Week 1

Building on bitcoin and setting up a dev environment

Prerequisites

We would like you to download some source code and attempt to compile it by following its build instructions before the course begins. This is to prevent any delays when starting on the day.

Please download the following repositories and try to follow and complete their build processes:

Software	Repository
NodeJS	https://nodejs.org/en/download/
TABconf wallet	https://github.com/KayBeSee/tabconf-workshop
Bitcoin Core	https://github.com/bitcoin/bitcoin
LND	https://github.com/lightningnetwork/lnd
Polar	https://lightningpolar.com/

Don't run bitcoind without specifying regtest (or signet) as the network in the configuration file (bitcoin.conf) or as a command line argument (see bitcoind --help). Otherwise you will start synchronising blocks for mainnet which is over 400 GB! At this point, you don't even need to run bitcoind just yet.

Goals

• Discuss and understand bitcoin philosophy

• Become comfortable and proficient in setting up bitcoin developer environments

• Be able to run and interface with Bitcoin Core and LND

  • Understand signet and regtest

  • Connect Bitcoin Core and LND programmatically

  • Interface with Bitcoin Core and LND using the CLI tools

  • Programmatic control of bitcoind and LND

  • Comfortable with running the full test suite(s) of Bitcoin Core

• Build a toy bitcoin wallet using a library

  • Add additional functionality of your choosing

• Develop a robust understanding of bitcoin topics both in theory and in practice:

  • Random number generation

  • Keys and key material

  • Derivation paths

  • Address types

  • Coin selection

• Gain experience with developing and using a Bitcoin wallet UI

Monday & Tuesday

1. Introduction to Qala

2. Programme structure

3. Icebreakers

4. Bitcoin Philosophy

5. Why we bitcoin

Wednesday

Resources

Name	Link
Lightning Book - Bitcoin Fundamentals review	https://lnbook.256k1.dev/#bitcoin_fundamentals_review
BIP0032	https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki
TABConf 2021 Building Your own bitcoin wallet with BitcoinJS	https://youtu.be/Bwz2P2hPVpk
Bitstein - Setting up a bitcoin lightning network test environment	https://medium.com/@bitstein/setting-up-a-bitcoin-lightning-network-test-environment-ab967167594a

Exercises

1. Read the Mastering Lightning book appendix on bitcoin transactions.

   • The username:password to access the book is: qala:lightning

2. Read about Hierarchical Deterministic Wallets in BIP0032.

   • You do not need to read/understand the child key derivation functions.

   • You should conclude with a strong understanding of how parent and child keys are derived from each other, and from a master seed .

3. Run through the TABconf wallet demo video found in the link above, following along with the demonstration.

4. Set up a manual bitcoin and lightning developer environment on regtest by following the guide from Bitstein: Setting up a Bitcoin/Lightning test environment

   • Note, this environment should ideally be built using Bitcoin Core and LND which have been build from source by yourself.

5. (Optional): If you finish all of the above, you can continue your progression by following the "TABConf wallet expansion" on Thursday

Deliverables

1. TABConf: please send us file: src/util/bitcoinjs-lib.ts.

2. Screenshot of your lightning developer environment resulting from the guide from Bitstein.

3. (Optional): Any extensions you made to the TABConf wallet.

Thursday

Exercises

1. TABConf wallet expansion. Add some or all of the following functionality to the wallet:

   1. one or more different receive address types, e.g. P2PK, P2PKH, P2SH, P2WPKH, P2WSH, P2TR, for the user to choose from

   2. Add a "watch-only wallet" mode

   3. Add full backup and restore functionality

   4. Improve UI/UX for a user who has many different sub-wallets derived from their seed

   5. Add ability to perform coin selection when sending payments

2. Bonus: Setup Bitcoin Core to use signet. Manually construct a transaction that could represent a 'uni-directional payment channel opening transaction' with an instructor, and produce (off-chain) update transactions for 3 purchases in hex format and send them to us.

Friday

Exercises

• Run Bitcoin Core, which has been built from source, in Signet mode

• Run all Bitcoin Core unit tests

• Choose area of the codebase you're interested in, pick a functional test that covers it, and then run that test

  • hint: see documentation in test/README.md for clues on how to run individual tests)

• Follow through the Bitcoin Core v23.0 Release Candidate Testing Guide, report any bugs or issue that you find to the Bitcoin Core GitHub issue tracker.

  • You might find answers to questions you have in the meeting logs for a bitcoin-core-pre-review (club) meeting held on the guide: meeting log.

• Send a regular P2WPKH tx to an instructor on signet.

• Run the Miner simulation exercise.

• Connect to the Bitcoin Network using tinybitcoinpeer.

  • Extend the functionality of tinybitcoinpeer to do something interesting!

• BONUS: Modify bitcoind User Agent string in the source code and recompile

• OPTION: Interact with a testnet instance of LightningK0ala/satoshis.place

Deliverables

1. Screenshot of Bitcoin Core running in signet mode (output of bitcoin-cli -signet -getinfo)

2. Screenshot of Bitcoin Core unit tests completing (they should all pass, let us know if they don't!)

3. Screenshot of you running a single functional test that you chose

4. Some brief feedback/notes on the Release Testing Guide

5. A P2WPKH transaction in hex format

6. A brief explanation on what the miner simulation is able to simulate