Hacker News Reader

Comment by tromp | Hacker News Reader

Curiously, after hitting a random page and >> twice, I came upon this page https://playxo.com/bitcoin/904625697166532776746648320380374... that had several keys in use in the past.

I would expect this website, in the rare event of discovering some positive balance, to try spending it right away...

View on HN

The site doesn’t need people’s luck to find any active wallet, cause it could operate without them. The probability is so small that any reasonable time spent on including a spending routine would be pointless.

Unless the author trusts in luck or has too much free time on their hands.

Edit: or waits for someone to check a page containing their own private key.

Someone sent 2.3BTC to the last possible address in 2017, worth ~$5k at the time. It was hoovered up to another address in a few hours.

Hobbies of crypto millionaires?

The first page (<<) has similar patterns. Must be someone testing/debugging with hardcoded numbers.

Nah, it goes in an order. Base58check is used to convert byte arrays into the readable bitcoin addresses. So the the first address (5HpHagT65TZzG1PH3CSu63k8DbpvD8s5ip4nEB3kEsreAnchuDf) has a byte array, in hex, of: 0000000000000000000000000000000000000000000000000000000000000001

Some people used those early addresses on purpose. Maybe for testing or something or I guess maybe due to a bug or something.

Usually you use address 0 to burn your coins, sometimes this is used to interpret a layer2 command.

Hey John - I came here to ask the same question.

How is that possible. Same happened to me.

>> leads to the "end" page, it's not as I though a "big jump" from some random page... thus I suspect it's simply addresses that are low entropy, at the end of the range.

Possible causes are caching or random seeding using integer seconds.

Or someone implementing their own bitcoin client and using a predictable key for fun

They're the trivial wallet addresses (close to the beginning and end of the search space). I would expect them to be used for debugging and testing in the early days.

What makes them trivial, how are they generated?

> A private key is basically just a number between 1 and 2^256

It's like saying "I'm gonna pick a random number between 1 and a trillion", and then picking 999,999,999,995. Probably not a smart idea given that you don't want anyone else to be able to guess your number.

But the values are generally generated pseudo randomly by machine. This seems similar to the birthday problem, where the odds of encountering a value in a given range is higher than you'd expect.

The birthday problem means that the number of values you have to choose to have a 50% chance of a collision scales approximately with the square root of the size of the space. [0]

2^(256/2) is way, way bigger than the number of used bitcoin addresses, which is about 33 million according to this csv [1].

[0] https://en.wikipedia.org/wiki/Birthday_attack#Mathematics

[1] https://bitkeys.work/download.php

1. yes, generally and ideally the private key is generated pseudo randomly. But at the beginning or for testing, people might have manually picked a private key.

2. the birthday problem basically halves the exponent security wise. The rule of thumb: If you have N possible outcomes, then after around sqrt(N) guesses the probability of a collision approaches 0.5. So, for birthdays, it's 365 outcomes, so with 19 or 20 people your risk of collision already approaches a half. For BTC private keys, there are 2^256 possible, so with 2^128 guesses you'd approach a likely collision. Fortunately, that's still 1e38, so if you check 1e10 per second, you'd still need 1e20 years to get there.

ECDSA private keys can be arbitrary strings of random bytes of a certain length (unlike RSA, where we need to find prime factors). The first page is roughly the equivalent of using a low single digit number as your password.

the first page has almost all of them used.

the first one having 7 BTC sent and received with the recent transaction in 2021-11-25 22:56. looks like its the wallet id 1.

also the 0 page haave some as well. looks like someone is monitoring those address.

https://playxo.com/bitcoin/1

https://www.blockchain.com/btc/address/1EHNa6Q4Jz2uvNExL497m...

https://playxo.com/bitcoin/0

The first address that has never been used is 61. Would be fun to keep track of over time.

It's a game like feeding the birds to see which bird will be able to grab the bread first.

Anybody can throw money and watch which robot will catch it.

Sometimes the addresses are reloaded (anybody can reload them by sending money to them). And usually when they are reloaded somebody grab the coins on the next block. The amount of money are not important ~1 USD.

Anybody that has guessed the private key can grab the money if he is aware that it has been reloaded, and then it has to pick the fees higher than the other so that his transaction get preferentially chosen by the miners.

The following address for example seems to be one of those bread crumbing bot : https://www.blockchain.com/btc/address/bc1q0ct0pus328qv2veln... (Note that the public address begins with (bc1q0ct0pus), (so presumably someone has searched for a private key whose public key has a fitting name for a bitcoin grabbing bot) that has managed to grab a few times recently from 1EHNa6... (the address whose private key is the first possible private key).

Presumably it has found other feeding spots as it has so far collected from different sources over the course of 1 year : 0.01274447BTC

>> goes to the last page

Reply on news.ycombinator.com