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Bitcoin puzzle #66 was solved: 6.6 BTC (~$400k) withdrawn

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Re: Bitcoin puzzle #66 was solved: 6.6 BTC (~$400k) withdrawn

#391

Post by the_clarence »

nullc wrote: post #377
the_clarence wrote: post #373

Earlier quoted context omitted.

But that's not the range in question, this one has 66 bits. You're describing a meet in the middle attack but the runtime would be too high

My example is specifically for a 66-bit range. There are two loops in my post, one removes 2^33 multiples of 2^33, the other builds a table to check for values with a 33-bit range. My example will find a solution in a 66-bit range using only 2^34 point operations and 2^33 table lookups. Work thought it, I think it'll be more informative than me simply repeating myself further. If you're still confused, ask specific q…

Oh right nevermind. For about 300GB of data. I would assume this is what they did them

Re: Bitcoin puzzle #66 was solved: 6.6 BTC (~$400k) withdrawn

#392

Post by mikhailfranco »

buzzert wrote: post #376
Scramblejams wrote: post #340

Earlier quoted context omitted.

Coin ignorant here: Why would it not be worth anything?

I think the other factor to consider is that once you try to sell $200B worth of Bitcoin, the value of Bitcoin suddenly drops to near zero (due to supply/demand).

Which is also why all those company market caps you see quoted everywhere are totally ridiculous. A company is not worth the latest price of a small share transaction multiplied by all the outstanding shares.

Re: Bitcoin puzzle #66 was solved: 6.6 BTC (~$400k) withdrawn

#394

Post by kragen »

kragen wrote: post #368
BobAliceInATree wrote: post #347

Earlier quoted context omitted.

electricity is basically fungible (minus a distance factor). So if you're using up the cheap, renewable electricity for mining, guess what you're using for everyone else's day-to-day electricity? Yep, fossil fuels. ( https://www.theguardian.com/technology/2022/feb/18/bitcoin-m... ) One major exception to this is geothermal electricity in places like iceland where there's abundant green electricity, but you can't tran…

the distance factor is a primary consideration when it comes to electricity; most electricity is consumed within hundreds of kilometers from where it's produced, because only in china is there uhvdc transmission, and even inside china there isn't nearly enough uhvdc and hvdc transmission capacity to meet demand consequently, there are lots of places where there's abundant green electricity that can't be economically…

correction, since 02017, there's also uhvdc transmission in brazil from the belo monte dam. 66% of electrical generation in brazil is hydroelectric

https://en.wikipedia.org/wiki/Xingu-Estreito_HVDC_transmissi...

https://en.wikipedia.org/wiki/Xingu-Rio_HVDC_transmission_li...

Re: Bitcoin puzzle #66 was solved: 6.6 BTC (~$400k) withdrawn

#395

Post by Dylan16807 »

mikhailfranco wrote: post #392
buzzert wrote: post #376

Earlier quoted context omitted.

I think the other factor to consider is that once you try to sell $200B worth of Bitcoin, the value of Bitcoin suddenly drops to near zero (due to supply/demand).

Which is also why all those company market caps you see quoted everywhere are totally ridiculous. A company is not worth the latest price of a small share transaction multiplied by all the outstanding shares.

There's enough depth in the stock market to make company market caps pretty real. If you had a big chunk of a company, you could sell it for close to the trading price. I'd be shocked if you couldn't get half, as a nice round example number.

I would not be shocked if trying to sell $200B in bitcoin gets you far less than half.

Re: Bitcoin puzzle #66 was solved: 6.6 BTC (~$400k) withdrawn

#396

Post by Dylan16807 »

GTP wrote: post #272
mrb wrote: post #136

Earlier quoted context omitted.

No private key was posted too early. What happened is the person who spent all the computing power to brute force the 66 bits broadcasted, naively, a transaction to send the 6.6 BTC reward to his wallet. However, when doing so, the public key is by design revealed on the blockchain. Someone's bot whose sole purpose is to steal this puzzles rewards was monitoring the blockchain and spotted the transaction before it go…

It shouldn't be so easy to derive a private key from the corresponding public key. Is the attack you're referring to working because most of the bits of the private key are already known or am I missing something else here?

> It shouldn't be so easy to derive a private key from the corresponding public key.

What specifically are you calling "so easy"?

If we're talking about "2^(n/2)", I don't see the problem. Why shouldn't it be that?

Re: Bitcoin puzzle #66 was solved: 6.6 BTC (~$400k) withdrawn

#397

Post by Dylan16807 »

y42 wrote: post #388

What I don't understand, hopefully someone is still reading it here: The hint says this: >> First output: take random number from 2^0 upto 2^1-1, use it as private key >> Second output: take random number from 2^1 upto 2^2-1, use it as private key >> Third output: take random number from 2^2 upto 2^3-1, use it as private key To me it sounds like that wallet #10 has a range from 2^9 to 2^10 - 1 - so you don't actually…

What do you mean by previous bits? Where are you seeing how "everyone is crawling"?

With each puzzle, you know that the top bit is 1, and nothing else. Every bit below that is unknown, and you need to go through the whole range of n-1 bits. Puzzle #10 has 9 bits to guess, because it's between 10_0000_0000 and 11_1111_1111. Puzzle #66 has 65 bits to guess. If someone says 66 unknown bits they've misspoken.

Re: Bitcoin puzzle #66 was solved: 6.6 BTC (~$400k) withdrawn

#398

Post by Dylan16807 »

mrb wrote: post #2

Discussion thread here: https://bitcointalk.org/index.php?topic=1306983.msg64526037#... Bitcoin puzzles are private keys with just a few unknown bits so that anyone can bruteforce them to collect a reward. Puzzle 66 contained 66 unknown bits and had 6.6 BTC deposited into it by the initial puzzle creator. The private key was 0x000000000000000000000000000000000000000000000002832ed74f2b5e35ee or 256 bits with mostly ze…

Note: The size of the puzzle is the number of unknown bits plus one, because the top bit is always set. Puzzle #66 had 65 unknown bits.

Re: Bitcoin puzzle #66 was solved: 6.6 BTC (~$400k) withdrawn

#399

Post by y42 »

Dylan16807 wrote: post #397
y42 wrote: post #388

What I don't understand, hopefully someone is still reading it here: The hint says this: >> First output: take random number from 2^0 upto 2^1-1, use it as private key >> Second output: take random number from 2^1 upto 2^2-1, use it as private key >> Third output: take random number from 2^2 upto 2^3-1, use it as private key To me it sounds like that wallet #10 has a range from 2^9 to 2^10 - 1 - so you don't actually…

What do you mean by previous bits? Where are you seeing how "everyone is crawling"? With each puzzle, you know that the top bit is 1, and nothing else. Every bit below that is unknown, and you need to go through the whole range of n-1 bits. Puzzle #10 has 9 bits to guess, because it's between 10_0000_0000 and 11_1111_1111. Puzzle #66 has 65 bits to guess. If someone says 66 unknown bits they've misspoken.

yeah, thats what i meant, just to make clear "how" I am thinking it: It's just iterating through integers from n to k and calculating secp256k1, sha-256 and ripemd. So:

>> Puzzle #10 has 9 bits to guess, because it's between 10_0000_0000 and 11_1111_1111

means that I don't have to start at 0000 0000 0000 ... everytime, I can actually start at 2^5 and look up to 2^6 - 1, for example for the 6th address.

Re: Bitcoin puzzle #66 was solved: 6.6 BTC (~$400k) withdrawn

#400

Post by Dylan16807 »

orf wrote: post #337
bdamm wrote: post #336

Earlier quoted context omitted.

Presumably there is a generator function that maps key IDs into actual keys that can be re-computed at will.

How could this work with less than 1 bit of data per key? Assuming there are no duplicates, which is a sensible assumption, you’d need a minimum of 100,000,000 bits to store 100,000,000 unique entries larger than 1 bit with even a perfect hash function.

In general, when you're storing a list of numbers, there are many situations where you can go below 1 bit per number.

The easiest one to think about is storing the deltas between each number. Let's say 80% of your deltas are 5. If you use arithmetic encoding, then storing a 5 only takes about 1/3 of a bit. It's not hard to come up with probability distributions where the average amount of bits per entry is less than 1.

Also, back in the realm of perfect hashes, once you're more than half full it becomes more efficient to store the missing numbers. If your perfect hash has 100,003,000 possible outputs, then your worst case is around 50k unique entries. By the time you encounter 100k unique entries you only need to keep track of the 3000 you haven't seen yet.

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