
Child abuse images hidden in crypto-currency block chain - adzicg
https://www.bbc.com/news/technology-47130268
======
blincoln
Possession of this type of image is a federal crime in the US.[1] When I took
a digital forensics course about five years ago, we were told that if we ever
discovered any on a system we were investigating, it needed to be reported to
the FBI immediately or we could also be charged.

If someone does this in a way that goes unnoticed, and it's discovered after
long enough that rolling back is impractical, does that effectively kill the
blockchain where the data is embedded, at least as far as the US and countries
with similar laws are concerned?

[1] [https://www.justice.gov/criminal-ceos/citizens-guide-us-
fede...](https://www.justice.gov/criminal-ceos/citizens-guide-us-federal-law-
child-pornography)

~~~
Tepix
Related:

What's the smallest piece of data that qualifies?

Can a 16x16 image be illegal?

What about a 64x64 image?

What's the situation like if you have two chunks of data (perhaps at two
separate locations on the blockchain) and only if you XOR them you get the
illegal image?

~~~
claudiawerner
Like most things, there isn't a magical number, and the notion that there
should be (or that there is, but not codified) is a dream that tech people
would have to imagine how the world works. They think they outsmart the law
with various technicalities and hypothetical solutions - but in the end it
comes down to a judge's interpretation, and no amount of "well actually"ing
will get you around that.

So you might think "a 16x16 image can be illegal?! ridiculous!" \- well tough,
the law doesn't care about how many pixels the image contains, despite a
hacker's incredulity.

~~~
klipt
Well as a non pedophile I have no desire to possess child porn, but I also
don't want to be framed or blackmailed over innocent data that becomes illegal
under some technicality like "when xor'd with the blackmailer's carefully
constructed data this becomes child porn" \- because the latter could happen
to anyone?

~~~
claudiawerner
That's an issue that's mostly irrelevant to the law, though. Even if you were
to receive XOR'd data (or something encrypted), simple possession wouldn't be
illegal if you reasonably weren't aware that it could be interpreted that way,
or (as someone else pointed out) at least in the UK you didn't have the
"knowledge or tools" for such a decryption. Intent obviously matters here,
among a host of other factors. That was really my point all along - viewing
this as detached from the actual workings of the law and situations is a fun
mind game for hackers, but is ultimately irrelevant when it comes to human
judges interpreting human laws.

------
giornogiovanna
> He said there was "ongoing research" to find ways to remove such content
> from block chains but these were "not yet mature".

Either you have centralization, which nobody wants, or you have a bot that
everyone agrees on to censor things, and people will will always find ways
around bots. Are there really any other alternatives?

~~~
mayniac
The easiest solution is probably just limiting how much data you can add to
the ledger. There's no real reason why people need to add more than 10kb of
information to a transaction. Cryptocurrencies aren't meant to be image
hosting platforms anyway.

~~~
kennywinker
Images can be split into 10kb blobs...

~~~
mayniac
Then there's also a million other ways to store or transmit images if you use
tiny segments. Encode the image in base64 and you can use Twitter, reddit
comments, SMS etc.

The point is to make it unfeasibly hard to store/send the images, not
impossible.

------
AdmiralAsshat
Aren't we getting back to the hypothetical question that any image, digitally
encoded, would theoretically exist at some index of any infinite number (e.g.
Pi), given enough digits? Is the possession of Pi then illegal?

~~~
giornogiovanna
Very far-off digits of π (assuming π is even a normal number) are not easily
accessed or enumerated. In fact, you'd probably need more information to
encode the index and length of your sequence than you would to just write the
data out. In contrast, a block chain is easily downloaded and traversed,
indices are small, and most importantly, there is a very, very obvious intent
to distribute illegal content. I don't think that these situations are
comparable.

~~~
saltvedt
"The Bailey–Borwein–Plouffe formula (BBP formula) is a spigot algorithm for
computing the nth binary digit of the mathematical constant π using base-16
representation. The formula can directly calculate the value of any given
digit of π without calculating the preceding digits. (...) Though the BBP
formula can directly calculate the value of any given digit of π with less
computational effort than formulas that must calculate all intervening digits,
BBP remains linearithmic (O(n log n)), whereby successively larger values of n
require increasingly more time to calculate; that is, the "further out" a
digit is, the longer it takes BBP to calculate it, just like the standard
π-computing algorithms."

[https://en.wikipedia.org/wiki/Bailey%E2%80%93Borwein%E2%80%9...](https://en.wikipedia.org/wiki/Bailey%E2%80%93Borwein%E2%80%93Plouffe_formula)

------
momentmaker
So, the easiest for the government to destroy blockchain is to supplant their
own illegal images onto the blockchain themselves...

~~~
21
No, the easiest for the government to destroy blockchain is to just declare it
illegal.

~~~
jMyles
Do you seriously think that will be effective? Have you never heard of
marijuana?

~~~
21
Well, in that case embedding child porn on it will not help either, would it?
I was just highlighting the massive fallacy of parent.

~~~
jMyles
I think that attempting to pretextually take action based on some threat (and
let's be honest, "think of the children" is one of the primary vectors for
this) is more likely to curry political favor (and provide political cover)
than mere censorship.

So yes, I think that embedding illicit material is a more likely tactic than
prohibition. The latter - because it will be such a colossal failure - will
only serve to show the state's inability to control the internet, and that's
exactly what the state is trying to hide right now.

~~~
21
To use your own argument, "child porn being illegal didn't work for stopping
child porn, did it"?

The second huge fallacy (you are also making it) is that the government wants
to ban crypto, but is afraid of saying it and comes up with all kinds of
contrived tactics.

~~~
nickelcitymario
> The second huge fallacy (you are also making it) is that the government
> wants to ban crypto, but is afraid of saying it and comes up with all kinds
> of contrived tactics.

"Government" is a term that covers an awful lot of groups with differing
agendas.

Law makers make laws. But "government" includes spy agencies, law enforcement,
central banks, competing political actors, as well as just rogue individuals.

Making cryptocurrency illegal would require having some degree of popular
support (which maybe they would have).

One dude with an agenda, though, could poison the blockchain with a single
image. And that one dude (or dudette... i shouldn't be so close minded) could
very well be a high-ranking member of a government agency of some sort.

To be clear, I'm not suggesting there's any evidence for this. Just that it
doesn't seem entirely unreasonable to consider the possibility.

------
jasode
The inevitability of "defacing" the blockchain was discussed back in May 2017
as well:
[https://news.ycombinator.com/item?id=14434786](https://news.ycombinator.com/item?id=14434786)

Global public blockchains are too tempting a target for that type of thing. It
will interesting to see how this plays out and whether government agencies
respond (or ignore it).

~~~
bilbo0s
> It will interesting to see how this plays out and whether government
> agencies respond (or ignore it)...*

I don't think I'd count on government agencies ignoring child abuse images.

------
wolco
This makes me think. Any data in a certain form could be used to generate an
image.

What if someone added data in a form that only later after a viewer appeared
will it reveal this type of content. This would make any system with that data
immediately illegal.

Looking down the road what it was encoded in dna would it be illegal for
someone to read another person's dna?

If someone had a tattoo on there face of one of these images would security
cameras need to wipe any data caught?

~~~
Tepix
Remember that every imaginable image is also somewhere in the digits of pi.
You "just" have to find it. Does that make the number pi illegal? I guess not.
Does it make programs illegal that can calculate those digits of pi? Doesn't
sound reasonable, does it?

~~~
lalaland1125
This analogy to "storing information" in the digits in pi is simply incorrect.
The reason why it's incorrect is that in order to "store information", your
access key must by definition be smaller than the data you are storing. This
is not the case for "hiding" things in the digits of pi. In general, the index
offset needed to find something will have more bits than the target
information. This is clearly not the case for storing information in a
blockchain as you only need a small index to find the transaction.

------
shiado
Given any arbitrary stored sequence of bytes, one can always devise an
algorithm which converts those bytes into other meaningful sequences of bytes.
This is interesting because it would appear that the liability of possessing
CP on the blockchain is dependent on the ease of converting those bytes into a
meaningful sequences of bytes of an image file, but where does it stop? Do the
bytes have to be a raw sequence of exact image bytes stored contiguously? Does
simply flipping the bits make the byte sequence lose enough 'meaning' to get
rid of liability? If one requires the bytes alone to have the 'meaning', then
what about image compression and the associated algorithms? There are some
heavy-duty thought experiments with this type of problem that the courts are
probably ill-equipped to address.

------
t0astbread
I have multiple questions.

> In addition, Money Button has banned the user that uploaded the material.

> It has also put in place filtering systems to spot when anyone tries to
> upload similar content.

> "We have all the information we need to track down criminals and prosecute
> them."

Doesn't blockchain technology exist to prevent censorship and provide
anonymity (in terms of not being able to link transactions to a real life
identity)? So why would anyone want to use a client that collects and stores
this kind of information about them? Doesn't it (almost) completely erase the
point of having a blockchain in the first place?

And how is this case handled now? Money Button said they forwarded the
identity of the uploader to the authorities but is anyone gonna do anything
about the problematic data?

------
tivert
So, possession of the Bitcoin blockchain is now illegal, according to the laws
of most developed countries.

~~~
Hello71
This is "Bitcoin Satoshi Vision", which is completely different and appears
from a quick Google search to be completely irrelevant.

~~~
afgkonionio
Of course it's completely irrelevant. It's a cryptocurrency.

For a cryptocurrency, it's relatively important. It's not one of the big boys,
but it's supposedly worth $1 billion.

------
bluewavescrash
How do chains which value absolute immutability deal with this? Such as
Ethereum Classic.

~~~
gsich
They don't.

------
Sir_Substance
Ah, this old chestnut.

So from the last time this came up: [https://thebitcoinnews.com/no-there-isnt-
child-porn-on-the-b...](https://thebitcoinnews.com/no-there-isnt-child-porn-
on-the-bitcoin-blockchain/)

With the important bit here:

 _80 bytes is all that OP_RETURN can store, and what’s more that information
is subject to deletion. That’s because bitcoin nodes are capable of pruning
“provably unspendable” UTXOs for efficiency, which include OP_RETURN data._

TL;DR the last time the schadenfreudists were looking for something to point
and laugh at on this front, they didn't understand the technicalities of what
they were talking about _at all_.

This BBC article makes an interesting claim:

 _" In January, the amount of data that could be added to the BSV block chain
was increased significantly._

 _Before that, people could generally add only short chunks of text or web
links to the block chain._

 _But now it is possible to add full images in an encoded format. "_

I've never heard of this BSV coin before, so I don't know the details of this
change. Assuming it's a fork of bitcoin and all they did was increase the
allowable size of the OP_RETURN, this will once again be sensationalist
reporting with no substance. I'd imagine the first thing BSV nodes would do is
prune the OP_RETURN garbage because who wants to be paying the storage cost of
other peoples embedded images?

But hey, the BBC article is extremely light on details. Maybe this is
something that can't be pruned so easily? Does anyone know?

~~~
detaro
Following links from the article:

[https://blog.moneybutton.com/2019/01/26/how-we-added-
support...](https://blog.moneybutton.com/2019/01/26/how-we-added-support-for-
giant-op_return-data-in-money-button/)

[https://www.yours.org/content/the-unfuckening-of-
op_return-b...](https://www.yours.org/content/the-unfuckening-of-
op_return-b10d2c4b52da)

" _We’re about to take the red pill and see how deep the rabbit hole of on
chain data storage really goes. Tokenized is ready for this, yours.org is
ready for this, @_unwriter and his plethora of tools are ready for this as are
others. Calvin Ayre has previously spoken of the ‘Cambrian explosion’ of
creativity and I believe that unbounded-by-anything-except-fees data storage
will be a key trigger for this._ "

~~~
Sir_Substance
Yep, so it is OP_RETURN and therefore can and will be pruned.

------
ilikehurdles
BSV is, apparently, yet another bitcoin fork — it’s a 4 month old Chinese
bitcoin fork with 1 released version and a very vague website[1]. BBC does not
explain at all how this differs from Bitcoin or the relevance of this coin.

[1]: [https://bitcoinsv.io](https://bitcoinsv.io)

~~~
bdcravens
It’s principally backed by Craig Wright (Australian with dubious claim of
being Satoshi, original creator of Bitcoin) and Calvin Ayre (investor born in
Canada). I wouldn’t categorize it as Chinese (Bitcoin Cash/BCH is probably
better categorized that way, being backed by Bitmain)

~~~
ilikehurdles
Thanks for the correction. I was assuming going off the Chinese flag on their
site and the vague descriptions.

------
decentralised
This is old news.

[https://www.dailydot.com/business/bitcoin-child-porn-
transac...](https://www.dailydot.com/business/bitcoin-child-porn-transaction-
code/) (2013)

[https://news.bitcoin.com/no-isnt-child-porn-bitcoin-
blockcha...](https://news.bitcoin.com/no-isnt-child-porn-bitcoin-blockchain/)

[https://www.wired.com/story/why-porn-on-the-blockchain-
wont-...](https://www.wired.com/story/why-porn-on-the-blockchain-wont-doom-
bitcoin/)

------
clarkmoody
People were worried about this in 2011. I haven't heard of any doors getting
kicked for having a copy of the blockchain.

------
miguelrochefort
This is why data regulation will never work. GDPR and Copyrights included.
Nothing can be done about it, short of banning blockchains.

------
21
> _Returning to our analogy, the publisher of a best-selling book might
> announce that the first letter of every line in the book can be interpreted
> as a sequence of pixels that represents a pornographic image of a child. Can
> the police then arrest owners of the book? Common sense suggests that the
> answer is no, and most lawyers would agree._

[https://www.wired.com/story/why-porn-on-the-blockchain-
wont-...](https://www.wired.com/story/why-porn-on-the-blockchain-wont-doom-
bitcoin/)

------
aboutruby
So is it going to be illegal to have the full blockchain data? That could
prevent a lot of miners from operating

