Can someone have my private key ?

[rasho321]

So, I had this question in my mind for a little time and now I think I really need an answer.
If you create a btc address you get the private key of that address, what if this address is already in use ?
I know there is a really low probability but this can happen, am I right ?

[1713610027]

1713610027

[1713610027]

1713610027

[1713610027]

1713610027

[ranochigo]

Yes. It can happen. There is no mechanism that prevents this from happening in an infinite time space. In fact, more than a private key can correspond to a single address. If that ever happens, then all of them can be used to spend the funds in that address.

The probability is not just low, its incredibly low if your wallet has a functional random number generator.

[Adeyemi]

You don't get access to all the private keys of the Bitcoin addresses on a centralized exchange. These exchanges alone have access to your private keys. The possibility of your address been previously used is there but I don't think it's happening.

If your Bitcoin address is already in use, then you'll have access to its past transactions on the blockchain. Just check to confirm. Don't forget that the blockchain is A PUBLIC LEDGER THAT CONTAINS THE DETAILS OF ALL PAST AND PRESENT TRANSACTIONS.

[Kakmakr]

I think you might see how impossible this is, after you watched this video : https://www.youtube.com/watch?v=ZloHVKk7DHk < The math behind this is mind blowing to say the least >

I am not saying it is impossible, but looking at the math, I can quite confidently say I am 99.9999% sure that it would not happen.

In a scenario like this, both people with the same private key would be able to spend the coins.

[vit05]

 There is a website where you could check all private keys. It will take some time to find, more them your whole life, but your private key is in there.
http://www.allprivatekeys.com/allprivatekeys.php

One thing that few understand, is that any password for anything you do on the internet is available. The password you use in your email, to enter here in the forum etc.

Because all services use a finite combination of characters.

But in order to find one exactly password, you need to try several times. In the case of Bitcoin, the possibility of finding by trial can be considered impossible. And it is still possible to use a multisig or use another layer of security

[bitbunnny]

Centralized exchanges and Bitcoin wallet like blockchain have access to your private key.
From security aspect this is very dangerous because there is no guarantee that someone will not misuse it.
But in practice  I have never heard of case when there is address that was already in use.

[HeRetiK]

So, I had this question in my mind for a little time and now I think I really need an answer.
If you create a btc address you get the private key of that address, what if this address is already in use ?
I know there is a really low probability but this can happen, am I right ?

It can happen if your wallet uses a faulty RNG (= random-number generator). That is, a biased / predictable RNG that results in a greatly reduced keyspace.

This happened back in 2013 and shows the importance of properly implementing security standards:

https://thehackernews.com/2013/08/hacking-bitcoin-android-vulnerability-digital-wallets.html


Short of such software implementation failures the chance of a private key collusion is, as already mentioned by the other posters, infinitesimal.


Regardless of that you might want to check out the Large Bitcoin Collider that tries to put your worries to the test in practice:

https://bitcointalk.org/index.php?topic=1877935.0

[chocolaty]

So, I had this question in my mind for a little time and now I think I really need an answer.
If you create a btc address you get the private key of that address, what if this address is already in use ?
I know there is a really low probability but this can happen, am I right ?

Millions of people have their own private key and it is extremely impossible for a stranger to know that you are that person he shares the same private key with. Similar private keys could happen because combinations of characters are finite. But do not let this bug your mind because this is a one in a million chance to occur.

[LoyceV]

I know there is a really low probability but this can happen, am I right ?

Get your phone, punch in a random number and call me! When I pick up, tell me my creditcard number and my date of birth.
This is still many billion times more likely than you guessing anyone's existing private key. So yes, it's a very low probablility, but no, it can't happen that you get someone else's private key.

[xk85jq]

For me,i dont think it will be happen but it might be happen you can recognizing it because wallet cannot be open unless you put the real private key that can unlock your personal savings wallet

[BTRIC]

So, I had this question in my mind for a little time and now I think I really need an answer.
If you create a btc address you get the private key of that address, what if this address is already in use ?
I know there is a really low probability but this can happen, am I right ?

Yes, it can happen in theory.
However, the chances of it happening are much lower than "really low probability", more like "virtually impossible low probability".

Of course, as others have pointed out on this thread, if you are not using a good source of entropy or an otherwise flawed random number generator, the chances of it occurring rise.  The reason is because the limited entropy and/or RNG flaws effectively lower the number of possibilities that it will ever generate.

To visualize this, for example, if a normal key to a house has 10,000 combinations that the "lock making machine" randomly assigns to doorknobs, you can look at a flawed RNG as if part of the lock making machine is stuck, so in reality it will only ever generate 1,000 different combinations.

Randomness is valuable.  If using virtual machines to store wallets/run nodes/etc., ensure that they have access to a good source of entropy.  VMs often have poor entropy without specific steps being taken to increase the levels (platform specific).

Best regards,
Ben

[Mpamaegbu]

I know there is a really low probability but this can happen, am I right ?

Just like the serial numbers on a call card, it is impossible to get corresponding numbers. Private Keys are safe until revealed to another party.

You don't get access to all the private keys of the Bitcoin addresses on a centralized exchange. These exchanges alone have access to your private keys. The possibility of your address been previously used is there but I don't think it's happening.

What is your point?

[bob123]

I know there is a really low probability but this can happen, am I right ?

Just like the serial numbers on a call card, it is impossible to get corresponding numbers.

With a small difference:

Amount of possible private keys: 2²⁵⁶ -> thats 1,15792089 × 10⁷⁷

Amout of possible numbers (with 20 digits for example): 1 x 10²⁰

So there would be about 10⁵⁷ times more private keys than possible numbers in your example.
Thats way way worse (in terms of relation between those two) than comparing the flip of a coin to winning the lottery.

[Thirdspace]

If you create a btc address you get the private key of that address, what if this address is already in use ?

if it does happen, which very less likely to happen in your lifetime, it is called an address collision
read this https://en.bitcoin.it/wiki/Technical_background_of_version_1_Bitcoin_addresses#Collisions_.28lack_thereof.29

I know there is a really low probability but this can happen, am I right ?

It is more likely that the Earth is destroyed in the next 5 seconds, than that a collision occur in the next millenium.

there's a group of people in the project which attempt to generate address collisions
they are called Large Bitcoin Collider there is also a thread about it https://bitcointalk.org/index.php?topic=1877935.0
you can join them and try it yourself how to do "address collision"

[pathapoddo]

It can be. But this is low probability. But you're tension is correct. But you need to careful with your private key. Anything can happen. So be careful.

[lionelho]

Unless you do not keep it safely, no one is able to have your private key.

[BTRIC]

So, I had this question in my mind for a little time and now I think I really need an answer.
If you create a btc address you get the private key of that address, what if this address is already in use ?
I know there is a really low probability but this can happen, am I right ?

Here's another website that has your private key: https://lbc.cryptoguru.org/dio/1

However, it may take you a little while to find it on there, since it says at the top of the page:

Page 1 out of 904625697166532776746648320380374280100293470930272690489102837043110636675

This website doesn't actually have 904625697166532776746648320380374280100293470930272690489102837043110636675 pages stored to disk, as that would take up quite a bit of space.  Instead, it produces the pages on demand as you flip through them.  You can also change the "/1" in the URL above to "/[any number between 1 and 904625697166532776746648320380374280100293470930272690489102837043110636675]" to go directly to that page.  Though I must admit, I haven't tried them all.

As you can see, the chances are so small that someone else would have your private key.  In fact, it's extremely likely to take billions of years to find it.

But, of course, the first guess could be right!  Just extremely improbable.  So improbable that it's hard to imagine just how unlikely that would be.

A Bitcoin private key is safer than the safest lock in the world.  It is so safe that people have trusted hundreds of billions of dollars in Bitcoin to the security of the public address/private key combination.  Many altcoins use the same method for their addressing, though the namespace may differ, so people storing other coins, such as Litecoin, have also trusted this system for addresses and private keys.

Fun fact I discovered while searching around looking for analogies for this reply.  Did you know that a piece of paper folded 103 times is as thick as the Universe?  I didn't!

Happy hunting!

Best regards,
Ben

[AGD]

...
This website doesn't actually have 904625697166532776746648320380374280100293470930272690489102837043110636675 pages stored to disk, as that would take up quite a bit of space. 
...

Nice posting, but ...
"Quite a bit of space" sounds, like it is possible to store all the data somewhere. Just to imagine:

You'll probably use a fast high end SSD to store all the the addresses, which would mean that
 - there is not enough space on earth for all these SSD's (not counting the computers to run them).
 - there is not enough energy available to run these SSD's.

[btctousd81]

yes, that can happen but chances are pretty low.

i regularly go to https://allbitcoinprivatekeys.com/

enter any random page number

e.g.

54458576546545646546564646544
https://allbitcoinprivatekeys.com/54458576546545646546564646544

454657841321321312302020202020002025644878978978789797897
https://allbitcoinprivatekeys.com/454657841321321312302020202020002025644878978978789797897

and check each address for the balance.,

[CryptoVerseStudent]

It's nearly impossible to happen. Just imagine the 54 number lottery has a total 25,827,165 number combinations. The wallet address that we have are not just combination of numbers but alphanumeric combinations. How many combinations are there? A looooooot!