6 ms·

Hidden surprises in the Bitcoin blockchain and how they are stored (2014)

88 points by astdb 9y ago

deleted 9y ago
[deleted]
comex 9y ago
(2014). Wonder how much other stuff has been added since then.
- amingilani 9y ago
  Well, if you check out tx `26c5ca404cc37abf77fc722a11f56b34a481f7879b1c11fe68fcdcdf2a15626f`[1] it contains the following hex data in the OP_RETURN: 40616d696e67696c616e69203c332040697a7a617368616869642023536179497457697468426974636f696e2023466c6f6f64546865426c6f636b636861696e Which when converted to a string says: @amingilani <3 @izzashahid #SayItWithBitcoin #FloodTheBlockchain Clearly I love my wife (fiance actually but give it few months) [1]: https://blockchain.info/tx/26c5ca404cc37abf77fc722a11f56b34a481f7879b1c11fe68fcdcdf2a15626f?show_adv=true https://blockchain.info/tx/26c5ca404cc37abf77fc722a11f56b34a...
RustyRussell 9y ago
BTW, please don't use this address-spamming technique! You can simply put data after an OP_RETURN, which, while permanently encoding it in the blockchain, ensures that nodes know it can't be spent.
- 1ba9115454 9y ago
  That's fixed to 80bytes, perhaps space for a few smileys.
  - Normal_gaussian 9y ago
    Twit-chain
  - RustyRussell 9y ago
    But the encode-in-address method is limited to 20 bytes.
- anc84 9y ago
  A technical "solution" to money transfer that relies on saying pretty-please to avoid problems? Sounds like something I should invest in.
  - RustyRussell 9y ago
    Well, it's cheaper to use OP_RETURN, too.
russellsprouts 9y ago
> Along with the standard data, the original transaction also contains the message: 'The Times 03/Jan/2009 Chancellor on brink of second bailout for banks'[3]. Presumably this is a political commentary on Bitcoin compared to the insolvency of "real" banks. While it may be political commentary, including a headline from a widely known newspaper also proves that the block was created sometime after that date.
- ATsch 9y ago
  Yes, afaik this was the purpose... to prove the creator had not pre-mined a bunch of coins and was then going to cash then in later. Which is incredible foresight, because that's what ended up happening with some altcoins.
  - flashmob 9y ago
    There wasn't any competition to mine it for a long time, so post-mining would have been just as effective as pre-mining. We know that Satoshi ended up mining a lot of Bitcoin. Of course, all well deserved. Further reading on this topic: http://organofcorti.blogspot.com/2014/08/167-satoshis-hashrate.html?m=1 http://organofcorti.blogspot.com/2014/08/167-satoshis-hashra...
1ba9115454 9y ago
These days getting a 4kb image into the blockchain would cost you around 44 USD. i.e. 4096 x 200 satoshi fee = 819200 satoshis about .00819200 BTC. Add approximately a 50% overhead in the way you would need to store that image and you're looking at about .016 BTC.
- glebedel 9y ago
  transactions have been going through for a several weeks with 1-20 satoshi per byte. Unless you're in a hurry to get that image in a block, you can do it for 10 to 200 times cheaper than quoted price.
Twisell 9y ago
Doesn't that mean that a whole blockchain could possibly be deemed illegal in some country due to copyright infringement or other liability of publications laws? I mean if you can't erase the data and keep publishing it, some would say you are liable. I see that as a particularly twisted legal argument, but couldn't some country use that against blockchain infrastructure if they feel like it?
- zmonx 9y ago
  Yes, this is indeed one possible attack vector! For more information, please see: https://en.bitcoin.it/wiki/Weaknesses#Illegal_content_in_the_block_chain https://en.bitcoin.it/wiki/Weaknesses#Illegal_content_in_the... To quote: It is illegal in some countries to possess/distribute certain kinds of data. Since arbitrary data can be included in Bitcoin transactions, and full Bitcoin nodes must normally have a copy of all unspent transactions, this could cause legal problems. However, Local node policy generally doesn't permit arbitrary data (transactions attempting to embed data re non-standard), but steganographic embedding can still be used though this generally limits storage to small amounts. Various ideas have been proposed to further limit datastorage in the UTXO set but are not currently being seriously considered for deployment.
  - dogeyip 9y ago
    All the content on http://dogeyip.com/ http://dogeyip.com/ is pulled from data encoded into UTXO on the dogecoin blockchain. If you're clever you can encode as much data as you want into any block chain using this technique. Obviously, the techniques used here can also be used on the bitcoin blockchain. Example: All the text for the blog posts here are pulled via api from data encoded into UTXOs in the dogecoin blockchain: http://dogeyip.com/blog.html http://dogeyip.com/blog.html
- FrozenVoid 9y ago
  Interesting twist if bitcoin blockchain would be found to distribute illegal porn or private/secret/classified data(it already stores some wikileaks content). # How does government stop/censor a global p2p network? I guess they would put pressure on developers and bitcoin foundation to remove the offending data and update the (official) software to block/reject/deny any upload of it. I assume it would have to employ heavy filtering to prevent rogue actors from spamming illegal content and some functionality to revoke bad blocks(will probably require major changes in ledger code). If there is no change in client software it becomes exponentially harder to censor the data if not impossible: at some point this could be used as legal reason vs anyone hosting the full blockchain. The blockchain would have to be hard-forked to point to the censored version. (I have no idea how this suppose to work since each block depends on previous one: any incident will require to create a new blockchain fork from the start of offending block and this probably won't scale to dedicated attackers inserting illegal content into every block).
amingilani 9y ago
I once used the OP_RETURN to do the nerd equivalent of carving a heart in a tree. Tx `26c5ca404cc37abf77fc722a11f56b34a481f7879b1c11fe68fcdcdf2a15626f`[1] it contains the following hex data in the OP_RETURN: 40616d696e67696c616e69203c332040697a7a617368616869642023536179497457697468426974636f696e2023466c6f6f64546865426c6f636b636861696e Which when converted to a string says: @amingilani <3 @izzashahid #SayItWithBitcoin #FloodTheBlockchain
Tutankamon 9y ago
A map to find treasure or secret passwords or the end of the world plans...Just imagine what could end up in the blockchain. Part time capsule part safe part invisible ink part James bond part infinity. Just think of all the craziness..I need to put something in the blockchain. But what...
- tragomaskhalos 9y ago
  With terrible Dan Brown book and Tom Hanks film to follow ....
- cassetti 9y ago
  https://proofofexistence.com/ https://proofofexistence.com/
  - amingilani 9y ago
    Or my favorite: stamp.io If you have an Estonian ID, Stamp.io lets you sign it too! Full disclosure: I know the Stamp.io team, and they're awesome.
Stradivarius 9y ago
I don't quite understand - I get how images can be sent with a transactions but how do you see the image?
AgentSpoofer 9y ago
Eventually someone is going to make a program to store and retrieve child porn directly in the blockchain. That way it can be passed around and stored on hard disks but with thin deniability of "oh no, I just needed the blockchain so I could spend my buttcoins"

88 points by astdb 9y ago

deleted 9y ago

[deleted]

comex 9y ago

(2014). Wonder how much other stuff has been added since then.

amingilani 9y ago
Well, if you check out tx `26c5ca404cc37abf77fc722a11f56b34a481f7879b1c11fe68fcdcdf2a15626f`[1] it contains the following hex data in the OP_RETURN: 40616d696e67696c616e69203c332040697a7a617368616869642023536179497457697468426974636f696e2023466c6f6f64546865426c6f636b636861696e Which when converted to a string says: @amingilani <3 @izzashahid #SayItWithBitcoin #FloodTheBlockchain Clearly I love my wife (fiance actually but give it few months) [1]: https://blockchain.info/tx/26c5ca404cc37abf77fc722a11f56b34a481f7879b1c11fe68fcdcdf2a15626f?show_adv=true https://blockchain.info/tx/26c5ca404cc37abf77fc722a11f56b34a...

RustyRussell 9y ago

BTW, please don't use this address-spamming technique! You can simply put data after an OP_RETURN, which, while permanently encoding it in the blockchain, ensures that nodes know it can't be spent.

1ba9115454 9y ago
That's fixed to 80bytes, perhaps space for a few smileys.
- Normal_gaussian 9y ago
  Twit-chain
- RustyRussell 9y ago
  But the encode-in-address method is limited to 20 bytes.
anc84 9y ago
A technical "solution" to money transfer that relies on saying pretty-please to avoid problems? Sounds like something I should invest in.
- RustyRussell 9y ago
  Well, it's cheaper to use OP_RETURN, too.

russellsprouts 9y ago

> Along with the standard data, the original transaction also contains the message: 'The Times 03/Jan/2009 Chancellor on brink of second bailout for banks'[3]. Presumably this is a political commentary on Bitcoin compared to the insolvency of "real" banks. While it may be political commentary, including a headline from a widely known newspaper also proves that the block was created sometime after that date.

ATsch 9y ago
Yes, afaik this was the purpose... to prove the creator had not pre-mined a bunch of coins and was then going to cash then in later. Which is incredible foresight, because that's what ended up happening with some altcoins.
- flashmob 9y ago
  There wasn't any competition to mine it for a long time, so post-mining would have been just as effective as pre-mining. We know that Satoshi ended up mining a lot of Bitcoin. Of course, all well deserved. Further reading on this topic: http://organofcorti.blogspot.com/2014/08/167-satoshis-hashrate.html?m=1 http://organofcorti.blogspot.com/2014/08/167-satoshis-hashra...

1ba9115454 9y ago

These days getting a 4kb image into the blockchain would cost you around 44 USD. i.e. 4096 x 200 satoshi fee = 819200 satoshis about .00819200 BTC. Add approximately a 50% overhead in the way you would need to store that image and you're looking at about .016 BTC.

glebedel 9y ago
transactions have been going through for a several weeks with 1-20 satoshi per byte. Unless you're in a hurry to get that image in a block, you can do it for 10 to 200 times cheaper than quoted price.

Twisell 9y ago

Doesn't that mean that a whole blockchain could possibly be deemed illegal in some country due to copyright infringement or other liability of publications laws? I mean if you can't erase the data and keep publishing it, some would say you are liable. I see that as a particularly twisted legal argument, but couldn't some country use that against blockchain infrastructure if they feel like it?

zmonx 9y ago
Yes, this is indeed one possible attack vector! For more information, please see: https://en.bitcoin.it/wiki/Weaknesses#Illegal_content_in_the_block_chain https://en.bitcoin.it/wiki/Weaknesses#Illegal_content_in_the... To quote: It is illegal in some countries to possess/distribute certain kinds of data. Since arbitrary data can be included in Bitcoin transactions, and full Bitcoin nodes must normally have a copy of all unspent transactions, this could cause legal problems. However, Local node policy generally doesn't permit arbitrary data (transactions attempting to embed data re non-standard), but steganographic embedding can still be used though this generally limits storage to small amounts. Various ideas have been proposed to further limit datastorage in the UTXO set but are not currently being seriously considered for deployment.
- dogeyip 9y ago
  All the content on http://dogeyip.com/ http://dogeyip.com/ is pulled from data encoded into UTXO on the dogecoin blockchain. If you're clever you can encode as much data as you want into any block chain using this technique. Obviously, the techniques used here can also be used on the bitcoin blockchain. Example: All the text for the blog posts here are pulled via api from data encoded into UTXOs in the dogecoin blockchain: http://dogeyip.com/blog.html http://dogeyip.com/blog.html
FrozenVoid 9y ago
Interesting twist if bitcoin blockchain would be found to distribute illegal porn or private/secret/classified data(it already stores some wikileaks content). # How does government stop/censor a global p2p network? I guess they would put pressure on developers and bitcoin foundation to remove the offending data and update the (official) software to block/reject/deny any upload of it. I assume it would have to employ heavy filtering to prevent rogue actors from spamming illegal content and some functionality to revoke bad blocks(will probably require major changes in ledger code). If there is no change in client software it becomes exponentially harder to censor the data if not impossible: at some point this could be used as legal reason vs anyone hosting the full blockchain. The blockchain would have to be hard-forked to point to the censored version. (I have no idea how this suppose to work since each block depends on previous one: any incident will require to create a new blockchain fork from the start of offending block and this probably won't scale to dedicated attackers inserting illegal content into every block).

amingilani 9y ago

I once used the OP_RETURN to do the nerd equivalent of carving a heart in a tree. Tx `26c5ca404cc37abf77fc722a11f56b34a481f7879b1c11fe68fcdcdf2a15626f`[1] it contains the following hex data in the OP_RETURN: 40616d696e67696c616e69203c332040697a7a617368616869642023536179497457697468426974636f696e2023466c6f6f64546865426c6f636b636861696e Which when converted to a string says: @amingilani <3 @izzashahid #SayItWithBitcoin #FloodTheBlockchain

Tutankamon 9y ago

A map to find treasure or secret passwords or the end of the world plans...Just imagine what could end up in the blockchain. Part time capsule part safe part invisible ink part James bond part infinity. Just think of all the craziness..I need to put something in the blockchain. But what...

tragomaskhalos 9y ago
With terrible Dan Brown book and Tom Hanks film to follow ....
cassetti 9y ago
https://proofofexistence.com/ https://proofofexistence.com/
- amingilani 9y ago
  Or my favorite: stamp.io If you have an Estonian ID, Stamp.io lets you sign it too! Full disclosure: I know the Stamp.io team, and they're awesome.

Stradivarius 9y ago

I don't quite understand - I get how images can be sent with a transactions but how do you see the image?

AgentSpoofer 9y ago

Eventually someone is going to make a program to store and retrieve child porn directly in the blockchain. That way it can be passed around and stored on hard disks but with thin deniability of "oh no, I just needed the blockchain so I could spend my buttcoins"