qbig

# Javascript Node CircleCI 2.0 configuration file
#
# Check https://circleci.com/docs/2.0/language-javascript/ for more details
#
#
version: 2
jobs:
  build:
    docker:
      # specify the version you desire here

qbig

Go Concurrency Patterns

Generator: function that returns a channel

package main

import (
	"fmt"
	"math/rand"

qbig

// ECRECOVER implemented as a native contract.
type ecrecover struct{}

func (c *ecrecover) RequiredGas(input []byte) uint64 {
  return params.EcrecoverGas
}

func (c *ecrecover) Run(input []byte) ([]byte, error) {
  const ecRecoverInputLength = 128

qbig

EC.prototype.sign = function sign(msg, key, enc, options) {
  if (typeof enc === 'object') {
    options = enc;
    enc = null;
  }
  if (!options)
    options = {};

  key = this.keyFromPrivate(key, enc);
  msg = this._truncateToN(new BN(msg, 16));

qbig

// For eth_sign, we need to sign arbitrary data:
signMessage (withAccount, data) {
  const wallet = this._getWalletForAccount(withAccount)
  const message = ethUtil.stripHexPrefix(data)
  var privKey = wallet.getPrivateKey()
  var msgSig = ethUtil.ecsign(new Buffer(message, 'hex'), privKey)
  var rawMsgSig = ethUtil.bufferToHex(sigUtil.concatSig(msgSig.v, msgSig.r, msgSig.s))
  return Promise.resolve(rawMsgSig)
}

qbig

function getOriginAddress(bytes32 signedMessage, uint8 v, bytes32 r, bytes32 s) constant returns(address) {
  bytes memory prefix = "\x19Ethereum Signed Message:\n32";
  bytes32 prefixedHash = keccak256(prefix, signedMessage);
  return ecrecover(prefixedHash, v, r, s);
}

qbig

const message = web3.sha3('Hello World');
const signature = await web3.eth.sign(account, message);
const { v, r, s } = ethUtil.fromRpcSig(signature);

qbig

package main

import (
	"bytes"
	"compress/gzip"
	"fmt"
	"io"
	"log"
)

qbig

//
// The new assembly support in Solidity makes writing helpers easy.
// Many have complained how complex it is to use `ecrecover`, especially in conjunction
// with the `eth_sign` RPC call. Here is a helper, which makes that a matter of a single call.
//
// Sample input parameters:
// (with v=0)
// "0x47173285a8d7341e5e972fc677286384f802f8ef42a5ec5f03bbfa254cb01fad",
// "0xaca7da997ad177f040240cdccf6905b71ab16b74434388c3a72f34fd25d6439346b2bac274ff29b48b3ea6e2d04c1336eaceafda3c53ab483fc3ff12fac3ebf200",
// "0x0e5cb767cce09a7f3ca594df118aa519be5e2b5a"

qbig

package main

import (
	"fmt"
	"reflect"
)

type Foo struct {
	FirstName string `tag_name:"tag 1"`
	LastName  string `tag_name:"tag 2"`