Surprises in the Bitcoin blockchain and how they are stored (2014) | Hacker News Reader

Surprises in the Bitcoin blockchain and how they are stored (2014)

righto.com

106 pointspicture70 comments

Well, we must be careful about what goes into blockchain. I've once publicly announced my love for my geeky GF in the transaction data of my Ethereum transaction, which was cool at the time...

Then we broke up.

For future reference, issues like this can be avoided by using “event” rather than “fact” semantics. The data published on the chain is a fact “can16358p loves girlfriend” which doesn’t imply any time window. An event semantic of “can16358p loved girlfriend” would have made this much less confusing, and in this case something akin to a certificate expiration with frequent renewals might have helped.

Simply find a new girlfriend who hates the blockchain.

While it's a great solution to the particular issue, I don't think I'd personally get along well with a girl who hates blockchain.

Ah, I only get along with girls that hate the blockchain :)

Did you at least update your relationship status, or were you dating long enough for the transaction fees to have gone up enough to make that unreasonably expensive? ;P

Could be worse, you might have gotten a big tattoo

Tattoos can be removed these days :p

edit: this is not a value statement about blockchains

And isn't that just great? In order to verify my $1 payment to McDonalds all we have to do is acknowledge that can16358p loved his GF once. \s

I think no needing to store the whole chain while also not relying on verified shards or trusted peers will be a major breakthrough for BC-Tech in the future. Mina looks promising in that regard.

can16358p paid for tx fees when the tx was mined. from that perspective that data should be there and even contributes to the network security. you too can write crap to the blockchain.

Still remember that years ago, before the bitcoin core client started to obfuscate on disk data, people mined transactions with EICAR as data and that got picked up by AVs

You already don’t need to. State is a merkle tree. https://eth.wiki/concepts/light-client-protocol

There are some that claim that the distributed PGP keyserver system is intrinsically illegal under the GDPR because there is no way for a user to remove the personal information they might upload there. The system is distributed and is append only. You would have to get every single server operator to agree to update the data at the same instant which obviously is impractical. People have actually taken down servers based on this idea.

Blockchains would be just as illegal. So if you are in the EU you could try requesting that Ethereum be taken down under your right to remove your personal data from a database.

How would anyone just “take down” ethereum?

If the EU actually wanted to "take down" ethereum then they have a few avenues they could take.

I think it is technically already illegal for EU citizens's data to exist on non-EU blockchains, so a legal cryptocurrency could only exist within the EU or any country with a data-sharing agreement (which I do not think currently includes the US right now).

So just listing things they could do:

Make it illegal to host the data/be a validator would relegate crypto to something that is only used for illegal purposes.

Write into law that GDPR still applies to blockchains, the validators cannot stay anonymous so they either remove the data from the blockchain or get police knocking on their door.

Any other use that this would be illegal so could never be used for anything legal inside the EU, lowering it down to a similar priority as piracy, being effectively neutralized, aka not affecting the majority of EU citizen.

You can make up all the laws you want, you aren't blocking access to eth.

Not many ways you can convert crypto into money if the banks aren't in on it, or allowed to be in on it.

But for every other use of ethereum it is definitely harder to block, not that there are very many other uses right now.

And EU could just block those NFT trading websites, making it all annoying enough to use that most non-super enthusiasts wouldn't bother, because while you cannot completely block something, you have effectively succeeded if the vast majority of your population cannot be bothered.

I actually ran into this issue when designing an "audit" store service recently. Basically, we had a need to store when certain transactions happened by users on a platform, so that they could later be audited if necessary. My first reaction was to use a blockchain-like append-only database. Perfect, until we realized we _also_ had to honor GDPR requests of users, and therefore had to be able to remove data...

I wonder how the saving of user names and email addresses into Git repos (which is a similar hash chain) interacts with things like the GDPR.

It's impossible to remove a person's personal identifying information from a Git repo without completely rewriting it.

I imagine it's covered by some kind of legitimate interest clause, but I have no actual idea.

Announce your breakup in another transaction: "I no longer love my geeky GF".

Next time I'll make a smart contract that I can invoke to change feelings.

Might be a good Solidity tutorial.

Not a problem: just treat your love as NFT.

My immediate thought is that this can be abused: to store revenge porn, inflammatory comments, defamation, and so on, in a way that is more "permanent" than the way this stuff is usually stored online.

Is that a valid concern, or no?

It's an attack I've contemplated. If you started sending a whole bunch of plain text Tiananmen Square remembrance stuff you'd very quickly have China cracking down on whatever it was.

An image of tank man is already embedded in the blockchain.[0]

CSAM links are there too.[1]

[0] https://www.reddit.com/r/Bitcoin/comments/rbxupy/tankman_ima...

[1]

> Bitcoin’s blockchain contains at least eight files with sexual content. While five files only show, describe, or link to mildly pornographic content, we consider the remaining three instances objectionable for almost all jurisdictions: Two of them are backups of link lists to child pornography, containing 274 links to websites, 142 of which refer to Tor hidden services. The remaining instance is an image depicting mild nudity of a young woman. In an online forum this image is claimed to show child pornography, albeit this claim cannot be verified (due to ethical concerns we refrain from providing a citation). Notably, two of the explicit images were only detected by our suspicious transaction detector, i.e., they were not inserted via known services.

https://fc18.ifca.ai/preproceedings/6.pdf [SFW]

Maybe this explains PRC's new hard-line anti-Bitcoin stance (over the last year).

Yeah, that's definitely it. I can't think of any other reason.

I can think of a couple.

I doubt that, because there’s no easy way to browse or view content on the blockchain. Someone could make a website to view blockchain data in a human-readable way, but that’s…just a normal website that can be taken down or censored as easily as any other. And of course, there are undoubtedly much, much easier ways for someone living in China to find information about the Tiananmen Square protests.

It has been already done on Binance Smart Chain that is not very centralised (Chinese devs are essentially in control):

https://thedefiant.io/tiananmen-contract-on-bsc-seeking-to-p...

I regularly do that to dissuade mainlaind "fatten the pig" scammers..

That or "pretend" communicating as a CIA spook, pushing weapons into china, contacting his contact. Hope they invite those crooks to drink tea..

In the engineering sense this has already happened.

I'm not sure "abused" is the correct term, though. It's an immutable data store, like IPFS with a server in a jurisdiction you don't control. It stores data.

Is it "abusing" ext4 if you use it to store a movie rip?

I would say it's pretty clear cut that this is abuse in a different way than ext4 because the blockchain has a format for how it stores various fields and you store data by putting different data in those fields. For example the fake addresses to which they send bitcoin to generate transactions.

It's also worth thinking about how this is used in the context of leaking data. Imagine if instead of posting Jennifer Lawrence's nudes on reddit, hackers had put them on the blockchain and just told people it was there. You now have an immutable copy of those photos stuck in a billion dollar speculative asset.

I agree that Bitcoin wasn't explicitly designed to store data.

It was, however, designed to be uncensorable. Your second sentence there is - well, indeed. It _is_.

Or worse, all the nuanced forms of a dead man's switch.

[0] https://www.wired.com/2013/07/snowden-dead-mans-switch/

[1] https://www.reddit.com/r/OutOfTheLoop/comments/58nn58/what_h...

[2] https://sarcophagus.io/

"Worse" in what way?

To me that sounds beneficial. I'd do it myself if I had some blackmail on someone!

Until that someone turned out to be a nation-state, case in point the still-ongoing story of J.A.

I would say it’s physically impossible to restrict what an individual can do, regarding basically anything, without severe restrictions in freedom. However you can make fierce penalties for entities and organizations that promote, advertise, profit, etc. from actions which has a tendency to reduce it happening.

For example it is trivially easy to film the TV at a bar, then tweet out the video of a sports game - millions do it every day. But if a company did that without the rights and earned money from it - an easy lawsuit.

The issue is that the damage here is almost irreversible - short of taking the whole blockchain down (which might be used as an excuse to do it ?).

I guess that the penalties could be correspondingly high - like the difference between rendering someone temporarily unconscious versus killing them ?

Yeah, and there's the difference - putting it on a blockchain is incredibly permanent, and might not be easily attributable to a person.

In these cases the miners and the orgs who run the blockchains are the vulnerable parties hosting the content. I suspect it flies below the radar for enforcement mostly because offending material is basically there as a stunt rather than a place used for active proliferation. In the same way Roblox is full of IP infringement.

Yes it's a very valid concern. And you don't even have to go into porn territory, if the blockchain containans personally identifiable information, and it does, then it's probably in violation of the GDPR in the EU.

Immutable data is almost never a good idea in practice.

This reminded me of Keybase where they signed and published [0] their root Merkle tree to the Bitcoin blockchain, as part of their server security mechanism. It was an ingenious idea at first until when it came to signature revocations. Even though they have the mechanism for that too, the data itself is still stored onto the blockchain forever with no "garbage collection" on deprecated data, outside of Keybase's control.

[0] https://book.keybase.io/docs/server/merkle-root-in-bitcoin-b...

[1] https://keybase.io/docs/server_security/merkle_root_in_stell...

If the article wasn't as old as it is (almost eight years), I'd take it as a given that the author deliberately omitted a whole lot of things that might put BTC in a bad light. Considering that even in 2014 the days of whole-number BTC amounting to play money had long been over, I wouldn't be surprised if there was self-censoring due to being personally invested even back then (but I wouldn't have suspected it back then)

I'm somewhat offended by your comment. For the record, I did not deliberately omit things that would put BTC in a bad light. I was not personally invested in Bitcoin (beyond a dollar or so for experiments). I wrote plenty of things negative about Bitcoin, enough to be disliked by part of the community.

I don't see why bitcoin nodes would be immune to DMCA takedown notices or other legal remedies. Sure it'd be a pain and (so far) not usually worth the hassle, but it'll have to come up eventually right?

What's that? It's impossible to take down a block without messing up the entire blockchain? Well maybe Mr. Bitcoin should have thought of that when making the data so disturbingly entangled!

A massive, multi-national takedown across the planet for 12k nodes? Thats well beyond the DMCA

I can only imagine the cost to do that

Would you have to do that or would putting the squeeze on nodes in jurisdictions you could reach be enough? Not complying comes with a cost so presumably they would ultimately be forced out or to convince their peers to fork.

extra-territorial enforcement?

would you personally enjoy taking orders from China, or whoever the next global hegemon happens to be?

Isn't it great to have some very remote and entirely unaccountable overlord telling you what to do, and then prosecute you criminally on a whim?

Sounds like utopia.

It's not extra-territorial if you have agreements in place, quite a lot of countries have treaties like this.

In any case I explicitly said within their jurisdiction. Meaning you'd go after the nodes in your country or with agreements in place. For example there was a news story the other day about miners maybe setting up in Texas (despite the creaking grid) they'd probably be vulnerable to enforcement of things like the DMCA.

Or just like America.

two wrongs dont make a right.

america should stop doing that.

If you could store Pi (3.14159..) with all its digits on your computer, it would contain all past and future revenge porn. I wouldn’t really make anything of it but I wonder what a judge might want to do.

People throw this claim around, but note that:

1. It's only theorized that pi has this property.

2. Storing the starting index of the digit would likely be larger than any computer right now can hold, and possibly bigger than the estimated number atoms in the universe.

3. What a judge cares about is that you used the number with the intention of accessing the file, not the particular sleight of hand method by which you accessed it. If you cheekily share your favorite number that just so happens to be the starting digit index for "Limp Bizkit - Nookie.mp3", that's what the judge cares about. No need to outlaw pi, no need to outlaw numbers, it's all about intent. That's why they're called judges. They judge people and their intentions.

A number that provably contains all finite bit patterns is

X = . 1 10 11 100 101 110 111 0000 0001 ...

(the binary version of Champernowne's constant [1]) but the index at which any pattern occurs takes more bits to write than that pattern itself, and the same would hold (on average) for patterns in pi, assuming it actually is normal.

[1] https://en.wikipedia.org/wiki/Champernowne_constant

If true then the index of the data would be the file. That's called encryption.

That's not a good faith response.

Show me the digits of pi that contain the image of Nelson Mandela that is as easy to find as the one described in this article.

Show me a way to take any random arbitrary image and find it's corresponding representation in pi that is as easy as encoding that same image into the blockchain.

I am not making any claims about digits of pi, however, one can take an arbitrary bit string (eg: an image of Nelson Mandela's representation), treat it as a number and extend its digits to generate a prime number or a perfect power. See: https://www.ias.ac.in/article/fulltext/reso/015/10/0941-0947

So, one could in theory create a list of primes (or perfect powers) populated them with hidden content using the aforesaid method and claim they are only a list of primes (or perfect powers).

Show me a way to take any random arbitrary image and do the calculation you discuss, and share the output, that is as easy as encoding that same image into the blockchain.

https://github.com/ajeetdsouza/pifs

A few years ago I wrote some toy code to scan for raw texts stored on Ethereum. Some were interesting to read. See below (the way to read: expand "click to see more" -> "Input Data" -> "view input as" - select UTF8)

* A (a bit creepy) love letter https://etherscan.io/tx/0xee30531afa6147ce450d9404bcc3fb9758... * A Chinese student activist's open letter (some media reported about it at the time) https://etherscan.io/tx/0x2d6a7b0f6adeff38423d4c62cd8b6ccb70...

Damn, for anyone trying to replicate this: the transaction cost of the love letter would be around $2500 today.

It would be $700 the link literally tells you that. And you could do it for much cheaper by just lower the gas cost. They used 900 gwei, you can get a transaction through most days for 90 gwei. Right now you could do it for 165 gwei.

This is a bit above my paygrade but I think this type of transaction doesn't depend on any state, so you can expect it to succeed even if it gets mined a few days after you submit it?

If so you could just set the gas price to 50 gwei and wait.

  Hello Qiu Shifu, hello world.Do you know? We appeared to be cool and smart when we first met. The truth is, we are both childish and stupid (in a good way). We do not know each other for very long, but we get use to each other faster than light. We think alike. We have similar minds. We know what the other wants without much asking. We make fun of each other. We make fun of the blockchain. We make fun of the world. Yes, you and me are fun-making-massive-attacks terrorists. Who are you? I remember you elegantly spilled strawberry milk out of your mouth on a bullet train from Shanghai to Beijing like my young sister. You asked me to conduct pyramid schemes with your twinkling big beautiful eyes. You encouraged me to travel to India and North Korea like a Hajid encouraging his fellows. You and me climbed up the tallest chimney in 798 factory trembling like a spring chicken. You woke me up and asked me to run with you and enjoyed Jian Bing Guo Zi for breakfast. You are so abnormal, and I enjoy doing all these with you. What are you? You are a very smart thinker and you are smart enough to do anything be it investing to marketing. You dreamt about being an artist and I think I will be your broker. You are always full of beautiful passion and dreams about the world and I wish they will all come true. No, they are coming true.  You are so cute, and I think nothing else can be even as close to your cuteness.Your eyes are more beautiful than the most beautiful lakes. I do not only want to stand on the tip of your nose and dive into the water, I want to be the pisces that swim in the water forever, one fish in each of your eyes. Out of the water, I die. Here and now, on this Ethereum Block, I am ledgering on the network just to tell the entire world how lucky I am to have found the most astonishingly adorable woman since I am a very normal grown man with barely basic programming skills. You fascinate and inspire me. You influence me for the better. You re the on my top list, you are the objective of my objective, like an angel that rescued my stupid lonely soul in David Tao s songs; and at the same time like a cult religious leader running pyramid scheme that takes my ass for sacrafice and I can never say no, and instead I recklessly offer you my properties, passion and love. For every minute that I have been with you, it is full of happiness and joy. Can I have so more of this in the rest of my time? More minutes, more hours, more days, and even years? There is only one solution to that problem. You, be mine. O shifu

You exposed another comment's love letter to HN!

Fascinating way to make a puzzle for people, post a digital message for someone to stumble upon, or make a tribute. This was from 2014, I wonder if someone has posted a follow up.

If anyone wants to explore this by themselves, I wrote a few years back a library to help: https://sr.ht/~pierrenn/barkaelogy/

https://eternitywall.it/about/

This looks interesting; any clear tutorial or explanation on how they did this?

I didn’t see one, but they posted code extracted from the blockchain that can extract existing and write new data.

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