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An Analysis of the Impact of Arbitrary Blockchain Content on Bitcoin [pdf]

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Re: An Analysis of the Impact of Arbitrary Blockchain Content on Bitcoin [pdf]

#51

Post by Tomte »

zeth___ wrote: post #30
dpwm wrote: post #23

Earlier quoted context omitted.

I'm reading this charitably as you saying that laws that criminalise distribution regardless of intent or knowledge need to be changed to recognise that with the internet people can effectively commit crimes without knowledge or intent. This is particularly relevant where distribution of material (child porn, terrorist material) is criminalised. This seems a really difficult area that's almost incompatible with the w…

>I'm reading this charitably as you saying that laws that criminalise distribution regardless of intent or knowledge need to be changed to recognise that with the internet people can effectively commit crimes without knowledge or intent. This is particularly relevant where distribution of material (child porn, terrorist material) is criminalised. No I am making the very simple case that a number is a number and you c…

All writing is just splinters of carbon or drops of ink.

How can an element or a wster-based solution be illegal?

Re: An Analysis of the Impact of Arbitrary Blockchain Content on Bitcoin [pdf]

#52

Post by oasisbob »

This gets close to something else I've been pondering lately - how to deal with immutable data structures in the realm of GDPR.

Recitations in GDPR require systems to be designed with privacy in mind. Immutable structures like the Bitcoin blockchain or Merkle trees in other applications would seem to be fundamentally incompatible with some GDPR privacy requirements.

Let's say Google receives a valid right to be forgotten request for an entry in one of their Certificate Transparency logs? Then what? I don't see how it can be dealt with without destroying the integrity of the log.

Re: An Analysis of the Impact of Arbitrary Blockchain Content on Bitcoin [pdf]

#53

Post by Tepix »

bb88 wrote: post #8
Moodles wrote: post #6

Some interesting graffiti on the bitcoin blockchain: http://www.righto.com/2014/02/ascii-bernanke-wikileaks-photo... I have always wondered this. What will a country do if someone embeds child pornography or a picture of Mohammed or something in the blockchain? Will it then be illegal to store the blockchain in that country? Is a link to such an image much different to an actual image? It seems hard to ever stop this…

> What will a country do if someone embeds child pornography or a picture of Mohammed or something in the blockchain? In the US at least, I'd hope that we probably wouldn't criminalize 1M people for the actions of 1. Hopefully in other countries they wouldn't do that either.

There is a possibility of a technical solution:

- You create a special rule for a block known to contain illegal data.

- The illegal data in the block gets NULLed. The other transactions are left untouched.

- The checksum for the next block is no longer calculated, instead it is hardcoded. This means there is no way of verifying the transactions in that block. Perhaps you add a new signature for the block with the NULLed data to make it harder to tamper with.

Once you start doing this workaround once you will probably have to do it repeatedly.

Re: An Analysis of the Impact of Arbitrary Blockchain Content on Bitcoin [pdf]

#54

Post by woah »

amelius wrote: post #34
zeth___ wrote: post #12

Earlier quoted context omitted.

I haven't looked for obvious reasons but back in the day people were saying that there was already child porn embedded in bitcoin: https://bitcointalk.org/index.php?topic=671894.0 Which is why child porn is one of the Four Horsemen of the Infocalypse: terrorists, pedophiles, drug dealers, and money launderers. That we are trying to apply flesh space laws to bits just goes to show how stupid we still are: https://en.w…

Note that we only need one number to capture all possible finite content (i.e., the number is chosen such that all binary strings will appear somewhere in the binary representation of the number). A "normal number" [1] satisfies this property. And it is believed that Pi is a normal number. [1] https://en.wikipedia.org/wiki/Normal_number

I’ve actually written a book on this topic: π

Re: An Analysis of the Impact of Arbitrary Blockchain Content on Bitcoin [pdf]

#55

Post by chaz6 »

ddalex wrote: post #35

So the obvious bit here is that an adversarial actor can poison the blockchain with bits that make downloading, storing and processing the blockchain a highly illegal act. This may have a chilling effect on participating in the network, thus reducing the number of nodes, and undermining the trust on the blockchain and in the coin because the reduced requirement of computing power needed to mutate the blockchain. Acco…

I thought the same thing about PGP/GPG keyservers. They are supposed to be immutable so if someone uploaded a key containing a jpeg attachment depicting illegal content, the only course of action would be to wipe every server in the network.

Re: An Analysis of the Impact of Arbitrary Blockchain Content on Bitcoin [pdf]

#56

Post by omginternets »

zeth___ wrote: post #19
martindale wrote: post #16

Title is sensationalism. Actual paper title is "A Quantitative Analysis of the Impact of Arbitrary Blockchain Content on Bitcoin" — see also Illegal Numbers [0]. [0]: https://en.wikipedia.org/wiki/Illegal_number

The paper isn't wrong though. There are supposedly numbers that correspond to illegal jpg images in the bitcoin block chain.

> There are supposedly numbers that correspond to illegal jpg images in the bitcoin block chain.

How did they come about? Do you have a source for this?

Re: An Analysis of the Impact of Arbitrary Blockchain Content on Bitcoin [pdf]

#57

Post by bluesign »

cstross wrote: post #36
rogual wrote: post #33

Isn't intent generally a big deal in law? If I argued that your innocent MS Word doc was illegal because it decoded to child abuse images under a special encoding scheme I just made up, I'd be laughed out of court, and rightly so. It's technically true, but irrelevant. No crime was committed. Doesn't the same principle apply here?

In the UK (and, I believe, the USA) child pornography is a "strict liability" issue — intent is irrelevant, mere possession is itself illegal. This is how teens get nailed for receiving unasked-for sexts from their under-age-of-consent SO. As with illegal drugs and, in the UK, unlicensed firearms, this means the prosecution doesn't need to prove intent. (Mandatory — usually harsh — sentence terms are usually part of…

But we are talking here about not exactly "possession". Imagine I sent you a funny video, but somehow, I appended it with child pornography image, which your video player will easily skip, unless you are specifically looking via forensic measures.

Re: An Analysis of the Impact of Arbitrary Blockchain Content on Bitcoin [pdf]

#58

Post by CamTin »

elmar wrote: post #31
jwilk wrote: post #5

Abstract: Blockchains primarily enable credible accounting of digital events, e.g., money transfers in cryptocurrencies. However, beyond this original purpose, blockchains also irrevocably record arbitrary data, ranging from short messages to pictures. This does not come without risk for users as each participant has to locally replicate the complete blockchain, particularly including potentially harmful content. We…

"illegal pornography, can render the mere possession of a blockchain illegal." I see this as a very strong legal attack vector on full nodes and cryptocurrencies, probably a way around it, is to only allow meta information on a cryptographic form, even then the owner can publish the view key publicly. A drastic solution is to just prune or don't even allow metadata.

You don't even need the ability to record metadata on-chain to encode arbitrary data. An agreed-upon method of encoding it into ordinary transactions is enough. Even if BTC-style transactions were just inputs/outputs (they're not), you could still encode information down into the satoshi-place of the inputs or outputs themselves. It's even worse for something like Ethereum: essentially the whole point of that blockchain is to encode abritrary (executable) metadata in the form of the contracts themselves.

Re: An Analysis of the Impact of Arbitrary Blockchain Content on Bitcoin [pdf]

#59

Post by throwawaylolx »

omginternets wrote: post #56
zeth___ wrote: post #19

Earlier quoted context omitted.

The paper isn't wrong though. There are supposedly numbers that correspond to illegal jpg images in the bitcoin block chain.

> There are supposedly numbers that correspond to illegal jpg images in the bitcoin block chain. How did they come about? Do you have a source for this?

Thats's precisely what the paper linked in the OP describes?

Re: An Analysis of the Impact of Arbitrary Blockchain Content on Bitcoin [pdf]

#60

Post by zeth___ »

Tomte wrote: post #50
zeth___ wrote: post #44

Earlier quoted context omitted.

You are extremely hostile and unhelpful in this discussion. If you want to drag discourse down there are a lot of other forums where one line replies signaling you know something profound without actually saying anything are acceptable. HN is not one of these.

You should simply read the essay and educate yourself. Obviously you won't, but don't act so high and mighty. Especially since "illegal numbers" has been the standard argument of people with lots of opinion and little knowledge. BTW, massively editing and expanding your comment after a reply without any notice is shady.

You are continuing to be hostile.

I have read the paper, years ago.

His point about 'colour of bits' is conflating a number of different ideas. A chain of trust and intent for starters.

A chain of trust is a trivially easy thing to solve: https://en.wikipedia.org/wiki/Chain_of_trust

Asking that bits meet some simple predefined function isn't hard. In his example simply demanding that along with the substance you are provided a signed copy of the ph value would mean that bits without color give us all the information we need, given the physical limitations of the universe as we understand it.

Intent isn't. But intent has nothing to do with the bits either. Which has been my point from the start: no digital information should be a priori illegal.

On the edit: I finished it before your post. I'm not sure how long a line took to write, but I suspect it was way less than the time needed to refresh the thread.

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