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What is the probability of hitting an existing bitcoin private key?
1023 sats \ 15 comments \ @0xbitcoiner 3 Dec 2024 bitcoin_beginners

I know it's extremely difficult for someone to brute force my private key, but if instead of trying to hit a specific private key, we try to hit a valid private key, how likely is it that we'll hit it? How do you calculate this?

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111 sats \ 3 replies \ @DarthCoin 3 Dec 2024

Usually the "bad guys" are going for individual priv keys, not for HD keys. It's easier and could have more probability for a hit and a prize.

That's why is better not to use the same address multiple times, you limit this probability. And also not making it public, on websites, forum signatures etc.

I saw a chart of these calculations somewhere but can't find the link right now. If I will find it, will come back posting it.

Here it's an answer: https://bitcoin.stackexchange.com/a/24070

Good question !

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21 sats \ 2 replies \ @0xbitcoiner OP 3 Dec 2024

That's exactly what I wanted to know. Thank you!

https://bitcoin.stackexchange.com/a/24070

If you prefer diagrams: https://i.sstatic.net/VWwJq.png (there are more addresses in the address space than there are zeptometres, 1/1 000 000 000 000 000 000 of a metre, in the universe's width).

If you prefer maths: http://download.wpsoftware.net/bitcoin-birthday.pdf (by Andrew Poelstra) says (slightly edited):
Using [birthday attack maths], we calculated [above] that for a 0.1% probability of collision, we would need 5.4 × 10^22 addresses in existence. For a 99.9999% chance, we would need 6.35 × 10^24 addresses.

So, even if there were 10^22 bitcoin addresses generated, a collision simply will not happen. But if there were 10^25 addresses generated, a collision absolutely would happen.

Should we worry about this? No, for these independent reasons:

The chance of getting a specific collision, say, a collision with one of your addresses, is still 1 in 2^160 or 1 in 10^48 . So even if you've got a million million million addresses, nobody has a chance of colliding with you.

At the time of this writing, there are less than 10^7 addresses in use in the network. So anyone with 10^25 addresses would only be colliding their own addresses.

Each address takes around 100 bytes to store. (Actually about half that, but we only care about orders of magnitude.) So for the network to support 10^25 addresses, it would take 10 million million terabytes of storage just to record them. (And this is not even touching the problem of searching such a huge data store.

According to sipa, if the current mining network (which is at 25 THash, and the most powerful computing network in the history of the world) were switched over to address generation, the network could generate 2.5 × 10^12 addresses per second (one address generation corresponding to roughly 10 hashes). At that rate, it would take 127,000 years to get so many addresses. It is debatable whether homo sapiens has walked the earth for that long.

With 21 million bitcoins ever existing, and 8 decimal places of divisibility, at most 2.1 × 10^14 can possibly have money on them at once. But in a space of 10^24 addresses, this means that only one in 10^12 addresses could possibly have money on them. So an attacker, after doing the physically impossible 3 trillion times over, has only a one in a trillion chance of getting even one satoshi out of it.
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84 sats \ 1 reply \ @DarthCoin 3 Dec 2024

I like also this image depicting it :)

good luck finding some good fat addresses 😂😂😂. I know you ask for curiosity and learning, not for trying.

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21 sats \ 0 replies \ @Jon_Hodl 3 Dec 2024

This image was the first time that I truly understood the power of bitcoin and came to the conclusion that bitcoin is inevitable.

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20 sats \ 4 replies \ @Satosora 3 Dec 2024

I have heard of people creating millions of addresses to try to do this.
I dont think they have been successful yet.

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10 sats \ 3 replies \ @DarthCoin 3 Dec 2024

WARNING !WARNING !

Open these pages only for fun !
DO NOT PUT ANY OF YOUR BTC ADDRESS IN THERE TO SEARCH! You can be tracked

There are some scamming pages, so be aware!

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0 sats \ 2 replies \ @Satosora 3 Dec 2024

Does the blockchain track your searches?
I have read that many sites are recording searches.

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10 sats \ 1 reply \ @DarthCoin 3 Dec 2024
Does the blockchain track your searches?

You mean a public block explorer website, right?
Because the Bitcoin blockchain in itself do not track your searches.
If you run your own BTC node, you can browse locally all addresses you like (using a RPC block explorer app or running your own mempool space app)

Now, a public block explorer page like blockchain.info, blockstream.info, mempool.space, oxt.me and many others could track your IP and the address you've searched.

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0 sats \ 0 replies \ @Satosora 3 Dec 2024

I see.
Maybe l shouldnt keep bookmarks of my different addresses lol

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11 sats \ 0 replies \ @OT 3 Dec 2024

Unimaginably extremely difficult. Like picking a grain of sand from all the worlds beaches (but much much more difficult than that).

Don't bother trying.

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0 sats \ 0 replies \ @Jon_Hodl 3 Dec 2024

The odds of brute forcing a private keys for an address are 2^128 but I think there's some nuance to this.

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0 sats \ 0 replies \ @Akg10s3 3 Dec 2024

Great, I hadn't thought about that.. I read the article and all the comments and in both I could find excellent information 🙂

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11 sats \ 2 replies \ @LowK3y19 3 Dec 2024

Probably the same probability as winning the lottery lol

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0 sats \ 0 replies \ @senf 7 Dec 2024

People win the lottery all the time. Nobody is hitting an existing Bitcoin private key.

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0 sats \ 0 replies \ @Aardvark 3 Dec 2024

I think winning the lottery is actually more likely.

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