Hacker News new | past | comments | ask | show | jobs | submit login
310 Bitcoin challenge has been solved (bitcoinchallenge.codes)
272 points by kwikiel 5 months ago | hide | past | web | favorite | 119 comments

I like how bitcoin enables people to set up puzzle bounties like this. Looks like there's a subreddit for it: https://www.reddit.com/r/bitcoinpuzzles/

I might monitor that sub for more bounties, I had no idea there was one this large floating around.

The problem with these puzzles is that you never know if it's actually solvable until it's solved. The author of the puzzle could store any number of bitcoins in some wallet, publish a difficult but unrelated puzzle with the claim that the solution reveals the private keys to the wallet, then laugh while the internet goes on a wild goose chase. It's even more likely since the author is usually anonymous (obviously for good reason). They're fun to ponder over a little, but I'd never invest more time (or money) than I could afford to lose into any of these, no matter the prize.

True. But you can at least verify before starting that the nearly $2 million prize does exist, and is controlled by the creator of the puzzle.

Another problem is that even if the puzzle is legit, you can't claim your prize without wrecking havoc on the environment in the process. At an estimated 850 kWh [0] per transaction, you would need to have a pretty good excuse for performing transactions at all.

[0]: https://digiconomist.net/bitcoin-energy-consumption

Important to mention, is that power consumption is not related to amount of transactions. If bitcoin would allow ten times the amount of transactions tomorrow, the power consumption would not increase.

Power consumption is related to difficulty and the rewards, which is linked to the price of a Bitcoin.

> Power consumption is related to difficulty and the rewards, which is linked to the price of a Bitcoin.

Difficulty is determined by the hash rate of the network. One would expect there to be a link between hash rate and price but that's correlation not causation.

Nonsense, if it costs you $5000 to mine a bitcoin and the price is $1000 then you have no reason to mine it and the hashpower would lower.

From a naïve perspective of only mining for profit that's sort of true.

Lots of people mine for other reasons.

Still probably not related to amount of transactions.

True, since the number of transactions is unrelated to the hashrate of the network.

The actual amount of energy consumed by one bitcoin transaction is actually pretty exactly the amount of money you pay as a fee times the cheapest you can get electricity in the world.

So if you pay $0.2 in fees, you will burn around $0.2 / ($0.1/kWh) = 2kWh of electricity. Note that this is an upper limit since it ignores miner profit (but that will tend towards zero over time).

This is ignoring the block subsidy, but that is independent of the number of transactions will forcibly solve itself over time.

Whether you (or anyone else) perform(s) the transaction or not, the same amount of energy is consumed, so I'm not sure how you got to that kind of reasoning.

Crying about the environment when talking about anything is ludicrous. Do you not poop? Do you not eat? Do you not consume in a modern society? Should we not play games anymore? Should we not watch movies? Find something else to cry about.

Except that the overwhelming majority of mining is done in China and the power is supplied by hydro.

Over half the electricity in China is generated with coal (https://en.wikipedia.org/wiki/Electricity_sector_in_China).

China's building new coal plants to met increased demand.

I would have given it my full time attention if I knew there was a $2M game like this around. That prize is crazy.

The chances of any one person winning that prize are quite slim.

There were only 180 or so registrations so the chances were quite good assuming people were of roughly equal skill and inclination.

The problem was deciding whether there really was the correct private key encoded in the picture.

I mean how do you ensure that this is not a wild goose chase?

It would be roughly analogous to an anonymous millionaire showing a pot of gold on TV (with respectable jewelers certifying that it really is gold) and then saying it will be buried somewhere in Arizona desert, here's the puzzle with the location.

(I believe there are some real life treasure hunts still ongoing based on the above premise)

In this case what stopped me from even trying were the discrepancy in the amounts. 0.1BTC and 0.2 BTC and 0.31BTC seemed like reasonable amounts and then the sudden jump to 310 BTC seemed unreal.

Yes the guy had the private key to 310BTC but was it in the picture? In fact, how do we know that 'Marc' is not someone affiliated with him/her?

> will be buried somewhere in Arizona desert, here's the puzzle with the location.

That's real - it's still out there.


> it will be buried somewhere in Arizona desert

https://en.wikipedia.org/wiki/Masquerade_(book) which then lead into the Hareraiser game which is unofficially the officially worse computer “game” to ever be created.

For more info about the affair in video form there is this talk from the Norwich Game Festival a few years back https://youtu.be/ouvi-fwrfIY

> It would be roughly analogous to an anonymous millionaire showing a pot of gold on TV (with respectable jewelers certifying that it really is gold) and then saying it will be buried somewhere in Arizona desert, here's the puzzle with the location.

Reminds me of the movie "Kumiko the Treasure Hunter" https://www.imdb.com/title/tt3263614/

I suspect they're less slim than you're suggesting if you're a mathematically inclined person.

how do the odds of winning this compare to something like the lottery?

Is there a discussion thread somewhere?

There are 18 three digit hexadecimals in the puzzle. If the answer is a permutation of these, then that's just 18 factorial which is 6.4 * 10^15. That is totally bruteforcable without even thinking about the puzzle (and totally worth spinning up a cluster for).

I don't know anything about bitcoin though and 54 characters seems too short to be a private key? You can also brute force 10 more interspersed characters for a slowdown factor of 16^10 * (64 choose 10) = 9.9 * 10^15. So then it's a total cost of 6.3*10^31. Still bruteforceable but more expensive if you're wrong about it.

From the reddit thread, there's some information on how the basic wallet was solved.: https://docs.google.com/document/d/1nUAhlC_n21ZLZcRAHpLw9G--...

Man I was totally off on how those hexes are used. Thanks for the link!

Also, that's just for the basic wallet with 0.1 BTC in it.

How out of possibly hundreds of different operations that could take the hex table and and that date in possibly 5 different date formats as arguments, would you find out that it's shift key and YYYYMMDD?

Wild guess: start with shift key "301", see "201" come out. Use an 8 for the next, and it's a 3. Bingo.

(I would never in a million lifetimes have guessed that bip thing. How do people even know this?)

BIP39 and 12 word phrases to backup/restore your wallet is common knowledge in the cryptocurrency community.

I think the question is going from decimals to bip39 seed words.

Looking at 426 252 813 1535 1935 1603 1068 1479 1168 756 878 1083 I sure as heck would not think, oh that's bip39 indexes.

I noticed it on the reddit.com /codes subreddit a couple of days ago. It was already solved for the big prize (310).

No, you're like 0.01% done.

At today's rate that is about $1.89 million of btc. Why would someone give away nearly $2m of btc as a publicity stunt?

Because they have 50,000 more. It was very easy to accumulate BTC in the early days. As usual, hindsight 20/20.

Maybe I'm cynical but if I had 50,000 BTC and wasn't ultra bullish on cryptocurrency in general, I would slowly sell it off at a moderate rate sufficient to turn it into real USD denominated securities, while not flooding the market (basically pick some top-20 performing ETFs and mutual funds).

True believers and zealots will of course "HODL".

Lots of people took that exact same strategy at what in hindsight now looks like ridiculously low prices like $1 or $10 or $100. Those people don’t have 50,000 or often any bitcoin left.

Sell 1/4 of your holding every time the price doubles. You won’t make as much money as you could ideally, but you will make a sizable fraction of the maximum, no matter how far or near it will go.

> you will make a sizable fraction of the maximum, no matter how far or near it will go

That won't be true if the price goes high enough. By realistic counter example:

So you start when BTC is at about 10c. You mine around 2000 bitcoins (not bad, $200 for using your old 5870 that was collecting dust). Your card burns out so you quit mining, but implement the above strategy.

You sell 500 at 20c, 375 at 40c, 280 at 80c, etc.

Once bitcoin hits $13k, you have about 10btc left and have made $32k out of your possible gains of $20M.

I would say that less than 1 percent is not a sizeable fraction.

Of course, you would make a sizeable fraction if the price weren't able to double so many times, but the above example is actually quite realistic for some.


Proposed amendment: once you start fearing that bitcoin will crash and wipe out your crypto wealth, begin to implement the "2x 1/4" algorithm. This rule will prevent excessive bleeding at the tail.

I posit in your scenario I would start worrying at $50/btc ($100k), so that's 8 doublings till 13k and by that time I am still holding 10% [(3/4)^8] of my coins (worth $2.6m) plus I have 1.9M in cash [1] I took off the table for a total of $4.5m. Worst case (btc drops instead of going up) I still made $25k.

  [1] https://www.wolframalpha.com/input/?i=sum+(2000%2A(3%2F4)%5Ej%2F4%2A50%2A2%5Ej),+j+%3D+0..8

The problem is picking those points.

At about 30c, I was pretty sure bitcoin would crash, wiping out several hundred dollars which would recover the sunk cost of the GPU.

At $7 was another point I was pretty sure it would crash (and hey, getting $10k out to pay down a car seems like a heck of a lot of money for an internet peculiarity I did no work for).

After $30 when it dropped and Mt. Gox was dying, I was pretty sure it would be dead for good, as were many others.

I don't think your amendment really helps because of two facts:

1. "Fearing it will crash" is something that is difficult to gauge, and I felt since day 1 of bitcoin it was likely to crash and wipe out enough money to pay for a few months of rent or more.

2. Your assumption about that working still fails if it simply doubles more, e.g. if bitcoin goes to $1M/btc, we now have a similar "less than a percent" of possible profit, so you still don't get a significant fraction... And in fact if BTC takes off like that, it likely means the USD will have crashed and thus your previous gains are even less useful.

It's easy to look in hindsight and say "selling fractions from the 10s or 100s would have been a good strategy if we knew bitcoin would stabilize in the 1000s", but such hindsight didn't exist back then, and we still can't be sure it's fully stabilized.

I'm not saying it's a bad strategy; it does seem pretty reasonable. I'm just claiming that it won't guarantee that you end up with a significant fraction of the maximum possible gains, and in fact I don't think any such strategy exists.

When I say "upset" and "fear" I mean something significant - you ought to be upset about it enough to be still upset a year later. "Could have paid for the video card" is not sufficiently upset. "Could have bought a car" would be if you couldn't afford a car to start with. Whatever it is that makes a difference in your life is where you start.

And on the upper end I am restricting myself with "diminishing marginal utility of money" (aka FU money). The range between "too little" and "FU money" is quite narrow, logarithmically speaking.

Let's say that the lower boundary is $100k and FU money is $20m, and same starting conditions as before. 12 iterations would give me $9.7m in cash plus $13m in BTC [2000(3/4)^1250*2^12].

I admit I have deviated from my original "sizable fraction" statement, and I no longer believe in it. But having shifted the goal posts I proclaim these new ones are better - just as satisfying, but a lot more achievable.

That's basically what I did and I ended up with tens of thousands instead of millions (if I had HODLed).

Then again, I've been beset with illness and medical bills, needing to pay for multiple surgeries, so I had little choice.

I presume that the first step of your strategy would be to sell 1/4 of your holding now, since it's already doubled (more than once).

I also presume that you mean, the second time, that you sell 1/4 of the 3/4 you have left.

That strategy works for something like Bitcoin, if you got in near the beginning. It's a really nice strategy for that situation.

But let's say your employer gave you got stock options at $1/share which, at the time they were granted, was exactly the stock price. The stock slowly goes up to $2.50, then slowly falls to below $1.

There are two problems with your strategy in this scenario: First, when has it "doubled"? You were given these options for free, and (on the day they were granted), they are worth zero. As soon as the stock goes to $1.01, they've more than doubled... but you don't want to sell then. (This is also true of Bitcoins that you mined back when that was easy. They were essentially free, so when was the first doubling?)

But if you wait until the stock is worth $2 ("doubling" in another sense), then you only sell once, and only a quarter of your holdings. That's much less gain than you could have made.

Your strategy is a good one for a rocketship like Bitcoin. But you often don't know that you're on that kind of a rocketship until it's doubled several times. If you wait for confirmation that you're on a rocketship, you could miss some much smaller, but still really sweet gains.

What I did when I had the options scenario is essentially your strategy, but with much lower numbers. When the stock went up maybe 25% or 50%, I sold off some of the options. And some more when it went up another 25%. That worked very well for me. But if the stock had been a rocketship, I would have missed out on a lot.

Some of this is bound by the size of the investment. Sub 10,000$ returns are not going to change your life, but when you can start cashing in the equivalent of your annual salary not taking money off the table gets risky.

At that point think of it as a math problem.

Suppose you own a stock that’s never going to issue a dividend, but will do buybacks until eventually the company fails. In such situations you can expect 0-X doublings and a final price of zero.

Now, what strategy works best depends on X, buy and hold is clearly a losing strategy in all situations. Further you don’t know X but you can come up with a reasonable bounds as nothing is going to be worth say 10^30$.

Another approach is to simply constantly sell a fixed percentage each month. That’s very useful if you only have one large investment that does not nessisarily fail, just stop growing exponentially.

If you’re going to rebalance your BTC-cash portfolio every time the price doubles you should probably use Kelly bets, right?

Figures someone already gave it more thought than I did. Good to know!

my general thinking about such meteoric rise of, really, any security like btc/amzn/etc is that this is a cognitive mistake our mind does because of labels. the label amazon wasn't 'Amazon' until it showed consistent growth & shrewd judgement over time. the mistake we make is take that mental object we see now and back project on the past while remorse turns off our analytical ability to see all the possible risks associated with it then.

I always remind myself that most public information is already priced into a stock & for every buyer of a stock there is a seller too.

Yep, it's gambling.

I sold at $15 and was happy that I'd paid for some real fancy graphics cards with the proceeds. Valuation at one point was well over $500k, oh well. Oh and half went poof in MtGox.

I paid for a month's rent with a wallet I'd found with only a transaction fee inside which somehow didn't get deducted from a few years back.

Well lucky you mtgox is getting a civil rehabilitation

True. Had I been involved with Bitcoin, I probably would've done that, myself, and regretted it.

But then again, if we're talking about cashing out for an amount of money on which you can pursue hobbies, live comfortably, and never have to work for another person again... I can't imagine I would regret it that much.

I had bitcoin worth about $50 in 2009/10 go poof when I reimaged a laptop and forgot to backup.

And you habe not been killed by frozen poop falling from an airplane in the sky. Which would have been as likely as Bitcoin becoming a speculative hype. Celebrate that!

Absolutely. A few months earlier I lucked out by selling a ton of stock/funds when I consolidated retirement accounts (I didn’t like the trade restriction during the transfer period). I missed the crash as a result.

Back of the napkin level calculation says that if you had about 675 bitcoin in 2010, it would've been worth $10,625,000 if you'd sold it at the $17,000 peak.

Bitcoin traded between $0.003 and $0.39 in 2009-2010. Source: http://bitcoin.zorinaq.com/price/ Therefore "$50" worth back then could be any amount between 128 and 16667 BTC, worth between $800k and $103M today.

You weren’t kidding about back of the napkin because that’s not 675 * 17k.

He clearly calculated for 625 BTC (it divides evenly to the precise multi-million dollar amount) but had either a typo in his post or in the calculating.

Yes, I typoed 625.

I’m very glad you were wrong. :)

I never calculated the actual potential amount, because I figured it would be depressing, but 9-figures would be beyond depressing.

I’m not sure what I actually paid because I bought it from a friend directly. It was somewhere around 100 BTC. Definitely a cautionary tale about backups and bad luck. But on the other hand, I’ve in whole been the recipient to more than my share of good fortune.

I put the down payment of about eight grand on my last car with Bitcoin I sold in January of 2012. So you can do the math. :)

Now seems like a reasonable time... I mean they have to sell eventually, right? What are they waiting for? Trillions?

Your assets are only really worth something when you sell them. Many more should have sold at the height of the boom last year.

While true, that's hardly actionable. It's impossible to repeatedly pick peaks.

Yeah, it's like saying everyone should have shorted housing in 2006.

If everyone had perfect information... markets wouldn't even function in a recognizable way. If everyone sold before the peak there wouldn't be any peaks.

I guess it all depends on whether you think BTC is more or less "real" than dollars or these supposed "securities" of which you speak.

Maybe they already sold enough to be comfortable for decades and are just trying to make the space welcoming and fun, because if they were into Bitcoin early on they probably love the idea of it and don't just want to make money, they want people to use it.

Maybe they didn't. They could have just drained it from their own wallet to another wallet they own to troll people into working on their puzzle even though they don't plan on giving it up.

If that's what they did, seems like a very cheap way to collect the names/social media profiles/email addresses of all the people discussing the puzzle. Now somebody has a list of at least several thousand profiles who've shared tweets regarding it, sent emails to the info@ address, and can collate it against other lists of persons or pseudonyms interested in both cryptocurrency and this sort of online puzzle.

You are devious. Then execute a massive spearfishing attack.

Or use it as a hiring pool if you're an organization that is recruiting excellent code breakers.

Or just a really easy money laundering scheme.

If the giver was in the US, wouldn't there be some gift tax or other legal problems with doing this?

The prize had to be earned, therefore it is income to the recipient, not a gift. This means it is taxable to the recipient.

US gift tax is the recipients burden (above 14k)

That is almost never true (see https://turbotax.intuit.com/tax-tips/estates/the-gift-tax/L1...). Gift taxes are nearly always the givers burden.

"Let me tell you about the very rich. They are different from you and me." --F. Scott Fitzgerald

I don't see Zuckerberg etc. putting up online puzzles so that some high IQ person can cash in a small fortune. There is something about the cryptorich that is very different from you, me and the regular rich.

Maybe, they are from one of the numerous hacks, and it's anyways hard to sell it all.

Well, Shkreli bought Wu Tang Clan album for 2 million. These things happen.

Worth more than a pre-shredded Banksy, and looks better too!

Well that didn't last long. I see the btc has been drained but who solved it, and where is the solution, will there be one?

According to the author, there will be one after someone solves the 0.31 BTC puzzle.

"I will most certainly do so <provide a solution> but at this moment the 0.31 BTC wallet is still unsolved. I'm surprised because I thought the solution to the 310 BTC wallet was the most complex one." - author

It is possible that the 310 BTC challenge is harder but has higher ROI. If the challenge is very complex, the guy might have just skipped the 0.3 BTC and focused on the big price.

Fits with the conspiracy theory that the 310BTC key wasn't actually in the picture, and the puzzle author just withdrew the money himself. This gives an excuse for not telling a solution, which would hide the fact that there is no solution.

Or fits the obvious assumption that 99% of people and effort were focused on the 310BTC challenge over the .3 one

If I'd focus on the 310, I'd probably do the .3 one first as 'training'. Then again, I hate puzzles so I am probably not representative.

One reward is a thousand times the size of the other - I bet that's the one people focused on.

They should do this when a new Project Euler problems comes out :)


Wow, that's a huge prize. And that puzzle was insanely difficult, I'm very impressed that someone was able to solve it.

I had a lot of fun making a Bitcoin "treasure hunt" last year [1], and I'm going to do another one in the next few months. I think this time it will be more of a coding challenge than a puzzle. And I'm only giving away $500, not $2M! But if that sounds fun, you can sign up for the mailing list at the bottom. I'll also be posting it on https://www.reddit.com/r/bitcoinpuzzles/

[1] https://formapi.io/blog/posts/bitcoin-treasure-hunt/

I love these kinds of puzzles. Can't wait for the write-up of the solution.

Does anyone know how long this puzzle had been up?

At the very bottom of the site it says:

> Puzzle start: October 2 2018

Cool thanks. Seems like the puzzle was not difficult enough for the force of the internet?

The site says since October 2nd

To take this idea further... Wonder if it would be possible to click/mine-bait to alternative "branch" consensus :)

One can think of many better ways to harness human intelligence than work on an arbitrary puzzle... unless this is an interview for something much bigger.

I think it is really funny when people criticize something that is altruistic, but not altruistic enough for your tastes.

Are you going around saying "why don't these rich people stop buying yachts!".

At least this guy did something that wasn't entirely selfish. Which is more than can be said about most people in the world.

I actually have nothing against frivolous spending, since buying a yacht doesn't subtract from the high end talent pool. If you're going to put up a few mil to solve a math problem, why not something like P v. NP, or the Riemann hypothesis, or countless applied math problems. Instead it was spent on some kind of spectacle of arbitrary mental effort.

Come on. There already is a $1 million bounty on P vs NP.

Crypto people don't want P=NP though.

Should I assume you're also opposed to, say, logic puzzles, or chess?

> since buying a yacht doesn't subtract from the high end talent pool

What about all of those highly skilled technicians and engineers who dedicate years to building said yacht who aren't building rockets or faster trains for us all or designing better schools? Etc, etc...

Any argument rooted in "these other people should do X instead of Y because I think X is more important and want to see them do it" fails from inherent selfishness.

Whether X is indeed better than Y is moot.

"Whether X is indeed better than Y is moot."

Actually it's probably one of the most worthwhile questions, philosophically and practically. If this question doesn't get properly considered, we end up with blind glorification of activities whose main selling point is revenue generation and shitty feedback loops in society over generations.

> blind glorification of activities whose main selling point is revenue generation

Not inherently. Only in the cases where it's a true choice between something revenue generating, and something people are doing for social good.

Your perception of social good (people dedicating their time to intellectual puzzles you deem worthy vs people wasting their time on these meaningless displays of skill), is different to someone else's.

My point was perhaps too broad - but deigning to tell someone their pursuit isn't as worthy as one you think they should be pursuing is, frankly, pointless.

"My point was perhaps too broad - but deigning to tell someone their pursuit isn't as worthy as one you think they should be pursuing is, frankly, pointless."

That seems to assume immutable human values, and/or a postmodern view of the world. Promoting thoughtfulness about the meaning of human activity seems pretty valuable, regardless of the conclusion.

Thoughtfulness, yes, judgement, no.

Perhaps it's the medium of this discussion, but the reason your comment was downvoted was because it came across as judgemental and dismissive.

I've been CMO of a startup, and could spend my free time developing marketing plans for NGOs looking after sick kids to get them more donations, but I spend my talents and time watching arbitrary funny cat videos.

I know it's not the highest order use of abilities, but assuming people should only pursue what you deem to be the most worthy, and dismissing other pursuits, is a thought process so academic it's almost pointless to real-world discourse.

Hey, I'm not against recreational activities, everyone needs them to stay sane. It becomes different when an accidental bitcoin millionaire decides to put real money behind a meaningless task to watch someone else dance. At that point it stops being recreational for the problem solver, but rather a form of work.

Cogently dismissing other pursuits is an incredibly effective form of recruitment, so there's nothing inherently academic about it.

"Do you want to sell sugar water for the rest of your life, or do you want to come with me and change the world?”

Buying a yacht does subtract from a high end talent pool. It requires talented people to design and build a yacht.

High end is a very relative term. No doubt it requires talented people, but you don't see Feynman working on it.

Why is it so bad to have fun?

> I don't want to donate to charity (I have my own reasons for that, don't ask) but whoever cracks the code can do whatever he/she wants (including donating to charity).

I mean pretty much the only math that didn't come from arbitrary puzzle solving was that which was done for religious purposes, and that stuff powers pretty much all of modern society.

Religious purposes? I'm curious to know what you meant specifically. Metaphysics?

Geometry, calculus, set theory, etc.

In what sense was all that done "for religious purposes"?

The ancient Greeks developed a ton of geometry. I'm not sure how we could ever know for sure why they did it, but a clue might be in the name of the field: geo-metria, earth-measurement. (And it's known that some of them made use of geometry for practical purposes, or at least proposed doing so.)

Newton (so far as I can tell) developed calculus in order to do physics. Neither arbitrary puzzle-solving nor religion (though I'm sure Newton enjoyed solving puzzles and he was a religious believer).

Cantor certainly had some peculiar religious ideas that may have motivated his work on the beginnings of set theory. On the other hand, his first publication on the subject looks as if its goal is to provide a beautiful short proof of a theorem already proved by Liouville (on the existence of transcendental numbers); I suppose you could call that a "puzzle" on the grounds that everything in pure mathematics is puzzles, but I think Cantor would have viewed it as a practical application -- in the sense that it's useful for something else in mathematics. Puzzle-solving, perhaps, but not arbitrary puzzle-solving.

Bitcoin itself is all about mining arbitrary puzzles, there is really no more fitting way to give it away than this.

Applications are open for YC Summer 2019

Guidelines | FAQ | Support | API | Security | Lists | Bookmarklet | Legal | Apply to YC | Contact