Mining Digital Gold one Block at a Time?! • Don't Expect to Get Insanely Rich (Quick) • Tulips 🌷🌷🌷 (like Blockchains) are Great and Gorgeous (and will Endure)
A collection about awesome blockchains - open distributed databases w/ crypto hashes incl. git ;-). Blockchains are the new tulips 🌷🌷🌷.
Contents:
- Frequently Asked Questions (F.A.Q.s) & Answers
- Articles
- Books
- Do-It-Yourself (DIY) - Build Your Own Blockchain
- Blockchain (Lite) Crypto Hash Libraries
- Git, Git, Git - The Stupid Content Tracker with Crypto Hashes
- Classic Tulip Mania
Q: What's a Blockchain?
A: A blockchain is a distributed database with a linked list (that is, chain) of records (that is, blocks) secured by crypto(graphic) hashes.
Q: What's a Merkle Tree?
A: A Merkle tree is a hash tree named after Ralph Merkle who patented the concept in 1979 (the patent expired in 2002). A hash tree is a generalization of hash lists or hash chains where every leaf node (in the tree) is labelled with a data block and every non-leaf node (in the tree) is labelled with the crypto(graphic) hash of the labels of its child nodes. For more see the Merkle tree Wikipedia Article.
Note: By adding crypto(graphic) hash functions you can "merkelize" any data structure.
Q: What's a Merkelized DAG (Directed Acyclic Graph)?
A: It's a blockchain secured by crypto(graphic) hashes that uses a directed acyclic graph data structure (instead of linear "classic" linked list).
Note: Git uses merkelized dag (directed acyclic graph)s for its blockchains.
Q: Is the Git Repo a Blockchain?
A: Yes, every branch in the git repo is a blockchain. The "classic" Satoshi-blockchain is like a git repo with a single master branch (only).
Q: What's a Hash? What's a (One-Way) Crypto(graphic) Hash Digest Checksum?
A: A hash e.g. eb8ecbf6d5870763ae246e37539d82e37052cb32f88bb8c59971f9978e437743
is a small digest checksum calculated
with a one-way crypto(graphic) hash digest checksum function
e.g. SHA256 (Secure Hash Algorithm 256 Bits)
from the data. Example from blockchain.rb:
def calc_hash
sha = Digest::SHA256.new
sha.update( @index.to_s + @timestamp.to_s + @data + @previous_hash )
sha.hexdigest ## returns "eb8ecbf6d5870763ae246e37539d82e37052cb32f88bb8c59971f9978e437743"
endA blockchain uses
- the block index (e.g.
1,2,3,4, etc.) and - the block timestamp (e.g.
2017-09-15 20:52:38) and - the block data (e.g.
Transaction Data...) and finally - the hash from the previous block (e.g.
edbd4e11e69bc399a9ccd8faaea44fb27410fe8e3023bb9462450a0a9c4caa1b)
to calculate the new hash digest checksum, that is, the hash
e.g. be50017ee4bbcb33844b3dc2b7c4e476d46569b5df5762d14ceba9355f0a85f4.
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?
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
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
Let's Build the Tiniest Blockchain In Less Than 50 Lines of Python by Gerald Nash, July 2016
Let's Make the Tiniest Blockchain Bigger With More Lines of Python (Part 2) by Gerald Nash, July 2016
Writing a Tiny Blockchain in JavaScript by Xavier Decuyper, July 2017
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 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
private
def calc_hash
sha = Digest::SHA256.new
sha.update( @index.to_s + @timestamp.to_s + @data + @previous_hash )
sha.hexdigest
end
end # class Block
#####
## 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(Source: blockchain.rb)
will pretty print (pp) something like:
[#<Block:0x1eed2a0
@index = 0,
@timestamp = 2017-09-15 20:52:38,
@data = "Genesis",
@previous_hash = "0",
@hash = "edbd4e11e69bc399a9ccd8faaea44fb27410fe8e3023bb9462450a0a9c4caa1b">,
#<Block:0x1eec9a0
@index = 1,
@timestamp = 2017-09-15 20:52:38,
@data = "Transaction Data...",
@previous_hash = "edbd4e11e69bc399a9ccd8faaea44fb27410fe8e3023bb9462450a0a9c4caa1b",
@hash = "eb8ecbf6d5870763ae246e37539d82e37052cb32f88bb8c59971f9978e437743">,
#<Block:0x1eec838
@index = 2,
@timestamp = 2017-09-15 20:52:38,
@data = "Transaction Data......",
@previous_hash = "eb8ecbf6d5870763ae246e37539d82e37052cb32f88bb8c59971f9978e437743",
@hash = "be50017ee4bbcb33844b3dc2b7c4e476d46569b5df5762d14ceba9355f0a85f4">,
#<Block:0x1eec6d0
@index = 3,
@timestamp = 2017-09-15 20:52:38,
@data = "More Transaction Data...",
@previous_hash = "be50017ee4bbcb33844b3dc2b7c4e476d46569b5df5762d14ceba9355f0a85f4",
@hash = "5ee2981606328abfe0c3b1171440f0df746c1e1f8b3b56c351727f7da7ae5d8d">]
Comments from the reddit ruby posting:
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.
What about Proof of Work?
Let's add a proof of work to the blockchain. In the classic blockchain you have to compute a block hash that starts with leading zeros (00). The more leading zeros the harder (more difficult) to compute. Let's keep it easy to compute with two leading zeros (00), that is, 16^2 = 256 possibilites. Three leading zeros (000) would be 16^3 = 4_096 possibilites and four zeros (0000) would be 16^4 = 65_536 and so on. Example:
def compute_hash_with_proof_of_work
nonce = 0
loop do
hash = calc_hash_with_nonce( nonce )
if hash.start_with?( "00" )
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: 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 = 2017-09-20 20:13:38,
@data = "Genesis",
@previous_hash = "0",
@nonce = 242,
@hash = "00b8e77e27378f9aa0afbcea3a2882bb62f6663771dee053364beb1887e18bcf">,
#<Block:0x1e56e20
@index = 1,
@timestamp = 2017-09-20 20:13:38,
@data = "Transaction Data...",
@previous_hash = "00b8e77e27378f9aa0afbcea3a2882bb62f6663771dee053364beb1887e18bcf",
@nonce = 46,
@hash = "00aae8d2e9387e13c71b33f8cd205d336ac250d2828011f5970062912985a9af">,
#<Block:0x1e2bd58
@index = 2,
@timestamp = 2017-09-20 20:13:38,
@data = "Transaction Data......",
@previous_hash = "00aae8d2e9387e13c71b33f8cd205d336ac250d2828011f5970062912985a9af",
@nonce = 350,
@hash = "00ea45e0f4683c3bec4364f349ee2b6816be0c9fd95cfd5ffcc6ed572c62f190">,
#<Block:0x1fa8338
@index = 3,
@timestamp = 2017-09-20 20:13:38,
@data = "More Transaction Data...",
@previous_hash = "00ea45e0f4683c3bec4364f349ee2b6816be0c9fd95cfd5ffcc6ed572c62f190",
@nonce = 59,
@hash = "00436f0fca677652963e904ce4c624606a255946b921132d5b1f70f7d86c4ab8">]
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.
class Block {
constructor(index, data, previousHash) {
this.index = index
this.timestamp = new Date()
this.data = data
this.previousHash = previousHash
this.hash = this.calcHash()
}
calcHash() {
var sha = SHA256.create()
sha.update( this.index.toString() + this.timestamp.toString() + this.data + this.previousHash )
return sha.hex()
}
static first( data="Genesis" ) { // create genesis (big bang! first) block
// uses index zero (0) and arbitrary previousHash ("0")
return new Block( 0, data, "0" )
}
static next( previous, data="Transaction Data..." ) {
return new Block( previous.index+1, data, previous.hash )
}
}
//////
// 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]
console.log( blockchain )(Source: blockchain.js)
will log something like:
[ Block {
index : 0,
timestamp : 2017-09-18T08:25:54.162Z,
data : 'Genesis',
previousHash : '0',
hash : 'c396de4c03ddb5275661982adc75ce5fc5905d2a2457d1266c74436c1f3c50f1' },
Block {
index : 1,
timestamp : 2017-09-18T08:25:54.178Z,
data : 'Transaction Data...',
previousHash : 'c396de4c03ddb5275661982adc75ce5fc5905d2a2457d1266c74436c1f3c50f1',
hash : '493131e09c069645c82795c96e4715cea0f5558be514b5096d853a5b9899154a' },
Block {
index : 2,
timestamp : 2017-09-18T08:25:54.178Z,
data : 'Transaction Data......',
previousHash : '493131e09c069645c82795c96e4715cea0f5558be514b5096d853a5b9899154a',
hash : '97aa3cb5052615d60ff8e6b41bef606562588c4874f011970ac2f218e2f0f4a8' },
Block {
index : 3,
timestamp : 2017-09-18T08:25:54.178Z,
data : 'More Transaction Data...',
previousHash : '97aa3cb5052615d60ff8e6b41bef606562588c4874f011970ac2f218e2f0f4a8',
hash : 'e10e020f832e46c2b60e1c3c0412bd370b2fde5f0f782c16eb87d0313ea0d3a3' } ]
blockchain.lite (github: openblockchains/blockchain.lite.rb, gem: blockchainlite) - build your own blockchain with crypto hashes - revolutionize the world with blockchains, blockchains, blockchains one block at a time
require 'blockchainlite'
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 will pretty print (pp) something like:
[#<Block:0x1eed2a0
@index = 0,
@timestamp = 2017-09-15 20:52:38,
@data = "Genesis",
@previous_hash = "0",
@hash = "edbd4e11e69bc399a9ccd8faaea44fb27410fe8e3023bb9462450a0a9c4caa1b">,
#<Block:0x1eec9a0
@index = 1,
@timestamp = 2017-09-15 20:52:38,
@data = "Transaction Data...",
@hash = "eb8ecbf6d5870763ae246e37539d82e37052cb32f88bb8c59971f9978e437743",
@previous_hash = "edbd4e11e69bc399a9ccd8faaea44fb27410fe8e3023bb9462450a0a9c4caa1b">,
...
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
Learn Enough Git to Be Dangerous by Michael Hartl - FREE (Online Version) -- Getting started ++ Backing up and sharing ++ Intermediate workflow ++ Collaborating ++ Conclusion ++ Advanced setup
Pro Git by Scott Chacon and Ben Straub, 2nd Edition, 2014 - FREE (Online Version) -- Getting Started ++ Git Basics ++ Git Branching ++ Git on the Server ++ Distributed Git ++ GitHub ++ Git Tools ++ Customizing Git ++ Git and Other Systems ++ Git Internals ++ A1: Git in Other Environments ++ A2: Embedding Git in your Applications ++ A3: Git Commands
Git gets easier once you get the basic idea that branches are homeomorphic endofunctors mapping submanifolds of a Hilbert space. -- Anonymous
football.db - open public domain football datasets (incl. clubs, national teams, leagues, match schedules, etc.)
world.db - open public domain world (country) datasets
beer.db - open public domain beer & brewery datasets
Add a beer transaction to the #blockchain on #git and win a free Wiener Lager beer! Cheers. Prost. -- Gerald Bauer @ Vienna.html
Schilling - Schilling on the Blockchain! - Rock-Solid Alpine Dollar from Austria
A period in the Dutch Golden Age during which contract prices for bulbs of the recently introduced tulip reached extraordinarily high levels and then dramatically collapsed in February 1637.
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
Tulipomania: The Story of the World's Most Coveted Flower & the Extraordinary Passions It Aroused by Mike Dash, 2001 -- A Mania for Tulips ++ The Valley of Tien Shan ++ Within the Abode of Bliss ++ Stranger from the East ++ Clusius ++ Leiden ++ An Adornment to the Cleavage ++ The Tulip in the Mirror ++ Florists ++ Boom ++ At the Sign of the Golden Grape ++ The Orphans of Wouter Winkel ++ Bust ++ Goddess of Whores ++ At the Court of the Tulip King ++ Late Flowering
License
The awesome list is dedicated to the public domain. Use it as you please with no restrictions whatsoever.