Topic: Illegal content in the blockchain - page 2. (Read 23587 times)

The protocol would need to be changed so a node can provide partial blocks. That's the point of the merkle tree structure, the pruning aspect was just never implemented.

In the case where an output both contains arbitrary data and is also spendable, you do indeed need to get >50% of the mining power to delete the transaction.

I think it'd be easy to make an analogy to a judge. If you publish a full page ad in the New York times containing some obfuscated or encrypted illegal material, that doesn't make the NYT, the printing company or people who bought the paper guilty of a crime. Now, the court of public opinion on the other hand ....

True, but it's not too difficult for the attacker to insert arbitrary data with OP_DROP and have Eligius or some other tolerant miner include it into a block. Then the arbitrary data is spendable and can't be forgotten.


I'm not so sure about this. Courts are used to being able to order service providers to remove illegal material, but with Bitcoin this is uniquely a technical impossibility. They might not understand. And it would be easy to get an emotional response out of average people: "Breaking news: Bitcoin banks refuse to delete child porn."

Doesn't changing the block result in invalidating Merkle root of that block, invalidating the block and the rest of block chain?

Or you meant that the miner may choose to skip the bogus transactions prior to mining the hash for given block? How? Setting a strict rules on his bitcoind? Still, some data may escape and become permanent.

OP is trying to overwhelm authorities so that the FBI will get off his ass.

Why is everyone so freaked out about this?

How is it any different than UPS or the post office delivering heroin and cocaine to people through silk road? It's not the deliverer who gets arrested. It's the guy who introduces the shit, or the guy who receives the shit. I've been runnin my client for a few months straight now, and I've never seen a hint of kiddy porn pop-up on my screen from the blockchain and I'm sure as hell not going to look for it. As far as I know, it's not even there rendering me safe from any legal allegations.

This has been discussed quite a few times before, which may be why not many developers have commented.

Theymos' entry is incomplete, so I extended it. There's another situation in which it's safe to delete transaction data: if you can prove it'll never be used. The transactions that embedded flags, ASCII Bernanke etc could be deleted without risk because the chances of finding a private key that hashes to a line of English text is extremely remote. What's more, transactions with non-random looking hashes or pubkeys can be automatically identified.

Data can also be included in tx input scripts. However data blocks there don't have any effect on anything, ie, with the right database structure you can record the original hash of the transaction, then delete the unneeded data blocks if they have no effect on the connected output script.

If you encrypt the data before putting it into the block chain, the bad transactions probably can't be reliably identified. However they also shouldn't pose any legal threats to the miners. If the key is publically revealed, the same as above applies - the outputs can be removed without risk.

In short, this "attack" is unlikely to be anything more than an inconvenience. Judges would certainly frown on attempts to game the legal system like this, it'd just be a waste of court time, and might be considered entrapment.

you know we could get bitcoin down to 2USD today, if we wanted too. xD

we could use this, and it would stay @ 2 for probably the duration of it's usage and existence.

You can have up to 520 bytes of contiguous data, and you can fill an entire block with data only slightly broken by opcodes. These transactions are accepted if they are received in a block -- they are just not relayed.

Theymos great entry. Thank you for providing so much useful info.

20 bytes, AFAIK (one address). You can embed larger blocks (up to 512?) using OP_NOP but I don't think those are accepted by the standard client at the moment.

See also the Len Sassaman ASCII art, it's width is 20:

http://pastebin.com/raw.php?i=BUB3dygQ

Added:
https://en.bitcoin.it/wiki/Weaknesses#Illegal_content_in_the_block_chain

I think it will be a problem in the future, though probably not too severe.

How large can a continuous custom block of content that can be embedded in to the blockchain be?

Nothing (read this thread, it might help)

It happened, so it is definitely possible.

Embedding some really WRONG political, religious, porn etc. content into the blockchain forever might be real problem, IMHO.

This it the kind of "news" all journalist believe to understand and will spread it heavily. Do we need another bad impact on Bitcoin in news?

For most people, if they are told "there is child porn inside Bitcoin blockchain", they will get negative attitude against it. They will not care if the blockchain is normally not viewable nor that that "porn" is funny ASCII art made of dots and stars. Actually, in Canada, they might arrest you immediately ;-) http://www.comicbookresources.com/?page=article&id=32958.

Hard drive heads float on an air cushion of laminar boundary flow above the spinning platter. While the drive is assembled in a meticulously clean environment (since the heads float closer to the disk surface than than the size of a smoke particle), there is a filtered vent hole so the drive can equalize pressure with the outside. This is why the drive listed above has a maximum operating altitude - with no air pressure, there is no air cushion, and the heads tear into the disk surface.

Since this isn't a hard drive thread, but rather an undying troll thread, I will point out that I can have a one-time pad that decrypts the block chain into kiddie porn. I suppose it would be up to you to decide if it is the block chain or the one-time pad that is the actual porn.

I was under impression it is possible to embed completely custom text into the blockchain:
https://en.bitcoin.it/wiki/Incidents#ASCII_embedding_into_blockchain

Is this possible or not?

If it is what prevents someone from embedding illegal content?

This is not a security weakness so should not be on that page.

I don't agree that it is a weakness.  Webster's English Dictionary could be illegal encrypted content, if you have the right algorithm.  Any string of bits can be re-structured to be something its not by running it through the right hashing algo.   In this case the hashing algorithm itself that turns Webster's Dictionary into something else would be the illegal content, not Webster's Dictionary.


also,

Has any of the developers commented on this issue? It sounds like this could potentially be a big problem that could criminalize every bitcoin user.

If I understand it correctly:
1. someone can store some illegal data into bitcoin (copyrighted content, child porn ...)
2. he lets everyone know what they are distributing/storing
3. if you continue to use bitcoin you can be charged for distributing/possessing illegal content

Could someone with more knowledge about this issue please add some info to:
https://en.bitcoin.it/wiki/Weaknesses

I don't recall criminal justice being one of my aims.