fjahr

Bitcoin Socratic Seminar in Frankfurt (27.08.2020)

Part of Bitcoin Week. For more information on Bitcoin Socratic Seminars in general, see https://bitdevs.org/ and https://bitdevs.berlin/.

Usually we talk about new topics of the last 4 weeks but since this group is not meeting regularly it will be more of a "best-of" of the last ~2 months. Also, feel free to bring your own topic if you feel something is missing (has to be in line with our general selection guidelines, no promotion of commercial services please). Ideally notify me before we start so I can make time for it or send me a message on twitter (@fjahr).

Security

• Malicious Tor relays changing Bitcoin addresses
• Ledger data breach

fjahr

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  setTimeout( () => {
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      Array.from(document.getElementsByClassName("ajax-pagination-btn")).forEach(l => l.click());
      f();
    } else {
      console.log("Done");
    }
  }, 1000); // May need to adjust this depending on your internet connection and machine performance
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fjahr

With --enable-debug

$ src/bitcoin-cli getblockchaininfo
{
  "chain": "main",
  "blocks": 220002,
  "headers": 613884,
  "bestblockhash": "00000000000000f8e6ea4282254b6cbc518a519ac7e1de83a8b7f413c16bc2c7",
  "difficulty": 3275464.586565617,

fjahr

This succeeds:

• 50 outputs of 1 BTC in the same destination
• Send 10.5 BTC
• 2 groups are used for the inputs, in total there are 20 inputs

    def test_destination_groupings(self):
        '''
        If a destination has more than 10 outputs, exactly 10 outputs should
        be used when spending from that destination
        '''

fjahr

Maintaining your fork

Syncing your fork

• https://help.github.com/en/articles/configuring-a-remote-for-a-fork
• https://help.github.com/en/articles/syncing-a-fork

old notes:

Git commands

fjahr

Lightning Network MW Message Types

List of all Lightning Network Message Types for easy & quick overview.

Messages with strikethrough style exist in the original RFCs but are currently removed in Lightning MW.

Setup & Control (0 - 31)

Messages related to connection setup, control, supported features, and error reporting.

• 16: init
• 17: error

fjahr

Lightning Network Message Types

List of all Lightning Network Message Types for easy & quick overview.

Setup & Control (0 - 31)

Messages related to connection setup, control, supported features, and error reporting.

• 16: init
• 17: error
• 18: ping
• 19: pong

fjahr

Research

• Specs: https://github.com/lightningnetwork/lightning-rfc
• Blogposts on Specs by Rusty Russel (somewhat outdated) https://medium.com/@rusty_lightning/the-bitcoin-lightning-spec-part-1-8-a7720fb1b4da
• Lightning dev mailing list https://lists.linuxfoundation.org/pipermail/lightning-dev/

Papers

• Original white paper (Poon & Dryja) https://lightning.network/lightning-network-paper.pdf
• Follow-up by Rusty Russel https://github.com/ElementsProject/lightning/blob/master/doc/deployable-lightning.pdf

Implementations (Big 3)

fjahr

defmodule MyApp.Plugs.Debug do
  @behaviour Plug

  require Logger

  def init(default), do: default

  def call(conn, _) do
    case conn.request_path do
      "/path/to/error" ->

fjahr

"""
Suppose you are given a list of possible Bitcoin that you control (inputs). You
need to pay someone exactly 0.71 BTC. How would you select exactly 2 inputs in
such a way as to minimize the change output if you could ignore fees? Write a
python function that selects the two inputs.
"""
from itertools import permutations

TEST_INPUTS = [0.21, 0.59, 1.34, 3.45, 0.3, 0.84, 0.53, 0.62, 0.70, 0.21, 0.44,
               0.28, 0.39, 200.9, 4.34]