t4sk

# Simple wrappers for Material Design Lite text fields to use with SimpleForm (Rails)

SimpleForm.setup do |config|

  config.wrappers :mdl_field, tag: 'div', class: 'mdl-textfield mdl-js-textfield', error_class: 'is-invalid' do |b|
    b.use :html5
    b.use :input, class: 'mdl-textfield__input'
    b.use :label, class: 'mdl-textfield__label'
    b.use :error, wrap_with: { tag: :span, class: "mdl-textfield__error" }
  end

t4sk

How to create transaction using bitcoin-qt console

• Example of a transaction with single input and output

Start bitcoin-qt (on testnet)

bitcoin-qt -testnet

Open console

t4sk

How compute double sha256

This example is from BIP 143 - Native P2WPKH

Compute double sha256

> export PREV_OUTS=fff7f7881a8099afa6940d42d1e7f6362bec38171ea3edf433541db4e4ad969f00000000ef51e1b804cc89d182d279655c3aa89e815b1b309fe287d9b2b55d57b90ec68a01000000
> echo -n $PREV_OUTS | xxd -r -p | openssl dgst -sha256 -binary | openssl dgst -sha256
96b827c8483d4e9b96712b6713a7b68d6e8003a781feba36c31143470b4efd37

t4sk

How to import private key into bitcoin-qt

1. Convert private key to WIF

Click here to covert private key to WIF

In this example

• private key = 619c335025c7f4012e556c2a58b2506e30b8511b53ade95ea316fd8c3286feb9
• WIF = 92KuV1Mtf9jTttTrw1yawobsa9uCZGbfpambH8H1Y7KfdDxxc4d

t4sk

How to get bitcoins for development using Regtest

Start bitcoind

> bitcoind -regtest -daemon

Generate block chain

> bitcoin-cli -regtest generate 101

t4sk

Keybase proof

I hereby claim:

• I am t4sk on github.
• I am t4sk (https://keybase.io/t4sk) on keybase.
• I have a public key ASBBLtnHpb6we3Je4w_ctTBa7p2XJXl0fDn2Yb9-fi04ggo

To claim this, I am signing this object:

t4sk

pragma solidity ^0.5.3;

contract Wei {
    uint public oneEther = 1 ether;

    function test() public pure {
        assert(1 ether == 1e18 wei);
        assert(1 wei == 1);
    }
}

t4sk

How to activate segwit on regtest

Start bitcoind

> bitcoind -regtest -daemon

Generate block chain

> bitcoin-cli -regtest generate 432

t4sk

Keybase proof

I hereby claim:

• I am t4sk on github.
• I am tsknk (https://keybase.io/tsknk) on keybase.
• I have a public key ASDyZ1hblodO_TVvXYnHmPsWLpqRbYlgG6xzpy0Br_8m7Qo

To claim this, I am signing this object:

t4sk

const Web3 = require("web3");
const assert = require("assert");

const web3 = new Web3();

const email = "email@email.com";
const COLORS = [
    "red",
    "blue",
    "yellow",