6 times in your lifetime

People don't understand the magnitude of these numbers. If 10 billion people (more than are currently alive) had 1 million addresses each, that would still be only 10¹⁶ addresses in use, or 1/10³² of all addresses. Even if all the miners in the world (currently 75x10¹⁵ H/s) decided to brute force addresses, they would only find 1 every few million years on average.

Then it will take 10⁴⁵ days to check all possible addresses. That's more than 10⁴¹ centuries, or more than 10³³ times as long as the universe has existed.



Ok, a few hundred thousand per day?  That will reduce the time from 10⁴⁵ days to a bit more than 10⁴³ days.  So now we are looking at 10³⁹ centuries, or more than 10³¹ times as long as the universe has existed.


No, this still is not a threat.  Human beings have such a difficulty number with comprehension when it comes to really big numbers.  Perhaps you missed the part where I said:

My understanding is that if it ever became an issue, it would somehow be altered to fix it. Bitcoin is still in its infancy; if there are any risks, I'm sure someone will find a way to make them obsolete again.

That program that creates wallets and check the Balance.. I don't buy the fact that it's not a threat to Security. At least in the future. What if Bitcoin goes to 10,000 USD and you can generate a few thousand adresses a day.. or how many adresses would it be possible to create and check? A few hundred thousands maybe With a strong computer?

What if, in the future, Bitcoin is at 100,000 USD and have 1 billion active users. Is this still not a threat?

Mere peanuts compared to Graham's number, which is so large we don't know many digits it contains.

http://en.wikipedia.org/wiki/Graham's_number

 

That gets you MUCH closer to the estimated number of atoms in the universe.

2²⁵⁶ is approximately 10⁷⁷

It's already been done.


You'd be better of solo-mining.  You'll make far more from the block reward than you'll ever get from trying to brute force addresses with bitcoins in them.

There isn't enough energy output left from the entire remaining life of our sun to power a computer that can generate enough addresses to give you anything resembling a chance.

Maybe that person was assuming 256 bit addresses.

what if someone made a computer script that automatically created addresses and checks the balances? i'm guessing that if it were the case, it still wouldn't be worth it, considering that the electricity costs would likely be more than the potential $$$ you can make by stealing from others.

The number of bitcoin addresses is big.  Very VERY big.  But, to say that there are more bitcoin addresses than atoms in the entire universe is what would be called an exaggeration.

The last I saw, the number of atoms in the entire observable universe is estimated to be within the range of 10⁷⁸ to 10⁸².

The number of possible bitcoin addresses is less than 10⁴⁹.

The last reasonable estimate I saw for atoms in the "Solar System" was on the order of 10⁵⁷.

If we exclude the Sun, and add up all the rest of the atoms in the solar system, I think the number is somewhere around 10⁵⁴

Aren't the addresses generated randomly without regard to checking to see if it already exists anyways? Such that even if you had transfers, if someone happened to be on that address on their generation it would still go through.