#op_return

Pese a los datos on chain, la “guerra de clientes” en Bitcoin no cede

The Bitcoin community is split over Bitcoin Core developers’ decision to remove a limit on arbitrary data stored in transactions, a move that traces back to a debate first raised by Bitcoin creator Satoshi Nakamoto in 2010. Bitcoin Core v30’s expected release next month will remove the 80-byte cap on OP_RETURN, an opcode used for saving arbitrary data (any non-financial data) onchain. The…

A 'Proof of Proof' Startup Is Building Their Entire Blockchain with Bitcoin's 80 Bytes of Data as Foundation

Bitcoin enables 80 bytes of Arbitrary data to be included on its blockchain. VeriBlock, a new startup trying to develop the OP_RETURN command has now started a debate where it argues that this additional space can be used without being considered as spam. VeriBlock is a new company that is...

The Bitcoin protocol allows adding metadata to Bitcoin transactions. This is done by adding another output with an OP_RETURN operator. The OP_RETURN operator signals the Bitcoin nodes that this output is not vital for Bitcoin transactions and will never be spent, so that they aren’t obligated to store it.

The steps for putting a transaction containing meta data are as follows:

Get a Bitcoin address with a positive balance

Create an output Bitcoin address that will receive the transaction

Build the transaction

Broadcast the transaction to the Bitcoin network

How much data can you put on each transaction?

Every transaction can have up to one OP_RETURN output according to the Bitcoin protocol. Each OP_RETURN output can contain up to 80 bytes of data, which is equivalent to 80 ASCII characters or 160 hexadecimal symbols.

Step 1 - Get a bitcoin address with a positive balance

If you already have a bitcoin address with a positive balance, your can skip to Step 2. If not, you can first create a new key:

var inputKey = bitcoin.ECKey.makeRandom(); //print your private key (in WIF format) console.log(key.toWIF()); //print your key's public address console.log(key.pub.getAddress().toString());

You can now go ahead and send some satoshis to this address from your Bitcoin wallet. You can use a Bitcoin adress QR code generator to simplify the process.

Step 2- Create an output address

You can repeat the steps from above to create another key that will server as the ouput of our transaction

Step 3 - Building the transaction

var bitcoin = require ('bitcoinjs-lib'); var tx = new bitcoin.TransactionBuilder(); var transactionId, //a transaction that has the unspent output unspentOutputId, //the serial id of the unspent output in the transaction inputKey, //the key that corresponds to the unspent output address outputKey,//the key that corresponds to the recipient of the transaction amount; //the amount to be transferred - should be the entire unspent output minus a reasonable fee //Creating the OP_RETURN script var data = new Buffer(”Your message here”); var dataScript = bitcoin.scripts.nullDataOutput(data); //Building the transaction tx.addInput(transaction_id, unused_output); tx.addOutput(dataScript, nspentOutputId); tx.addOutput(outputKey.pub.getAddress().toString(), amount); tx.sign(0, inputKey); //Printing the signed transaction console.log(tx.build().toHex());

Step 4 -Broadcasting the transaction

There are many ways to broadcast your transaction. For example, you could use your own bitcoind using the JSON-RPC API. But easiest, is to use an online service to post the transactions. We'll demonstrate how to use chain.com.

First, you'll need to sign up on chain.com and generate your API token. Then, you need to install the chain.com package from npm.

npm install -S chain-node

Then, in your code you can broadcast the transaction as follows:

Chain = require('chain-node'); chain = new Chain({ keyId: 'your_key', keySecret: 'your_secret', blockChain: 'bitcoin'}); chain.sendTransaction(tx.build().toHex(), function(err, res){ //do something with the repsonse });

The Bitcoin protocol allows adding metadata to Bitcoin transactions. This id done by adding another output with an OP_RETURN operator. The OP_RETURN operator signals the Bitcoin nodes that this output is not vital for Bitcoin transactions and will never be spent, so that they don’t need to store it.

The steps for putting a transaction containing meta data are as follows:

Get a Bitcoin address with a positive balance

Create an output Bitcoin address that will receive the transaction

Build the transaction

Transmit the transaction to the Bitcoin network

How much data can you put on each transaction?

Every transaction can have up to one OP_RETURN output according to the Bitcoin protocol. Each OP_RETURN output can contain up to 80 bytes of data, which is equivalent to 80 ASCII characters or 160 hexadecimal symbols.

Step 3 - Building the transaction

var bitcoin = require ('bitcoinjs-lib');

var tx = new bitcoin.TransactionBuilder();

var transactionId, //a transaction that has the unspent output

unspentOutputId, //the serial id of the unspent output in the transaction

inputKey, //the key that corresponds to the unspent output address

outputKey,//the key that corresponds to the recipient of the transaction

amount; //the amount to be transferred - should be the entire unspent output minus a reasonable fee

//Creating the OP_RETURN script

var data = new Buffer(”Your message here”); var dataScript = bitcoin.scripts.nullDataOutput(data);

Die Blockchain-Lizenz für digitale Kunstwerke

Kunst ist eines dieser Dinge, die den Sprung ins digitale Zeitalter nicht wirklich geschafft haben. Ein Künstler und eine Anwaltskanzlei haben nun eine Lizenz entwickelt, welche helfen soll, einen Markt für digitale Kunstwerke entstehen zu lassen. (more…)

Counterparty issued an open letter to bitcoin's core developers last week asking to reconsider OP_RETURN component, which allows people to store extra data in blockchain. OP_Return was revised to store 40 bytes from 80 bytes

"This upset CounterParty, because as a financial trading platform that allows people to create new asset classes and financial derivatives to be traded on the bitcoin block chain, it says that it needed those 80 bytes to store its data."

Limit makes OP_RETURN unusuable for Counterparty's purposes.

This forces Counterparty to use multisig outputs to accomplish goal (using more than one signature per output) which is a much more awkward construction to accomplish goal.

Bitcoin core developer Jeff Garzik argues they shouldn't (in Bitcoin Talk forum: http://goo.gl/m5QGJc) because using full nodes for data storage is abusing an all volunteer network resource, 90% of which is dedicated to the currency. He argues Counterparty and Mastercoin started using bitcoin P2P nodes as data stores and "didn't engage community before doing it either".

PhantomPhreak, core developer at Counterparty says bitcoin core developers job should be to make it possible for others to build on the blockchain, arguing both parties get something out of relationship:

1) "By piggybacking on the bitcoin block chain, Counterparty and other new services get pre-baked services including trusted timestamping, proof of publication,peer discovery and anti-DOS measures."

2) "Bitcoin, in turn, gets to stay relevant, (s)he argues: “Bitcoin can be very conservative with the kinds of functionality that it directly supports, while still rapidly acquiring the new features that it needs to stay relevant and useful.”

Counterparty has not contributed to bitcoin core's open source effort, which bitcoin's core developers say they need help pitching in.

PhantomPhreak says a few of the bitcoin developers are trying to prevent counterparty from using the protocol with this new release.

Core developer Mike Hearn has an idea which he first suggested in 2012 that would store in the blockchain a pointer to a third party which would host data instead of the blockchain hosting data.

Another issued has come up, regarding the reduction of transaction fees. 

Peter Todd, who contributes to btc code, said he's worries that this could open up network to spam and denial of service attacks. 

Gavin Andresen says that attackers have little incentive to launch DoS attacks.

Vitalik Buterin suggests that 'smart fees' could sovle this problem by allowing people to pay for what they wanted to store. He says that its the protocols fault that OP_Return is an issue and in an ideal world fees would be mandatory. He says if you can pay the fees, you should be able to do whatever you want.