
Blockchains Never Forget - sergeant3
https://www.ribbonfarm.com/2017/05/25/blockchains-never-forget/
======
skybrian
You don't need a blockchain for this. A commit to the Linux kernel, once
accepted, practically will never be removed from history, since it's been
copied so widely and would require so many people to agree.

And isn't this also how ordinary accounting systems work?

The place where it breaks down is that Bitcoin is for anonymous people who
don't trust each other. With fraud there is no forgiveness.

In many other systems, people are not anonymous and mistaken transactions can
be reversed, using the court system if it comes to that.

~~~
hdhzy
The difference is Linus won't take your arbitrary data and persist it in the
kernel's history and Bitcoin will for a small amount of money. This makes some
interesting schemes possible to implement: timestamping, proof-of-existence
and similar services. For example Keybase.io uses Bitcoin like that to prove
that are not messing with people's data [0]. Another interesting use is
creating virtual tokens via Counter Party [1].

If you don't want to pay you also "abuse" Certificate Transparency logs to do
basically the same job, just like Mozilla with their Binary Transparency [2].

[0]:
[https://keybase.io/docs/server_security/merkle_root_in_bitco...](https://keybase.io/docs/server_security/merkle_root_in_bitcoin_blockchain)

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

[2]:
[https://wiki.mozilla.org/Security/Binary_Transparency](https://wiki.mozilla.org/Security/Binary_Transparency)

------
jasode
To my knowledge, the scenario hasn't happened in real life yet but it's a
thought experiment that tests (abuses) the permanence of an un-erasable
consensus ledger. I will try to use the most distasteful data I can think of
to drive the point home...

Imagine that a vindictive person embeds the bytes of a graphic explicit child
rape video into the ledger. _All subsequent blocks_ will depend on those "bad
bytes" so they can't be erased. For the later blocks to be trusted, _everyone_
must have a copy of those bytes.

What is society's response? Live with those bad blocks to maintain the trust
in the chain? Or does a majority agree to fork a new chain (ala Ethereum/DAO)
that removes the bad bytes?

Even if a fork happens, the trolling/defacing of bad bytes into the worldwide
blockchain is a tempting method to force everyone to have a copy of your
"graffiti". The new fork would simply be a new target to deface. A smaller
example of "bad bytes" is doxing someone's Social Security # or home address.
(For all we know, some of the transaction amounts in some Bitcoin blocks may
represent "bad bytes" but nobody has made the knowledge public yet to ruin a
person's life. E.g. Bitcoin block #403891 has Jennifer Lawrence's SSN#.)

In essence, the _permanence_ of the block chain can be used as a weapon
against it. It doesn't mean the blockchain concept is unusable but there
doesn't seem to be an easy computer-science answer for it.

~~~
RichardHeart
Evil and horror will always be just around the corner if you wish to see it.
Trying to cripple technology to force forgetfulness upon people is pretty
immoral. I mean, if remembering things is crime, then thought crime is
illegal, yes? How would Kim Jong-un regulate your blockchain thoughts. Free
speech good. Censorship bad.

~~~
jasode
_> Evil and horror will always be just around the corner if you wish to see
it._

I think for the _average person_ who doesn't use Tor, they will not stumble
across child rape videos with a search for keywords _" child rape videos"_ in
Google or Bing.

However, if it's embedded in a global blockchain where the end user _must have
a copy of those illegal bytes_ for the blockchain to be verified & trusted,
does that mean every blockchain user is committing a crime by storing bytes of
child pornography? If someone wanted to sabotage a blockchain, it's hard to
think of a better way to deface it.

~~~
RichardHeart
You probably shouldn't be searching for that. To be free of all reminders that
crimes have been committed, think of all the people that would have to die.
Perhaps crimes should be punished more effectively instead of trying to get
meta-crime to do the work. For instance, money laundering is mostly used to
just add years to peoples normal crime sentences. You could just increase the
normal crime sentence. Imagine how violent the USA would be right now if
violent video games caused violence. The violent gaming industry has more
revenue than the movie industry. Metacrime enforcement takes money from real
crime enforcement.

~~~
jasode
_> You probably shouldn't be searching for that. _

That response doesn't engage with the difficult scenario I laid out. To
restate: If you want a law-abiding-wouldn't-hurt-a-fly citizen to participate
in the blockchain, _the citizen must copy the illegal child pornography_ to
his harddrive to satisfy the functionality of the blockchain. The citizen is
not "searching for it"; instead, the citizen _must have it_.

~~~
Artlav
For some extra twists, contemplate one-time-pad encryption.

You can claim that some random set of data on someone's machine is an
encrypted child porno video, and provide a "key" that would decrypt it.

Try explaining why that's not real to a clueless judge.

Anyway, i hope the legal system would recognize the difference between having
intent to store cp and not having such intent. Otherwise anyone can be made or
proven to have stored it.

~~~
Dylan16807
> Try explaining why that's not real to a clueless judge.

Judges aren't stupid. You can easily explain why the random data isn't
something. You can't explain your way out of unencrypted data being
objectively there.

> Anyway, i hope the legal system would recognize the difference between
> having intent to store cp and not having such intent.

If you know how blockchains work, then it is intentional.

> Otherwise anyone can be made or proven to have stored it.

Not for any real standard of proof.

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nickpsecurity
The author doesn't touch enough on just how much social damage can come from
this feature. Permanent ostracism, shunning, blackmail, lower pay, and so on.
People love judging and hating on other people when they can point fingers
while hiding their own malfeasance. Certain things will show up while others
won't in a model where we try to blockchain everything. The idea that they'll
evolve some form of forgiveness instead runs contrary to how human nature has
played out so far.

Now, one might argue the benefits outweigh the harm. That would be a different
discussion even though the article does list some of them. It gives a start on
it.

~~~
RichardHeart
Feedback systems are much better reward than risk. They prevent much more harm
than they cause. They are one of the best replacements for use of force to
encourage honorable action. Technology is almost always a net win.

------
cmurf
And then what of the right to be forgotten? What if an EU court orders forking
immediately prior to the negative material (fact or libel)? The order applies
only to blockchain hosts in the court's jurisdiction, but very quickly which
fork is canonical? One on the moon or in orbit? It seems like a consequence is
centralization, and at that point it's a sitting duck to use of force,
manipulation or destruction.

So how does a decentralized system avoid the (seemingly) inevitable
pressure/threat to centralize?

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jankotek
Every blockchain in existence was altered or forked at some point.

~~~
awgneo
Absolutely; blockchain technology is just the shift of power from one group to
another.

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runeks
Blockchains are forgotten just as easily as any other data if the last backup
is lost.

Proof-of-work, however, makes it expensive to modify history. But it doesn't
change the fact that, in order to prevent data loss, the only solution is
backups at multiple, independent locations.

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RichardHeart
What if you hide very small images of bad things inside high res photos, say,
in the reflections in eyes. What about in frames of movies? What if you use
Steganography to hide bad things in friendly, popular images, then publish the
key? What if you just spam an evil image to everyone's email? Hide it in
frames of a gif?

By this logic, we must all stop all communications, for communicating can be
evil. Good bye first amendment.

~~~
mirimir
Well, there are people in jail whose Freenet nodes handled child porn. I
suspect that some of them are innocent. But they couldn't afford to hire
expert witnesses, to counter bogus testimony about attribution in Freenet. So
they settled. So much for plausible deniability.

------
known
Decentralized + Private + Cloud + Immutable on top of AUDIT TRAIL

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Mendenhall
Thats what I really value about them.

It removes all of the below and then some.

"That never happened.

Forget I said that.

Can we start again?

I’m just going to pretend you didn’t just say that."

------
carapace
"This will go down on your permanent record."

