5 ms·

How porn links and Ben Bernanke snuck into Bitcoin's code

50 points by T-A 14y ago

wyck 14y ago
There is dirty money and then there is dirty dirty money.
- camus 14y ago
  but how to tell the difference ? lol
  - ZeroCoin 14y ago
    Come on guys, this is HN. Not Reddit.
    - asveikau 14y ago
      Face it, all web communities eventually evolve into YouTube comments.
      - lucian1900 14y ago
        Although, especially recently, YouTube comments have gotten much better.
pyre 14y ago
When you attempt to make something that "no one can control," then things like this happen. Same thing with child porn on Tor .onion addresses. I'm curious what the implications of making some of these removable from the block chain though. Would it just end up being some central authority deciding which transactions are 'appropriate?' Is there a deterministic way of filtering out these 'data spam' transactions (without side-effects)?
- deleted 14y ago
  [deleted]
- ZeroCoin 14y ago
  re: "is there a deterministic way[?]" I would assume so. Perhaps adding a word-checker to bitcoin clients that looks for recognizable words (or attempts to validate a URL found inside the most recent block). If block contains words or URLs, disregard it. If not, accept it. Now Namecoin on the other hand...
  - tlrobinson 14y ago
    If I understand correctly, these people are using special software to encode data in transactions, namely the output addresses. You can only embed arbitrary data in blocks if you're able to mine a block (like Satoshi's headline in the genesis block and Dan Kaminsky's Ben Bernake ASCII art), otherwise you need to encode it in the transaction data.
    - ZeroCoin 14y ago
      Well then all of the worries about this child-porn being in the blockchain are warrantless. You could create a link to child-porn from this very comment I just posted using the right cipher. I am sure of it.
      - gizmo686 14y ago
        What if A) your comment was preserved as a part of the block-chain that could not be removed without doing serious damage to bitcoin. And B) the cipher you are using is a publicly known cipher recognized as the standard way of encoding data into the block-chain.
    - rlpb 14y ago
      Anyone sending Bitcoin can add arbitrary data in his transaction; no need to be a miner: https://en.bitcoin.it/wiki/Script#Transaction_with_a_message https://en.bitcoin.it/wiki/Script#Transaction_with_a_message
unimpressive 14y ago
Wait, HN is now a source of comments for CNN? That's worrying.
- gwern 14y ago
  I dunno, I think I'd trust random HNers for accuracy in their technical commentary more than I would CNN. (This is more criticism of CNN than praise of HN, understand.)
  - lostlogin 14y ago
    I don't know about that. With care there is a hell of a lot to be learnt here and at least the crap gets down voted, where news site promote popular stories. Link bait versus quality comments and voting.
- danso 14y ago
  Thanks to a HN thread I posted in, I had my very first mention in the New York Times Magazine http://www.nytimes.com/2013/03/24/magazine/the-3-10-13-issue.html?_r=0 http://www.nytimes.com/2013/03/24/magazine/the-3-10-13-issue...
deleted 14y ago
[deleted]
smrtinsert 14y ago
I was surprised when I didn't see this on HN first. I wonder what would happen if an organization like wikileaks began injecting documents into the blockchain.
- nwh 14y ago
  There's already a 7z binary of wikileaks crap in there. About 3MB of the stuff.
joshschreuder 14y ago
It would be interesting to see a tool that searched the blockchain extracting possible plaintext decodings.
DigitalSea 14y ago
The aspect that worries me about this is that links to child pornography websites concealed within transactions could make it theoretically possible for people to share child pornography in a somewhat anonymous way. Given the anonymous nature of the currency it appears it could be used to transmit highly illegal content within the transaction. Although having said that, the same could be said for the Tor network and onion addresses contributing to the same thing. That's the name of the anonymous game, people will do illegal and questionable things that's just the way it will always be. How would these injectable pieces of data be removed from transactions without exposing transactions to attacks?
- epscylonb 14y ago
  You can't put arbitrary data in a transaction, at least not very easily. The bitcoin devs are pretty clear that the bitcoin network and blockchain should not be used for messaging or store non transaction related data. What actually is happening here, is that miners have the opportunity to put a small amount of arbitrary data in a block when they mine. Ideally this is should be random data, its purpose is to change the data being hashed so you get a different hash each time you try. In my view the author of bitcoin set a bad precedent by including a newspaper headline referring to bank bailouts in the very first block. However I can't begrudge him for that too much. Since 2009, people have included prayers and accusations of illegal activity (trolling) in blocks. Assuming increased bitcoin adoption, I see mining getting more and more centralized, already I don't think any of the major mining pools would be silly enough to include CP or other illegal content. It would take many blocks to store a non trivial sized image in the blockchain, and if they put a link in instead then of course the host could be taken down.
  - rlpb 14y ago
    > You can't put arbitrary data in a transaction, at least not very easily. No; it's very easy. Anyone sending Bitcoin can add arbitrary data in his transaction; no need to be a miner: https://en.bitcoin.it/wiki/Script#Transaction_with_a_message https://en.bitcoin.it/wiki/Script#Transaction_with_a_message
  - 14y ago
bitcoinctf 14y ago
If you know a bit about web security (think Stripe CTF 2.0) and would like Bitcoins to try this, you can visit http://bitcoinctf.com http://bitcoinctf.com
rmc 14y ago
This could get very "interesting" if people started building a communication system on top of BitCoin. It could get bitcoin shut down....
junto 14y ago
If I understand this correctly, the blockchain transaction file is already pretty big (i.e. a couple of GBs). When you first setup Bitcoin on your machine you are basically required to download this file, and it is then kept up to date using Bittorrent, presumably with partial updates? I believe that there is a way (within the bitcoin design), such that the file size can be limited, firstly by only downloading the transaction headers, and / or secondly, by removing historical transactions (by breaking off branches from the Merkle tree [http://bitcoin.stackexchange.com/questions/10333/blockchain-long-run-issue] http://bitcoin.stackexchange.com/questions/10333/blockchain-...). However, when do those measures come into play? Do they have to be switched on? If so how, the whole thing is decentralized? Are the full transaction histories already being pruned?
- skriticos2 14y ago
  The header only download is a client side thing and can be done already (with a client that supports it). The Unused Output Tree (UOT) - the second thing you mentioned - needs amendment to the blockchain (adding checkpoints). https://en.bitcoin.it/wiki/Thin_Client_Security#Header-Only_Clients https://en.bitcoin.it/wiki/Thin_Client_Security#Header-Only_...
charlejshort 14y ago
Short sell bitcoin; then insert base-64 encoded child porn. (or perhaps salt multiple transaction and then leak decode process of higher res image) bling criminal mastermind or future jailhouse bitch...

50 points by T-A 14y ago

wyck 14y ago

There is dirty money and then there is dirty dirty money.

camus 14y ago
but how to tell the difference ? lol
- ZeroCoin 14y ago
  Come on guys, this is HN. Not Reddit.
  - asveikau 14y ago
    Face it, all web communities eventually evolve into YouTube comments.
    - lucian1900 14y ago
      Although, especially recently, YouTube comments have gotten much better.

pyre 14y ago

When you attempt to make something that "no one can control," then things like this happen. Same thing with child porn on Tor .onion addresses. I'm curious what the implications of making some of these removable from the block chain though. Would it just end up being some central authority deciding which transactions are 'appropriate?' Is there a deterministic way of filtering out these 'data spam' transactions (without side-effects)?

deleted 14y ago
[deleted]
ZeroCoin 14y ago
re: "is there a deterministic way[?]" I would assume so. Perhaps adding a word-checker to bitcoin clients that looks for recognizable words (or attempts to validate a URL found inside the most recent block). If block contains words or URLs, disregard it. If not, accept it. Now Namecoin on the other hand...
- tlrobinson 14y ago
  If I understand correctly, these people are using special software to encode data in transactions, namely the output addresses. You can only embed arbitrary data in blocks if you're able to mine a block (like Satoshi's headline in the genesis block and Dan Kaminsky's Ben Bernake ASCII art), otherwise you need to encode it in the transaction data.
  - ZeroCoin 14y ago
    Well then all of the worries about this child-porn being in the blockchain are warrantless. You could create a link to child-porn from this very comment I just posted using the right cipher. I am sure of it.
    - gizmo686 14y ago
      What if A) your comment was preserved as a part of the block-chain that could not be removed without doing serious damage to bitcoin. And B) the cipher you are using is a publicly known cipher recognized as the standard way of encoding data into the block-chain.
  - rlpb 14y ago
    Anyone sending Bitcoin can add arbitrary data in his transaction; no need to be a miner: https://en.bitcoin.it/wiki/Script#Transaction_with_a_message https://en.bitcoin.it/wiki/Script#Transaction_with_a_message

unimpressive 14y ago

Wait, HN is now a source of comments for CNN? That's worrying.

gwern 14y ago
I dunno, I think I'd trust random HNers for accuracy in their technical commentary more than I would CNN. (This is more criticism of CNN than praise of HN, understand.)
- lostlogin 14y ago
  I don't know about that. With care there is a hell of a lot to be learnt here and at least the crap gets down voted, where news site promote popular stories. Link bait versus quality comments and voting.
danso 14y ago
Thanks to a HN thread I posted in, I had my very first mention in the New York Times Magazine http://www.nytimes.com/2013/03/24/magazine/the-3-10-13-issue.html?_r=0 http://www.nytimes.com/2013/03/24/magazine/the-3-10-13-issue...

deleted 14y ago

[deleted]

smrtinsert 14y ago

I was surprised when I didn't see this on HN first. I wonder what would happen if an organization like wikileaks began injecting documents into the blockchain.

nwh 14y ago
There's already a 7z binary of wikileaks crap in there. About 3MB of the stuff.

joshschreuder 14y ago

It would be interesting to see a tool that searched the blockchain extracting possible plaintext decodings.

DigitalSea 14y ago

The aspect that worries me about this is that links to child pornography websites concealed within transactions could make it theoretically possible for people to share child pornography in a somewhat anonymous way. Given the anonymous nature of the currency it appears it could be used to transmit highly illegal content within the transaction. Although having said that, the same could be said for the Tor network and onion addresses contributing to the same thing. That's the name of the anonymous game, people will do illegal and questionable things that's just the way it will always be. How would these injectable pieces of data be removed from transactions without exposing transactions to attacks?

epscylonb 14y ago
You can't put arbitrary data in a transaction, at least not very easily. The bitcoin devs are pretty clear that the bitcoin network and blockchain should not be used for messaging or store non transaction related data. What actually is happening here, is that miners have the opportunity to put a small amount of arbitrary data in a block when they mine. Ideally this is should be random data, its purpose is to change the data being hashed so you get a different hash each time you try. In my view the author of bitcoin set a bad precedent by including a newspaper headline referring to bank bailouts in the very first block. However I can't begrudge him for that too much. Since 2009, people have included prayers and accusations of illegal activity (trolling) in blocks. Assuming increased bitcoin adoption, I see mining getting more and more centralized, already I don't think any of the major mining pools would be silly enough to include CP or other illegal content. It would take many blocks to store a non trivial sized image in the blockchain, and if they put a link in instead then of course the host could be taken down.
- rlpb 14y ago
  > You can't put arbitrary data in a transaction, at least not very easily. No; it's very easy. Anyone sending Bitcoin can add arbitrary data in his transaction; no need to be a miner: https://en.bitcoin.it/wiki/Script#Transaction_with_a_message https://en.bitcoin.it/wiki/Script#Transaction_with_a_message
- 14y ago

bitcoinctf 14y ago

If you know a bit about web security (think Stripe CTF 2.0) and would like Bitcoins to try this, you can visit http://bitcoinctf.com http://bitcoinctf.com

rmc 14y ago

This could get very "interesting" if people started building a communication system on top of BitCoin. It could get bitcoin shut down....

junto 14y ago

If I understand this correctly, the blockchain transaction file is already pretty big (i.e. a couple of GBs). When you first setup Bitcoin on your machine you are basically required to download this file, and it is then kept up to date using Bittorrent, presumably with partial updates? I believe that there is a way (within the bitcoin design), such that the file size can be limited, firstly by only downloading the transaction headers, and / or secondly, by removing historical transactions (by breaking off branches from the Merkle tree [http://bitcoin.stackexchange.com/questions/10333/blockchain-long-run-issue] http://bitcoin.stackexchange.com/questions/10333/blockchain-...). However, when do those measures come into play? Do they have to be switched on? If so how, the whole thing is decentralized? Are the full transaction histories already being pruned?

skriticos2 14y ago
The header only download is a client side thing and can be done already (with a client that supports it). The Unused Output Tree (UOT) - the second thing you mentioned - needs amendment to the blockchain (adding checkpoints). https://en.bitcoin.it/wiki/Thin_Client_Security#Header-Only_Clients https://en.bitcoin.it/wiki/Thin_Client_Security#Header-Only_...

charlejshort 14y ago

Short sell bitcoin; then insert base-64 encoded child porn. (or perhaps salt multiple transaction and then leak decode process of higher res image) bling criminal mastermind or future jailhouse bitch...