Bitcoin?

Written by Greg Walker

What is bitcoin?

Bitcoin is an electronic payment system, but really it’s just a computer program.

When you run the program, it connects to other computers running the same program all over the world. This creates a massive network of computers that can communicate and share information with each other. All of this happens for one reason… to share a file, and this file is called the blockchain.

The blockchain is a file that contains transactions. Anyone can make a transaction and insert it in to a computer on the network. From here, it will be passed from computer to computer until everyone has a copy. Eventually, this transaction makes it in to the blockchain.

However, there’s a problem.

You can actually insert two conflicting transactions in to the network at the same time. For example, you can buy a pizza in one transaction, then create another transaction and use the same bitcoin to buy some beer. If you insert both of these transactions in to different ends of the network at the same time, some computers will get the pizza transaction first, and some computers will get the beer transaction first.

Who should get the bitcoin?

Both of these transactions can’t be written to the file, as that would be a “double-spend”. Still, we have a network of computers with conflicting transactions on them, and no single computer is in charge. So how can we decide?

Bitcoin solves this problem through a system called “mining”. Instead of writing all new transactions on to the blockchain (and writing double-spends on to the file), all new transactions get held in a waiting area called the “memory pool”. From here, each computer can collect the transactions from their memory pool in to a “block”, and try to add this block of transactions on to the blockchain. Whoever adds their block on to the blockchain first decides which transaction makes it.

So this is where the competition starts…

Each computer starts by putting their block (every block is different) through what’s called a “hash function”. This hash function takes in a block, and scrambles it to produce a random number from it. Unusual, I know, but this is what hash functions do. Interestingly, nobody knows what number a hash function will spit out based on the data you feed in to it – you just have to try it and find out.

Anyway, the contest here is to try and get a number from this hash function (or to be precise, a “block hash”) that is below a certain threshold number. If you can manage to get a low enough number from your block, you can add it on to the blockchain.

And that’s the competition.

For example, let’s say I have the beer transaction in my memory pool. I will construct a block, put that beer transaction inside it, then put that block through the hash function. If the number that comes out isn’t below the threshold, my attempt has failed. However, I can always make a tiny adjustment to the data inside the block (e.g. add a bit of extra data to the end of the block), and put it through the hash function again.

So “mining” basically involves hashing my block as fast as I can, trying to be the first to get a result below the threshold. If I get lucky, I will be the first computer on the network to do so. If this happens, I can send this block to all the other computers on the network, and they will add it on to their blockchain. Then, because this block contains the beer transaction, the conflicting pizza transaction gets kicked out of memory.

So by pure luck and randomness, the beer transaction is the one that makes it in to the blockchain.

The beer transaction may have entered the network slightly after the pizza transaction, but it doesn’t matter. It just so happened that a computer with the beer transaction in its memory was able to build a block and get a low enough hash for it before anyone else, so all nodes accept this block and add it to their file. Any conflicting transactions that are in memory get thrown away.

Upon receiving this new successful block, nodes will drop the current block they were working on and go back in to their memory pool to create a new one. This means that the blockchain is constantly being built, with new blocks of transactions being added on to the chain roughly every 10 minutes.

As a result, we have a system where anyone can insert transactions in to a network of computers, and these computers will all work hard to try and add them on to a shared file.

Thanks to this system of “mining” (preventing any double-spends from being written to the file), we have created an electronic payment system that runs over a network of computers, and it all runs without a cental point of control.

That’s Bitcoin.

Getting Started:
Download Bitcoin Core to get started for free today.

Hardware

These hardware projects explicitly state that they support bitcoin only.

Node: Buy (Plug and Play)

Project Description
MyNode Full Stack - Low Cost
Nodl Full Stack - Feature Rich
Nodl Samourai Full Stack - RAID backups
Raspiblitz Full Stack [EU) | USA]

Node: DIY

Project Description
Bitcoin Core - Guide Install Core on your computer
MyNode - Guide Full Stack (Rock64 / Pi3 / Pi4)
Samourai DOJO Full Node with API (PC / Pi4)
Raspibolt / Raspiblitz Lightning Node (Pi3 / Pi4)
RoninDojo Full Stack (Rockpro 64 / Pi4 / Odroid N2)
Thundroid Lightning Node (Odroid HC2)
Node Launcher UI to install Full Stack on PC
Other DIY Bitcoin Hardware Other DIY Hardware Projects

Other Hardware

Project Description
Bitpiggys Piggybank + Opendime
Coldbit Bitcoin Mnemonic Seed Backup
ColdCard Cold Storage Hardware Wallet
Opendime * Bitcoin Bearer Bond
Revealer Optical Seed Encryption Tool

* Currently only Bitcoin versions exist. NVK says this will probably always be the case.


Getting Started:
PC: Download Bitcoin Core
Android: Download Samourai Wallet
iOS: Download Blockstream Green (Use Google Authentication not Email/Phone)

Wallets

These wallets have explicitly stated that they support bitcoin only .

It is very important that you learn how to backup your mnemonic seed & that if you use a passphrase you back that up too. Read this document to learn more about backing up your wallet and check out the privacy page. See this report for a comparison of the features of many of the wallets listed below.

On-Chain

Project Description Platform
ABCore Bitcoin Core Full Node for Android Android
Armory Cold Storage & Multisig Desktop
Bitcoin Core Full node & Bitcoin wallet. Desktop
Blockstream Green Easy to use wallet. Use Google Authentication not Email/Phone. iOS & Android
Caravan Stateless Multisig Coordinator. Desktop
Casa Keymaster Multisig Bitcoin [see Google Drive note below] iOS & Android
Electrum The most feature rich bitcoin desktop wallet available today. Desktop & Android
Fully Noded Bitcoin Core GUI for iOS device iOS
GreenAddress Desktop companion to Blockstream Green mobile wallet. Deskop
Hodl Wallet Relatively new wallet with simple UI. iOS & Android
Lily Wallet Relatively new multisig wallet with simple UI Desktop
Specter Relatively new desktop GUI for Bitcoin Core optimised to work with hardware wallets Desktop
Muun Wallet Relatively new wallet with novel multi-sig 2-of-2 spending. Android
Samourai Wallet The most feature rich and advanced bitcoin wallet available on Android today. Android
Wasabi Wallet Privacy focused Bitcoin wallet, that implements trustless coin shuffling Desktop

Lightning

Project Description Platform
BLW A standalone SPV Bitcoin node with a fully functional built-in Lightning node. Android
Breez Mobile Non-Custodial Wallet [see Google Drive note below] iOS & Android (Beta)
Eclair Lightning Node Software Desktop
Eclair Mobile Lightning-ready Bitcoin wallet Android
Sparrow Wallet Relatively new desktop wallet with better UI/UX Desktop
RTL An easy to use interface for LND Desktop
Sats App Mobile Non-Custodial Wallet connected to Casa Node iOS & Android (Beta)
Zap Desktop Lightning Wallet. Mobile LND Interface Desktop, iOS & Android
Zeus Mobile app for LND users iOS & Android

[Note: Google Drive] : Google Drive backups on Breeze & Casa Keymaster allows those companies to access your email address, name and google profile picture. Strongly recommend using a separate google account to use these apps.

Custodial

Project Description Platform
Blue Wallet Bitcoin & Lightning wallet [1] iOS & Android
Bottle.li Lightning Social Tipping [5] Web
Opennode Accept Bitcoin & Lightning payments [4] Web
Tippin.me Lightning Social Tipping [3] Web
Wallet of Satoshi Lightning only wallet [2] iOS & Android

[1] : Blue Wallet's Lightning is Custodial by Default but users can opt to connect their app to their own Lightning Node using LNDhub. The On-Chain functionality is non-custodial.

[2] : Wallet of Satoshi is fully custodial meaning you do not have your private keys, thus you are not guaranteed full control of your funds.

[3] : Tippin.me is fully custodial meaning you do not have your private keys, thus you are not guaranteed full control of your funds.

[4] : Opennode is fully custodial meaning you do not have your private keys, thus you are not guaranteed full control of your funds. You can (and should) set reoccurring withdrawals to send any bitcoin you receive to your own wallet.

[5] : Bottle.li is fully custodial meaning you do not have your private keys, thus you are not guaranteed full control of your funds


Advanced Users

Getting Started:
Read 'Programming Bitcoin' by Jimmy Song (Hardcopy | GitHub).

Dev Tools

Backend Tools

Project Description
Bitcoin Forge Toolkit for tinkering with scripts, TXs and addresses.
Bitcoin Optec Dashboard Detailed Live Bitcoin Stats
bitcoin-s Scala Bitcoin Library
Bitcoin Playground Explore Raw tx Data
bitcoin-s Scala Bitcoin Library
Braiins OS Opensource Mining Software
CoinBin Web Wallet to learn
CypherNode API Server
Dojo End-to-end Bitcoin Wallet backing server
LibreTX Create Bitcoin tx's to learn
LNdash Simple web dashboard for LND
LNtop Lightning Network channel management
Mule Tools Bitcoin transaction broadcasting
Node Launcher Easy Launch Core & LND
Python Bitcoinlib Python Bitcoin Library
WebLN Interract with LN node via browser

LEARNING resources

Project Description
Bitcoin Dev Network Tutorials for aspiring Bitcoin Dev's
Bitcoin Reader Learn about Bitcoin Script (GitHub)
BitcoinJS & Core CLI Extensive guide to Bitcoin Javascript
Command Line Bitcoin Learning Bitcoin From The Command Line
Lightning Hood Information / Resources
Mastering Bitcoin How Bitcoin works - high level (Hardcopy | GitHub)
Programming Bitcoin How Bitcoin works - technical level (Hardcopy | GitHub)
Programming the Blockchain in C# Guide to Bitcoin in C#
Script Explorer Learn about Bitcoin Script (GitHub)

Services

Project Description
8333.io Trustless Bitcoin Service Provider
Blockstream Satellite Blockchain satellite service

Meetups

bitcoin only meetups website: bitcoinmeetup.info

Getting Started:
Watch the following videos:
1) The Bitcoin Standard - Saifedean Ammous on hard money
2) Why Bitcoin Matters - Aleks Svetski on the future of money
3) Bitcoin Genesis - Max Keiser on the origins of bitcoin
Then work through the step by step Bitcoin software tutorials by 402PaymentRequired

Video Channels

Video Podcasts

Podcast Description
Satoshi en Venezuela Spanish Bitcoin News
Simply Bitcoin Daily Bitcoin News

Tutorials

Class Description
402PaymentRequired Step by step Bitcoin software tutorials.
Bitcoinheiros Brazilian Portuguese Videos and Tutorials
KIS Bitcoin Keep It Simple - Practical Guides
Wasabi Series Max Hillebrand's Wasabi Wallet Guide

Other Informative

Channel Description
Advancing Bitcoin 11 Superb Presentations *
BitKnow Interviews
Bolt-A-Thon 9 Superb Presentations + Hackathon
Hungry Hodler Engaging, Informative Bitcoin Videos
Justin Moon Interviews & Presentations
Learn Me A Bitcoin 4 Superb Explainer Videos

* Skip 'The Difficulties in ...' & 'Bitcoin Engineering ...' (poor audio)

Companies

Channel Description
Amber Aleks Svetski & Amber Promo
Bull Bitcoin Francis Pouliot & Bull Bitcoin Promo

Getting Started:
For a non-technical intro read 'The Bitcoin Standard' by Saifedean Ammous (Hardcopy)
For a technical intro read 'Grokking Bitcoin' by Kalle Rosenbaum (Hardcopy | GitHub)
For further technical info read 'Programming Bitcoin' by Jimmy Song (Hardcopy | GitHub)

Books

These books explicitly cover bitcoin only.

Book Synopsis Author
The Bitcoin Standard (Hardcopy) Essential reading. Saifedean Ammous
Inventing Bitcoin (Kindle / PDF) Beginner's intro to bitcoin. Yan Pritzker
Bitcoin Money (Direct , Amazon) Bitcoin Story Book for Kids Michael Caras
Grokking Bitcoin (Direct) Illustrated Bitcoin Explainer Kalle Rosenbaum
The Little Bitcoin Book (Direct , Amazon) Intro to Bitcoin Alex Gladstein , Jimmy Song
Q/A about Bitcoin (Direct , Amazon) Common Questions and Answers David Coen
Sovereignty Through Mathematics (Amazon) Properties of Bitcoin Knut Svanholm

More technical resources can be found in dev-tools.

Periodicals

These periodicals explicitly cover bitcoin only.

Class Description
Lightning Hood Round Up Weekly Summary of Bitcoin and Lightning Network News
The Bitcoin Times A Beautiful, Informative and Stylish Publication released 2-3 times per year.

Classes

These classes explicitly cover bitcoin only.

Class Description
21 Lectures (Beginner) 2-day Course (In development)
21 Lectures (Advanced) 4-day Course
Bitcoin Studio 1-day Workshops
Buidl Bootcamp 6-week Course (20h/week) online
Learn Me A Bitcoin 1-day Workshop
Programming Blockchain 2-day Seminar
Programming With Bitcoin 2-day Workshop
Smart Custody 1-day Workshop
Teach Bitcoin 4-week Course (10h/week) online
The Bitcoin Standard Academy 10-week Course online

Websites

These websites explicitly cover bitcoin only.

Class Description
10hoursofbitcoin Links to 10h of Bitcoin Lessons
21lessons Superb Bitcoin Lessons (Audio 1|2|3)
Background Reading Understanding the technical side of bitcoin
Bitcoin Designed Striking Bitcoin Infographics
Bitcoin Q & A Extensive Questions & Answers
Bitcoin Rabbit Hole Index of Bitcoin Content
Bitcoin Slides Comprehensive Slides
Bitcoin Translated Russian Translations of Articles & Books
Bitcoin.org Bitcoin information
BitKnow Quality Bitcoin Blog
Chaincode Study Groups Bitcoin & Lightning study guides
Hungry Hodler Informative Bitcoin Evangelizing
L2B Global Blog from an OTC desk
Learn Me A Bitcoin Bitcoin Explained
Look Into Bitcoin Live valuation charts
Ministry Of Nodes Articles, Videos and Workshops/Webinars
Nakamoto Institute Everything Satoshi
River Learning Center Basics Guide & Glossary
Towards Liberty Open Source Bitcoin Archive
Veriphi Bitcoin Tech Explained
Why Hold Bitcoin Reviews, Guides & Resources
WORDS A monthly Bitcoin journal

Advanced Reading

Class Description
Bitcoin Questions Technical Bitcoin questions
Lightning Summary Lightning network deep-dive
Schnorr / MuSig Max's Cliffnotes
Shamir Secret Sharing Max's Cliffnotes


Podcasts

See the dedicated Podcast section.

Getting Started:
First listen to 'SLP71: Intro to Bitcoin Austrian Thought' by Stephan Livera

Podcasts

These podcasts explicitly cover bitcoin only.

Podcast Description
Bitcoin Audible Narrations of the best bitcoin articles
Bitcoin Echo Chamber Interviews with Bitcoiners
Bitcoinheiros Brazilian Portuguese Podcast
Bitcoin Matters Conversations with @Beautyon_
Bitcoin Rapid Fire Interviews with Bitcoiners
Bitcoin Rehab Interviews with Bitcoiners
Blockdigest Casual bitcoin news podcast
Bottomshelf Bitcoin Putting Bitcoin within everyone's reach
The Chaincode Podcast Interviews with Bitcoin Engineers
Citizen Bitcoin Interviews with Bitcoiners
De Bitcoin Show Dutch weekly bitcoin news
Fun With Bitcoin Interviews with Bitcoiners
Noded Michael Goldstein and Pierre Rochard
Reckless Review Lawrence Nahum & Udi Wertheimer
Stephan Livera Bitcoin and Austrian Economics
Swan Signal Interviews with Bitcoiners
TFTC21 Tales from the crypt
The Bitcoin Basics Podcast Bitcoin for Beginners
The Chaincode Podcast Interviews with Bitcoin Engineers
The Bitcoin Standard Podcast Weekly Bitcoin & Economics Seminars w/ Saifedean Ammous
The Total Connector Interviews with Bitcoiners

Getting Started:
Check tx's with Blockstream.info & the mempool with Mempool.Space

Network

Explorers

These explorers support bitcoin only.

Name Description
Blockstream.info Simple Blockchain Explorer
BTC RPC Opensource Bitcoin Explorer
OXT Advanced Blockchain Explorer
Yogh Explorer Bitcoin Blockchain Reader

Fees / Mempool

Name Description
Bitcoiner Live Simple Fee Estimation
What The Fee Simple Fee Estimation
Bitcoinrain Mempool Visualisation
BTC moe Mempool Visualisation
Mempool.Space Mempool / Block Visualisation & Fee Charts
Mempool.Observer Mempool / Block Visualisation & Fee Charts
What The Fee Simple Fee Estimation

Metrics

Name Description
Bitcoin Treasuries Publicly-Traded Companies Holding Bitcoin
Clark Moody Dashboard Bitcoin & LN Metrics

Getting Started:
Earn bitcoin with MicroLancer

Get Bitcoin

You can get bitcoin using these services.

Earn

Name Description
jfgi [*] Bitcoin Fundraising
LNDwork Micro-Freelancing
MicroLancer Micro-Freelancing
Paywall Link Easily paywall content
TallyCoin [*] Bitcoin Fundraising
GiveBitcoin Give, Request and Earn

[*] : Tallycoin & jfgi could at any time swap out your donation address for their own.

Cashback

Name Description
Fold App Bitcoin Cashback Rewards
Lolli Bitcoin Cashback Rewards

Buy

You can buy a fraction of a bitcoin, so don't let a high price per bitcoin put you off. Many people are #stackingsats (regularly spending a fixed $ amount on buying bitcoin, also known as Dollar Cost Averaging), you can see that this method has historically been a good way of accumulating bitcoin by looking at dcabtc.com & hodl.camp.

Name Description
HodlHodl Non-KYC | P2P | Non-Custodial
LocalCryptos Non-KYC | P2P | Non-Custodial
Bisq Open source | Decentralized
Pocketbits KYC | Custodial
Wazirx KYC | Custodial
CoinDCX KYC | Custodial
Giottus KYC | Custodial
Unocoin KYC | Custodial

Do your own research as well before using any exchange. Not your keys not your bitcoin.


Mine

Long gone are the days that you could mine Bitcoin using common hardware. Bitcoin mining is now dominated by specialist hardware powered by low cost electricity. This video gives a simple overview.

Getting Started:
Bitcoin enables anyone to tap into a truly global marketplace.
Consider the impact on your privacy if you buy goods which link to your identity or require physical delivery. It's best to avoid getting things delivered to your home address for this reason.

Spend Bitcoin

Tools

Name Description
Bitrefill Purchase Gift Cards or Mobile Refills from more than 1650 businesses in 170 countries
Bitscribble Write 40 bytes of data to the blockchain
BullBitcoin Non-Custodial Bitcoin Services
Bylls Pay Bills (Canada)
Fold App Buy Vouchers with Bitcoin Cashback
Host4Coins VPS Hosting
Njalla Domain Name Registration Service
Kriptode Lightning Tools
LNsms Send texts worldwide and pay with Lightning
Spacebit Send messages via satellite
Woleet Timestamping Service

Fun & Play

Name Description
Kriptode Lightning Games
LNgames.net Lightning Games
Moneni Lightning Games
Lightning Puzzle Set / Solve Puzzles
Pollo Feed Feed Chickens
Satoshis Game Of Life Conway's Game of Life
Satoshis Games Original Lightning Games
Satoshis Place Lightning Canvas

Remember to check that gambling sites are fair, fairlightning.network helps check this.

Stores and Services

Name Description
Cheapair Book flight tickets
Travala Book Hotels
1.21 Jigawatts Stamps, Stickers & More
21X Bitcoin Art, Designs, and Merchandise
Arnhem Bitcoin City A Bitcoin Friendly City
Bitcoin Merit Badge Bitcoin Badges
Bitcoin Shirt Bitcoin Merchandise
Bitcoin Tunnels Clothing, Mugs & More
Bitko Yinowsky Stickers
CryptoCloaks 3D Printed Cases & Custom Nodes
DIYnodes Bitcoin Nodes & More
Koala Stickers Stickers
Layer One BTC Bitcoin apparel and more
Liberty Mugs Mugs, T-shirts & More
Lightning Hood Consultation, T-shirts & More
Lightning Hosted Simple Image Hosting
Moneybadger Shop T-shirts, Mugs & More
Mt. Socks Socks
Original Satoshi Stickers & More
PirateHash Bitcoin curiosities and educational materials.
Quinsolo Coasters, Magnets & More
Start 2 Bitcoin Fun Bitcoin Info Pack
Von Bitcoin T-Shirts, Prints, & More
Wears My Liberty Liberty Shirts, Hats, Hoodies & More
White Rabbit Store Bitcoin Bookmarks & Accessories

Remind yourself of the buying power of a Satoshi with cent2sat.

Store Tools

These tools help you accept bitcoin.

Name Description
BTCPay Server Open source Bitcoin payment processor
Blockonomics Permissionless Bitcoin payment solution
BullBitcoin Non-Custodial Bitcoin Services
chainside Payments Processor
opennode Payments Processor *
paid.co Sell things for Bitcoin (uses OpenNode) *

[*] : Opennode is fully custodial meaning you do not have your private keys, thus you are not guaranteed full control of your funds. You can (and should) set reoccurring withdrawals to send any bitcoin you receive to your own wallet. You are now also required to submit KYC Documentation to be an Opennode merchant.

Conferences

These conferences are bitcoin only.

Getting Started:
Read my FAQ on how to Hold bitcoin Privately.

Privacy

Preserve your privacy when using bitcoin.

CoinJoin Tools

Name Unique Perks Learn More
Joinmarket Market based fee structure. Text | Video | Audio
Wasabi Wallet Strong network level privacy. Text | Video | Audio
Whirlpool Advanced postmix spending Text | Video | Audio

Communication Tools

Name Unique Perks Learn More
Juggernaut End-to-end encrypted messaging over the lightning network. Text

information

Contact

Have any questions? Need some help? Follow on Twitter and Subscribe to Youtube channel.

Youtube | Twitter | Soundcloud

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