Creating op-return transactions

op-return.js

var util = require('util');

var bitcoin = require('bitcoinjs-lib');
var Chain = require('chain-node');

var chain = new Chain({blockChain: "testnet3"});

var b = new Buffer("Hello, world.");
var t = new bitcoin.Transaction();
t.addInput("ca7e12c753bd2a268e6f038509d72f3c44fd24064ed5ef8cde13ec987d495a64", 0);
t.addOutput("mr4CZmLR9pTv91jBgkDrvFnV29hZpr8yEn", 1000000);
t.addOutput(bitcoin.Script.fromChunks([bitcoin.opcodes.OP_RETURN, b]), 0);
t.sign(0, bitcoin.ECKey.fromWIF("KzRXiPFrTwPR7RRPfSSqLMvBFHAkncsUcehFTcZ1RMTUmjG9qE6P"));
console.log(t.toHex())

chain.sendTransaction(t.toHex(), function(err, resp) {
  console.log("error=" + util.inspect(err));
  console.log("response=" + util.inspect(resp, {depth: null}));
});

Here is the transaction created by this program:

http://explorer.chain.com/transactions/d0a12fb3f5fd2536decddfb6701077b6312bc3fe4c29df51a84f19eec01fe2fc#!transaction-op-return