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Other => Beginners & Help => Topic started by: walkerbitco on June 05, 2018, 03:21:29 AM



Title: what if two people generate the same private key ? Is that possible
Post by: walkerbitco on June 05, 2018, 03:21:29 AM
what if two people generate the same private key ? Is that possible


Title: Re: what if two people generate the same private key ? Is that possible
Post by: Cryptocoinbob on June 05, 2018, 03:24:08 AM
Looking at the post, I thought "Can two people have the same DNA? "

So, I looked on google, and found that it is possible but very very very very rare.

https://www.nytimes.com/2008/03/11/health/11real.html




Title: Re: what if two people generate the same private key ? Is that possible
Post by: target on June 05, 2018, 03:25:26 AM
what if two people generate the same private key ? Is that possible

Even  if its possible then what will happen then? Its not like the  can hack each other.
Who would have know we two have same private kay? This is not a problem  wwe woth can have the same password either but I don't think anyone can actually see we have same passsword which is p@ssw0rd. mnemonic phrase might be common.


Title: Re: what if two people generate the same private key ? Is that possible
Post by: Cryptocoinbob on June 05, 2018, 03:29:30 AM
what if two people generate the same private key ? Is that possible

Even  if its possible then what will happen then? Its not like the  can hack each other.
Who would have know we two have same private kay? This is not a problem  wwe woth can have the same password either but I don't think anyone can actually see we have same passsword which is p@ssw0rd.

Is it possible to have the same public and private key pair that got generated by the algorithm ?  How is the algorithm generating public and private keys.. Do you know or can you share a link to study ?


Title: Re: what if two people generate the same private key ? Is that possible
Post by: danielberryfy on June 05, 2018, 03:32:28 AM
what if two people generate the same private key ? Is that possible

theoretically possible, but not in reality ... The probability is very very low


Title: Re: what if two people generate the same private key ? Is that possible
Post by: target on June 05, 2018, 03:35:12 AM
what if two people generate the same private key ? Is that possible

Even  if its possible then what will happen then? Its not like the  can hack each other.
Who would have know we two have same private kay? This is not a problem  wwe woth can have the same password either but I don't think anyone can actually see we have same passsword which is p@ssw0rd.

Is it possible to have the same public and private key pair that got generated by the algorithm ?  How is the algorithm generating public and private keys.. Do you know or can you share a link to study ?

I didn't say its possible and I didn't say that its true two address can have same private key. I just set out an example that its not going to be a problem if  there is the same private key. I just set an example that it wouldn't be a threat to security if there are two address having same private key. Don't ask me a link about a study of this. Its just my logic, you  use yours.


Title: Re: what if two people generate the same private key ? Is that possible
Post by: bob123 on June 05, 2018, 07:52:48 AM
Is it possible to have the same public and private key pair that got generated by the algorithm ?  How is the algorithm generating public and private keys..

Theoreticaly, yes it is possible.
But practically, it is not possible because the chances are almost zero.
You could use the whole energy available on earth and wouldn't generate a private key which already has been generated. In fact you would have created < 1% of all possible private keys.

Private keys are not generated by any algorithm. A private key is just a 256 bit random number.
The public key is then calculated through multiplication on the eliptic curve (in bitcoins case: secp256k1).
The address is then derived by calculating the hash: RIPEMD-160(SHA256(public_key)).


Title: Re: what if two people generate the same private key ? Is that possible
Post by: HCP on June 06, 2018, 02:17:00 AM
What if two people generate the same private key? The simple answer is that they  will both have the ability to spend any UTXOs that are assigned to that private key. (First to spend wins!)

Is it possible? Yes

Is it likely? No. I forget the exact maths or whom it was that calculated it, but I think the odds of that happening were the same as being struck by lightning while taking a crap seventeen years in a row :P

Edit: found it! https://bitcointalk.org/index.php?topic=104461.msg1315279#msg1315279


Title: Re: what if two people generate the same private key ? Is that possible
Post by: LTU_btc on June 06, 2018, 10:24:36 PM
Everything is possible in this world :D. But it's almost impossible to generate same Bitcoin address for two people - chances are close to zero. To generate same private keys chances are many times smaller than to generate same Bitcoin address.
HCP above posted link to exact calculations made by one smart guy.


Title: Re: what if two people generate the same private key ? Is that possible
Post by: chiller on June 06, 2018, 10:46:30 PM
Yes it is possible and it is proven by project called "Large Bitcoin Collider" https://lbc.cryptoguru.org/about. You can read more there. 
What happens then?
Well that part also is covered in the LBC.
In a nutshell
  • Spend it
  • Do nothing


Title: Re: what if two people generate the same private key ? Is that possible
Post by: DrMill on June 07, 2018, 04:08:41 AM
I think it's possible, theoretically. But, due to so so low probability, we just don't need to worry about the risk, at least for several years to come.

It's similar to the situation that there's a person who looks exactly like you on this planet. If it ever happens, you hardly know about the existence of the other, therefore do not have to worry about what if your spouse make mistake: going with your identical person, instead of you.  :D. Just kidding!


Title: Re: what if two people generate the same private key ? Is that possible
Post by: mu_enrico on June 07, 2018, 04:16:32 AM
what if two people generate the same private key ? Is that possible

Since private key is 256-bit random number, there's no way, in reality, two people generate the same private key.
It's like two people flipping a coin 256 times and expect the exact same result.

PS: If these two people flipping a coin 50 times and have the exact same result. I'd call that a miracle.