title: Blockchain! Blockchain! Blockchain! - Build Your Own Blockchains in Ruby from Zero (Scratch)
Transactions (Hyper) Ledger Book
| From | To | Amount |
|---|---|---|
| Grossklockner (†) | Sepp | 3798 |
| Grossvenediger (†) | Franz | 3666 |
| Dachstein (†) | Sissi | 2995 |
| Wildspitze (†) | Maria | 3768 |
| Sissi | Eva | 20 |
| Sepp | Maria | 17 |
| Franz | Sissi | 3 |
| Sepp | Ferdl | 100 |
| Franz | Max | 17 |
| Maria | Adam | 4 |
(†): Miner Transaction - New Schilling on the Market!
(Source: blockchainaustria/schilling)
Blockchain! Blockchain! Blockchain! Decentralize Payments. Decentralize Transactions. Decentralize Blockchains.
What's Blockchain?
- Distributed Database?
- Hyper Ledger Book?
- Consensus with Proof-of-Work or Proof-of-Stake?
- Digital Fingerprints? Cryptographic Hashes?
- Lottery? Central Bank?
- Byzantine-Generals Solution?
Yes. Yes. Yes. Blockchain! Blockchain! Blockchain!
(Source: openblockchains/whatsblockchain)
A Success Story on the Blockchain.
May 22, 2010 - World's 1st Bitcoin Payment
A developer bought two pizzas using 10 000 Bitcoin (BTC) - a then-little-known digital (crypto)currency. Estimated worth about $40.
Triva Q: How much is one Bitcoin worth today? Q: How much are 10 000 Bitcoin worth today?
(Source: coinmarketcap.com/currencies/bitcoin)
Crypto God? Ruby Ninja / Rockstar?
Yes, you can.
What's Blockchain?
It's a list (chain) of blocks linked and secured by digital fingerprints (also known as crypto hashes).
require "digest" # for hash checksum digest function SHA256
class Block
attr_reader :index
attr_reader :timestamp
attr_reader :data
attr_reader :previous_hash
attr_reader :hash
def initialize(index, data, previous_hash)
@index = index
@timestamp = Time.now
@data = data
@previous_hash = previous_hash
@hash = calc_hash
end
def calc_hash
sha = Digest::SHA256.new
sha.update( @index.to_s + @timestamp.to_s + @data + @previous_hash )
sha.hexdigest
end(Source: openblockchains/awesome-blockchains/blockchain.rb)
Yes, that's it.
Let's add two helpers (first, next) for building ("mining") blocks.
class Block
def self.first( data="Genesis" ) # create genesis (big bang! first) block
## uses index zero (0) and arbitrary previous_hash ("0")
Block.new( 0, data, "0" )
end
def self.next( previous, data="Transaction Data..." )
Block.new( previous.index+1, data, previous.hash )
end
end # class Block(Source: openblockchains/awesome-blockchains/blockchain.rb)
Let's get started - build a blockchain a block at a time!
b0 = Block.first( "Genesis" )
b1 = Block.next( b0, "Transaction Data..." )
b2 = Block.next( b1, "Transaction Data......" )
b3 = Block.next( b2, "More Transaction Data..." )
blockchain = [b0, b1, b2, b3]
pp blockchain ## pp (pretty print to console)Wait, so a blockchain is just a linked list?
No. A linked list is only required to have a reference to the previous element, a block must have an identifier depending on the previous block's identifier, meaning that you cannot replace a block without recomputing every single block that comes after. In this implementation that happens as the previous digest is input in the calc_hash method.
will log something like:
[#<Block:0x1eed2a0
@index = 0,
@timestamp = 1637-09-15 20:52:38,
@data = "Genesis",
@previous_hash = "0",
@hash = "edbd4e11e69bc399a9ccd8faaea44fb27410fe8e3023bb9462450a0a9c4caa1b">,
#<Block:0x1eec9a0
@index = 1,
@timestamp = 1637-09-15 21:02:38,
@data = "Transaction Data...",
@previous_hash = "edbd4e11e69bc399a9ccd8faaea44fb27410fe8e3023bb9462450a0a9c4caa1b",
@hash = "eb8ecbf6d5870763ae246e37539d82e37052cb32f88bb8c59971f9978e437743">,
#<Block:0x1eec838
@index = 2,
@timestamp = 1637-09-15 21:12:38,
@data = "Transaction Data......",
@previous_hash = "eb8ecbf6d5870763ae246e37539d82e37052cb32f88bb8c59971f9978e437743",
@hash = "be50017ee4bbcb33844b3dc2b7c4e476d46569b5df5762d14ceba9355f0a85f4">,
...
Making (Hash) Mining a Lottery - Find the Lucky Number
def calc_hash
sha = Digest::SHA256.new
sha.update( @index.to_s + @timestamp.to_s + @data + @previous_hash )
sha.hexdigest
endThe computer (node) in the blockchain network that computes the next block with a valid hash wins the lottery.
For adding a block to the chain you get a reward! You get 25 12.5 Bitcoin! (†)
Bitcoin adds a block every ten minutes.
(†) The reward gets halfed about every two years. In Sep'17 you'll get 12.5 Bitcoin.
Random SHA256 hash #1: c396de4c03ddb5275661982adc75ce5fc5905d2a2457d1266c74436c1f3c50f1
Random SHA256 hash #2: 493131e09c069645c82795c96e4715cea0f5558be514b5096d853a5b9899154a
Triva Q: What's SHA256?
- (A) Still Hacking Anyway
- (B) Secure Hash Algorithm
- (C) Sweet Home Austria
- (D) Super High Aperture
A: SHA256 == Secure Hash Algorithms 256 Bits
Trivia: Designed by the National Security Agency (NSA) of the United States of America (USA).
Secure == Random e.g. Change one Letter and the Hash will Change Completely
Making (Hash) Mining a Lottery - Find the Lucky Number
Find a hash that starts with ten leading zeros e.g.
0000000000069645c82795c96e4715cea0f5558be514b5096d853a5b9899154a
Hard to compute! Easy to check / validate.
Making (Hash) Mining a Lottery - Find the Lucky Number (Nonce)
def compute_hash_with_proof_of_work( difficulty="00" )
nonce = 0
loop do
hash = calc_hash_with_nonce( nonce )
if hash.start_with?( difficulty )
return [nonce,hash] ## bingo! proof of work if hash starts with leading zeros (00)
else
nonce += 1 ## keep trying (and trying and trying)
end
end
end
def calc_hash_with_nonce( nonce=0 )
sha = Digest::SHA256.new
sha.update( nonce.to_s + @index.to_s + @timestamp.to_s + @data + @previous_hash )
sha.hexdigest
end(Source: awesome-blockchains/blockchain_with_proof_of_work.rb)
Let's rerun the sample with the proof of work machinery added. Now the sample will pretty print (pp) something like:
[#<Block:0x1e204f0
@index = 0,
@timestamp = 1637-09-20 20:13:38,
@data = "Genesis",
@previous_hash = "0",
@nonce = 242,
@hash = "00b8e77e27378f9aa0afbcea3a2882bb62f6663771dee053364beb1887e18bcf">,
#<Block:0x1e56e20
@index = 1,
@timestamp = 1637-09-20 20:23:38,
@data = "Transaction Data...",
@previous_hash = "00b8e77e27378f9aa0afbcea3a2882bb62f6663771dee053364beb1887e18bcf",
@nonce = 46,
@hash = "00aae8d2e9387e13c71b33f8cd205d336ac250d2828011f5970062912985a9af">,
#<Block:0x1e2bd58
@index = 2,
@timestamp = 1637-09-20 20:33:38,
@data = "Transaction Data......",
@previous_hash = "00aae8d2e9387e13c71b33f8cd205d336ac250d2828011f5970062912985a9af",
@nonce = 350,
@hash = "00ea45e0f4683c3bec4364f349ee2b6816be0c9fd95cfd5ffcc6ed572c62f190">,
...
See the difference?
All hashes now start with leading zeros (00)
and the nonce is the random "lucky number" that makes it happen.
That's the magic behind the proof of work.
- Uses approximately the same amount of electricity as could power an average American household for a day per transaction
- Supports 3 transactions / second across a global network with millions of CPUs/purpose-built ASICs
- Takes over 10 minutes to "commit" a transaction
- Doesn't acknowledge accepted writes: requires you read your writes, but at any given time you may be on a blockchain fork, meaning your write might not actually make it into the "winning" fork of the blockchain (and no, just making it into the mempool doesn't count). In other words: "blockchain technology" cannot by definition tell you if a given write is ever accepted/committed except by reading it out of the blockchain itself (and even then)
- Can only be used as a transaction ledger denominated in a single currency, or to store/timestamp a maximum of 80 bytes per transaction
(Source: Tony Arcieri - On the dangers of a blockchain monoculture)
Q: Tulip Mania Bubble in Holland - What Year?
- (A) 1561
- (B) 1637
- (C) 1753
- (D) 1817
Q: What's the Name of the Most Expensive Tulip?
- (A) Admiral van Eijck
- (B) Admiral of Admirals
- (C) Semper Augustus
- (C) Semper Cesarus
Learn by Example from the Real World (Anno 1637) - Buy! Sell! Hold! Enjoy the Beauty of Admiral of Admirals, Semper Augustus and More.
Transactions (Hyper) Ledger Book
| From | To | What | Qty |
|---|---|---|---|
| Dutchgrown (†) | Vincent | Tulip Bloemendaal Sunset | 10 |
| Keukenhof (†) | Anne | Tulip Semper Augustus | 7 |
| Flowers (†) | Ruben | Tulip Admiral van Eijck | 5 |
| Vicent | Anne | Tulip Bloemendaal Sunset | 3 |
| Anne | Julia | Tulip Semper Augustus | 1 |
| Julia | Luuk | Tulip Semper Augustus | 1 |
| Bloom & Blossom (†) | Daisy | Tulip Admiral of Admirals | 8 |
| Vincent | Max | Tulip Bloemendaal Sunset | 2 |
| Anne | Martijn | Tulip Semper Augustus | 2 |
| Ruben | Julia | Tulip Admiral van Eijck | 2 |
| Teleflora (†) | Max | Tulip Red Impression | 11 |
| Anne | Naomi | Tulip Bloemendaal Sunset | 1 |
| Daisy | Vincent | Tulip Admiral of Admirals | 3 |
| Julia | Mina | Tulip Admiral van Eijck | 1 |
| Max | Isabel | Tulip Red Impression | 2 |
(†): Grower Transaction - New Tulips on the Market!
(Source: openblockchains/tulips)
Quotes - Blockchains are the next Internets / Tulips
People who compare digital tokens to tulips are essentially saying digital tokens are a bubble backed by nothing but pure hype and speculation.
What they fail to understand is that tulips come from dirt, not a blockchain.
And as we all know, blockchain is possibly the best technological innovation since the internet. It will have a tremendous impact on global business and society in general. -- TulipToken
b0 = Block.first(
{ from: "Dutchgrown", to: "Vincent", what: "Tulip Bloemendaal Sunset", qty: 10 },
{ from: "Keukenhof", to: "Anne", what: "Tulip Semper Augustus", qty: 7 } )
b1 = Block.next( b0,
{ from: "Flowers", to: "Ruben", what: "Tulip Admiral van Eijck", qty: 5 },
{ from: "Vicent", to: "Anne", what: "Tulip Bloemendaal Sunset", qty: 3 },
{ from: "Anne", to: "Julia", what: "Tulip Semper Augustus", qty: 1 },
{ from: "Julia", to: "Luuk", what: "Tulip Semper Augustus", qty: 1 } )
b2 = Block.next( b1,
{ from: "Bloom & Blossom", to: "Daisy", what: "Tulip Admiral of Admirals", qty: 8 },
{ from: "Vincent", to: "Max", what: "Tulip Bloemendaal Sunset", qty: 2 },
{ from: "Anne", to: "Martijn", what: "Tulip Semper Augustus", qty: 2 },
{ from: "Ruben", to: "Julia", what: "Tulip Admiral van Eijck", qty: 2 } )
...resulting in:
[#<Block:0x2da3da0
@hash="32bd169baebba0b70491b748329ab631c85175be15e1672f924ca174f628cb66",
@index=0,
@previous_hash="0",
@timestamp=1637-09-25 17:39:21,
@transactions=
[{:from=>"Dutchgrown", :to=>"Vincent", :what=>"Tulip Bloemendaal Sunset", :qty=>10},
{:from=>"Keukenhof", :to=>"Anne", :what=>"Tulip Semper Augustus", :qty=>7}],
@transactions_count=2>,
#<Block:0x2da2ff0
@hash="57b519a8903e45348ac8a739c788815e2bd90423663957f87e276307f77f1028",
@index=1,
@previous_hash=
"32bd169baebba0b70491b748329ab631c85175be15e1672f924ca174f628cb66",
@timestamp=1637-09-25 17:49:21,
@transactions=
[{:from=>"Flowers", :to=>"Ruben", :what=>"Tulip Admiral van Eijck", :qty=>5},
{:from=>"Vicent", :to=>"Anne", :what=>"Tulip Bloemendaal Sunset", :qty=>3},
{:from=>"Anne", :to=>"Julia", :what=>"Tulip Semper Augustus", :qty=>1},
{:from=>"Julia", :to=>"Luuk", :what=>"Tulip Semper Augustus", :qty=>1}],
@transactions_count=4>,
...
blockchain-lite library (github: openblockchains/blockchain.lite.rb, gem: blockchain-lite) -
build your own blockchain with crypto hashes -
revolutionize the world with blockchains, blockchains, blockchains one block at a time
Usage
Let's get started. Build your own blockchain one block at a time.
require 'blockchain-lite'
b0 = Block.first( 'Genesis' )
b1 = Block.next( b0, 'Transaction Data...' )
b2 = Block.next( b1, 'Transaction Data......' )
b3 = Block.next( b2, 'More Transaction Data...' )
blockchain = [b0, b1, b2, b3]
pp blockchain
(Source: coinmarketcap.com/currencies/gulden)
Who's in? Invest now!
Crypto #Schilling on the #Blockchain in 324 Days 7 Hours 30 Minutes!
Join the Rock-Solid Alpine Dollar Movement!
Learn more @ blockchainaustria/schilling
Collectible. Breedable. Adorable.
Collect and breed digital cats. Start meow. Buy! Sell! Hold!
Learn more @ cryptokitties.co
Latest (and Greatest) Investment Opportunity!
Blockchain has unlocked the magic of digital scarcity, and combining that with the power of making the digital goods persistent gives them a potential value that is only limited by how much prestige a wealthy person might place on ownership of the item.
-- Justin Poirier
All I want for Christmas is a CryptoKitty.
I got a fever. And the only prescription is more CryptoKitties.
My Gen 7 CryptoKitty #104375. The Future is Meow.
Reflections on the Blockchain by Rufus Pollock (Open Knowledge Foundation), July 2016 -- The DAO: Code is not Law – and It’s Dangerous to Think So ++ The Internet changed the world - surely the Blockchain will too? ++ Gold-rush or Internet-rush? ++ Governance Matters in Bitcoin ++ The Myth of a Costless, Ownerless Network ++ Lessons from History
On the Dangers of a Blockchain Monoculture by Tony Arcieri, January 2016 -- The Bitcoin blockchain: the world's worst database ++ Next-generation protocols ++ Decentralized ledger protocols ++ Bitcoin-NG ++ Blockchain! Blockchain! Blockchain! ++ The great decentralized database in the sky
I Don't Believe in Blockchain by Tim Bray, May 2017
Minimum Viable Blockchain by Ilya Grigorik, May 2014 -- Securing transactions with triple-entry bookkeeping ++ Securing transactions with PKI ++ Balance = Σ(receipts) ++ Multi-party transfers & verification ++ Double-spending and distributed consensus - Requirements for a distributed consensus network; Protecting the network from Sybil attacks; Proof-of-work as a participation requirement ++ Building the minimum viable blockchain - Adding "blocks" & transaction fee incentives; Racing to claim the transaction fees; Resolving chain conflicts; Blocks are never final ++ Properties of the (minimum viable) blockchain
Blockchains by analogies and applications: How blockchain compares to Git, Raft, and other technologies. by Kieren James-Lubin, January 2016 -- Blockchains are databases ++ Understanding transactions ++ Persistent, replicated databases (related technology: Git) ++ Peer-to-peer networks (related technology: BitTorrent) ++ Distributed consensus (related technology: distributed databases, Raft) ++ Minting new coins (mining) ++ Embedded identities (related technology: TLS) ++ Smart contracts: Like SQL expressions & triggers ++ What can we really do with blockchains?
Attack of the 50 Foot Blockchain: Bitcoin, Blockchain, Ethereum & Smart Contracts by David Gerard, London, 2017 -- What is a bitcoin? ++ The Bitcoin ideology ++ The incredible promises of Bitcoin! ++ Early Bitcoin: the rise to the first bubble ++ How Bitcoin mining centralised ++ Who is Satoshi Nakamoto? ++ Spending bitcoins in 2017 ++ Trading bitcoins in 2017: the second crypto bubble ++ Altcoins ++ Smart contracts, stupid humans ++ Business bafflegab, but on the Blockchain ++ Case study: Why you can’t put the music industry on a blockchain
Mastering Bitcoin - Programming the Open Blockchain 2nd Edition, by Andreas M. Antonopoulos, 2017 - FREE (Online Source Version) -- What Is Bitcoin? ++ How Bitcoin Works ++ Bitcoin Core: The Reference Implementation ++ Keys, Addresses ++ Wallets ++ Transactions ++ Advanced Transactions and Scripting ++ The Bitcoin Network ++ The Blockchain ++ Mining and Consensus ++ Bitcoin Security ++ Blockchain Applications
Blockchain for Dummies, IBM Limited Edition by Manav Gupta, 2017 - FREE (Digital Download w/ Email) -- Grasping Blockchain Fundamentals ++ Taking a Look at How Blockchain Works ++ Propelling Business with Blockchains ++ Blockchain in Action: Use Cases ++ Hyperledger, a Linux Foundation Project ++ Ten Steps to Your First Blockchain application
A collection about awesome blockchains - open distributed public databases w/ crypto hashes incl. git ;-). Blockchains are the new tulips. Distributed is the new centralized.
More @ openblockchains/awesome-blockchains
Everything is local. Distributed is the new centralized.
Yep, that's the joke. Nobody has been able to explain to me how the "blockchain" buzzword is significantly different to "git repo". -- Yaakov
But if you said "let's build a currency where all transactions are stored in a git repo" you wouldn't be taken seriously for even 24 hrs. -- Yaakov
Soon explaining git like "a git repo is like a blockchain with commits instead of blocks". -- Nicolás Berger
"A local branch is like a state channel. It can be pushed and merged into the master blockchain at any moment." -- Nicolás Berger
The #Blockchain has changed the world. Here I make the argument that the #Blockchain is just like #git. -- Jackson Kelley
git merge [-m REF] [-g BLOB] --pushMerge and push all signed commits to the blockchain. -- Git Commands