About Collision

[Amph]

first of all this is not about the probability of a collision, we all know about that

let's assume that one happened already, there is a way to know if this is true? how can someone be sure that one address was not replicated already aside from the improbability?

[Herbert2020]

if you generate a duplicate address (which is not going to happen) all the wallets whether Full wallet or SPV will show you the transactions that said address had before, and you can see that even if there is no UTXO left in it!

and this is apart from the extremely small chance of that happening. i am sure someone is going to come along and break down the math here soon.

[Amph]

if you generate a duplicate address (which is not going to happen) all the wallets whether Full wallet or SPV will show you the transactions that said address had before, and you can see that even if there is no UTXO left in it!

and this is apart from the extremely small chance of that happening. i am sure someone is going to come along and break down the math here soon.

if it is a new brand address it has no transaction

[shorena]

first of all this is not about the probability of a collision, we all know about that

let's assume that one happened already, there is a way to know if this is true? how can someone be sure that one address was not replicated already aside from the improbability?

If the address wasnt used but someone else also has the private key, you cant know.

[franky1]

schrodinger's cat

if you cant see it, did it really happen?

[shorena]

schrodinger's cat

Not really, the address is either used (for payments) or not. It wouldnt be in a state where both is equally likely.

if you cant see it, did it really happen?

Thats rather philosophical, but idea that the world only is in motion when humans perceive it is rather strange to me, so yes.

[franky1]

Not really, the address is either used (for payments) or not. It wouldnt be in a state where both is equally likely.

if 2 people have an cat (same address) in a box (wallet address pool of 20-100 addresses yet to be used) but cannot yet see if its an active address ready to jump out and walk around (collide and be spent by other person) or not.. ...  have they yet collided..

my point is that you can never know until you do something.
general point to everyone

but to avoid the risks, things like random numbers/wallet seed/private key entropy should be high to avoid the chance.

assume you have the best random entropy that exists today
the chances of you choosing a specific address someone you know already has, colliding with you and/or you finding that same specific address is
2 out of 904625697166532776746648320380374280100293470930272690489102837043110636675

however the chances of a random collision with a random address is
a few million out of 904625697166532776746648320380374280100293470930272690489102837043110636675

if randomness does not produce a random factor of 75digits.. then your not grabbing a private key from the fall allotment of possible keys

EG if randomness was only between 0-200
then it will only produce 200 keys before repeating (colliding) with keys its already produced

EG if randomness was just an 8 character (alphabet only) brainwallet password
then there will only produce 208827064576 keys before repeating (colliding) with keys its already produced
there has already been many brain wallet collissions. so yes collissions have happened and will happen
there has already been a few bad RND collissions. so yes collissions have happened and will happen

but to ensure the chances of you colliding. can be mitigated by having a 75 digit random factor to maximise the pool of addresses you can randomly land on

[manselr]

Gmaxwell and others have been advising against brainwallets for a reason... they are not and will never be safe. Just get bitcoin core and backup your wallet.dat, it's the best way to go to avoid weird shit from happening.

I guess electrum is safe if you like that route, but i feel safer with core. Also worrying about this thing is like worrying about the chances of a big asteroid hitting earth and destroying it... it can happen, but the chances are so slow that it's better to not think about it to avoid unnecessary stress.

[shorena]

Not really, the address is either used (for payments) or not. It wouldnt be in a state where both is equally likely.

if 2 people have an cat (same address) in a box (wallet address pool of 20-100 addresses yet to be used) but cannot yet see if its an active address ready to jump out and walk around (collide and be spent by other person) or not.. ...  have they yet collided..

my point is that you can never know until you do something.
-snip-

Hmm, makes sense seen like that.

Gmaxwell and others have been advising against brainwallets for a reason... they are not and will never be safe.
-snip-

That was not the reason, the reason was and is that humans are bad at producing sufficient entropy for the brainwallet to be random (see the post by franky). This is true for the security of all wallets, if the entropy source sucks a collision is (significantly) more likely.

[YuginKadoya]

I think that bitcoin wallet would not allow anybody to have a collision with an existing address that would be not a problem of every users of bitcoin,

well if these kind of problem would occur in bitcoin, people would just make their new account and hope they can get that has a bitcoin on it, There would be an uproar in the bitcoin community that certain bitcoin would just ended up to another person

[Lauda]

-snip-

Your post is a classic example of a useless shitpost. Please stop responding in threads where the subject is out of your league.

Gmaxwell and others have been advising against brainwallets for a reason... they are not and will never be safe.
-snip-

That was not the reason, the reason was and is that humans are bad at producing sufficient entropy for the brainwallet to be random (see the post by franky). This is true for the security of all wallets, if the entropy source sucks a collision is (significantly) more likely.

This should probably be watched by anyone who wants to use a brainwallet: DEF CON 23 - Ryan Castellucci - Cracking CryptoCurrency Brainwallets. He even posted an update (not entirely sure if the account is genuine):

Ryan Castellucci 6 days ago
The current release of brainflayer is much faster than what I released at DEFCON. Currently, it's only $40 to check 1 trillion passphrases on AWS, which works out to 25 billion per dollar.

[franky1]

-snip-

Your post is a classic example of a useless shitpost. Please stop responding in threads where the subject is out of your league.

lauda as not only a moderator, but as a sig campaign organiser yourself. you could and should just report him to his sign campaign manager and lose him his earning status. that would shut him up
...

The current release of brainflayer is 1 trillion passphrases on AWS,

a trillion pass phrases. thats only:
9 alphabet characters deep
8 alphanumeric characters deep
7 alphanumericsymbol characters deep

[Lauda]

lauda as not only a moderator, but as a sig campaign organiser yourself. you could and should just report him to his sign campaign manager and lose him his earning status. that would shut him up

I've already done that, thank you for the heads up though.
Let's get back to the interesting stuff, shall we?

if 2 people have an cat (same address) in a box (wallet address pool of 20-100 addresses yet to be used) but cannot yet see if its an active address ready to jump out and walk around (collide and be spent by other person) or not.. ...  have they yet collided..

This is actually a very good thought experiment, with the analogy to Schrodinger's cat and quantum uncertainty. I would still be inclined to say that the collision occurred even though it was not observed by anyone. Do collisions that have no impact or have not been noticed by someone matter? I would say no. Even though the chances of one are extremely improbable, it may happen without someone noticing one.

there has already been a few bad RND collissions. so yes collissions have happened and will happen

Standard random generators are quite useless for cryptography indeed. For better randomness, one could attempt to map data from some naturally occuring events (aside from the traditional method of using cryptographically safe PRNG e.g. ChaCha20)

[iamTom123]

I think that bitcoin wallet would not allow anybody to have a collision with an existing address that would be not a problem of every users of bitcoin,

well if these kind of problem would occur in bitcoin, people would just make their new account and hope they can get that has a bitcoin on it, There would be an uproar in the bitcoin community that certain bitcoin would just ended up to another person

The probability of that happening can be close to nothing. I am sure there is a way to check and monitor so that in case it can happen then it can be remedied fast.

[Amph]

first of all this is not about the probability of a collision, we all know about that

let's assume that one happened already, there is a way to know if this is true? how can someone be sure that one address was not replicated already aside from the improbability?

If the address wasnt used but someone else also has the private key, you cant know.

i guess if there was a way, there was also a way for a quantum computer in the future to get the private from the unrevealed public key, so it make sense

but it also true that if someone would see his coin vanished for no reason, suddenly, he can see the address at which they are sent and maybe thinking about a collision...

[DGulari]

-snip-

Your post is a classic example of a useless shitpost. Please stop responding in threads where the subject is out of your league.

Lauda should be banned.  What a fucktard to talk down to people like that.  This forum is full of shitheads and Lauda is their leader.

[mrkevio]

if you generate a duplicate address (which is not going to happen) all the wallets whether Full wallet or SPV will show you the transactions that said address had before, and you can see that even if there is no UTXO left in it!

and this is apart from the extremely small chance of that happening. i am sure someone is going to come along and break down the math here soon.

I don't think there's going to be anybody "breaking down the math" soon. If that will ever happen, it's going to happen because a user has been lucky or so. Otherwise, if anybody finds a formula that works, I guess they'd go for the wallets rich list which would mean total disaster for Bitcoin, probably a price level of 2011-2012.. going back to that year's level isn't fun for anybody. Although the possibility is very small.. I don't think it never happened. Who knows how many addresses have already been duplicated by mistake when generating them offline and nobody found that out? I have printed over 50 I think, I bet the BTC millionaires have to print thousands to hide their original address.

[Kprawn]

Does the problem with the random generator problem at Blockchain.info count as a probability killer?  .... I think as soon as something like

this happens, someone would have made a noise about it somewhere. The thing is, IF it happened to you, would you report it? Let's say the

address has 100 bitcoins for example. I doubt that MANY people would say anything, if that happens to them. 

[DannyHamilton]

schrodinger's cat

if you cant see it, did it really happen?

Actually, from my understanding of the schrodinger's cat Gedankenexperiment, if you can't see whether it has happened or not then it simultaneously BOTH did and didn't happen until it has been observed by someone.

If the state of possible collision is never observed by anyone then it will remain indefinitely in this state of superposition.

If it the state of possibile collision eventually is observed then the wave function will collapse and it will either have happened or not have happened.

During the state of superposition, it will have some percentage of having happened and some other percentage of having not happened.  Those percentages will be determined by the likelihood of it having happened.

[AgentofCoin]

schrodinger's cat

if you cant see it, did it really happen?

Actually, from my understanding of the schrodinger's cat Gedankenexperiment, if you can't see whether it has happened or not then it simultaneously BOTH did and didn't happen until it has been observed by someone.

If the state of possible collision is never observed by anyone then it will remain indefinitely in this state of superposition.

If it the state of possibile collision eventually is observed then the wave function will collapse and it will either have happened or not have happened.

During the state of superposition, it will have some percentage of having happened and some other percentage of having not happened.  Those percentages will be determined by the likelihood of it having happened.

Also, if i recall correctly, there is highly radioactive material in the box, so the cat will die at some point and that
is what is being determined. So the percentage of having happened versus having not happened, is of the death
of the cat, which is a sure eventuality in this experiment.

With the address collision issue, there is an eventuality as well, but for the examples to be comparable, the
address collision can not be a natural occurrence, but with an advanced bruteforcing system designed to cause
and find collisions, which would represent the radioactive material in the box.

But yes, address collision only exists when it is observed in the wild, like when a superposition ends and the
observed result is determined. Problem is that under normal circumstances, whether it is ever observed and
how to prove it is true collision (outside of random number generator errors and etc) is another issue.