Day 2 - blockchain-lite Gem - Build Your Own Blockchains with Crypto Hashes. Revolutionize the World one Block at a Time!
Written by {% avatar geraldb %} Gerald Bauer
A code monkey formerly at Big Korupto. Jobless no coiner having fun staying poor and wrong. Writing the Get Rich Quick "Business Blockchain" Bible - The Secrets of Free Easy Money.
A blockchain is a list (that is, chain) of records (that is, blocks) linked and secured by digital fingerprints (that is, crypto hashes).
See the Awesome Blockchains page for more.
Build your own blockchain one block at a time. Example:
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 blockchainwill pretty print (pp) something like:
[#<Block:0x1eed2a0
@index = 0,
@timestamp = 2021-01-04 20:52:38,
@data = "Genesis",
@previous_hash = "0",
@hash ="edbd4e11e69bc399a9ccd8faaea44fb27410fe8e3023bb9462450a0a9c4caa1b">,
#<Block:0x1eec9a0
@index = 1,
@timestamp = 2021-01-04 20:52:38,
@data = "Transaction Data...",
@hash = "eb8ecbf6d5870763ae246e37539d82e37052cb32f88bb8c59971f9978e437743",
@previous_hash = "edbd4e11e69bc399a9ccd8faaea44fb27410fe8e3023bb9462450a0a9c4caa1b">,
#<Block:0x1eec838
@index = 2,
@timestamp = 2021-01-04 20:52:38,
@data = "Transaction Data......",
@hash = "be50017ee4bbcb33844b3dc2b7c4e476d46569b5df5762d14ceba9355f0a85f4",
@previous_hash = "eb8ecbf6d5870763ae246e37539d82e37052cb32f88bb8c59971f9978e437743">,
#<Block:0x1eec6d0
@index = 3,
@timestamp = 2021-01-04 20:52:38
@data = "More Transaction Data...",
@hash = "5ee2981606328abfe0c3b1171440f0df746c1e1f8b3b56c351727f7da7ae5d8d",
@previous_hash = "be50017ee4bbcb33844b3dc2b7c4e476d46569b5df5762d14ceba9355f0a85f4">]
Supported block types / classes for now include basic and proof-of-work.
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.utc ## note: use coordinated universal time (utc)
@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
...
endComments 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.
class Block
attr_reader :index
attr_reader :timestamp
attr_reader :data
attr_reader :previous_hash
attr_reader :nonce ## proof of work if hash starts with leading zeros (00)
attr_reader :hash
def initialize(index, data, previous_hash)
@index = index
@timestamp = Time.now.utc ## note: use coordinated universal time (utc)
@data = data
@previous_hash = previous_hash
@nonce, @hash = compute_hash_with_proof_of_work
end
...
endLet'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 (^1,2). Three leading zeros (000) would be 16^3 = 4_096 possibilites and four zeros (0000) would be 16^4 = 65_536 and so on.
(^1): 16 possibilties because it's a hex or hexadecimal or base 16 number, that is, 0 1 2 3 4 6 7 8 9 a (10) b (11) c (12) d (13) e (14) f (15).
(^2): A random secure hash algorithm needs on average 256 tries (might be lets say 305 tries, for example, because it's NOT a perfect statistic distribution of possibilities).
Example:
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
endLet'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">,
#<Block:0x1fa8338
@index = 3,
@timestamp = 1637-09-20 20:43:38,
@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.
The bitcoin code is archaic and out-of-date. Burn, baby, burn! Proof-of-waste is a global energy environmental disaster using 300 kWh per bitcoin transaction (!) that's about 179 kilograms of CO₂ emissions.
To the moon!? The new gold standard!? Programmable money (or the internet of value) for all future generations with (bitcoin) script without loops and jumps (gotos) and all "stateless"!? LOL.
BEWARE: Bitcoin is a gigantic ponzi scheme. Do NOT "invest" trying to get-rich-quick HODLing.
Let's put the transactions from the (hyper) ledger book from Tulips on the Blockchain! on the blockchain:
| 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 |
(†): Grower Transaction - New Tulips on the Market!
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
@index = 0,
@timestamp = 1637-09-24 11:40:15,
@previous_hash = "0",
@hash = "32bd169baebba0b70491b748329ab631c85175be15e1672f924ca174f628cb66",
@transactions_count = 2,
@transactions =
[{:from=>"Dutchgrown", :to=>"Vincent", :what=>"Tulip Bloemendaal Sunset", :qty=>10},
{:from=>"Keukenhof", :to=>"Anne", :what=>"Tulip Semper Augustus", :qty=>7}]>,
#<Block:0x2da2ff0
@index = 1,
@timestamp = 1637-09-24 11:50:15,
@previous_hash = "32bd169baebba0b70491b748329ab631c85175be15e1672f924ca174f628cb66",
@hash = "57b519a8903e45348ac8a739c788815e2bd90423663957f87e276307f77f1028",
@transactions_count = 4,
@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}]>,
#<Block:0x2da2720
@index = 2,
@timestamp = 1637-09-24 12:00:15,
@previous_hash = "57b519a8903e45348ac8a739c788815e2bd90423663957f87e276307f77f1028",
@hash = "ec7dd5ea86ab966d4d4db182abb7aa93c7e5f63857476e6301e7e38cebf36568",
@transactions_count = 4,
@transactions =
[{: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}]>,
...
That's it. Now revolutionize the world with blockchains one block at a time.
- Home :: github.com/rubycoco/blockchain/blockchain.lite
- Gem :: blockchain-lite
- Docs :: blockchain-lite
- Article :: Programming Blockchains Step-by-Step from Scratch. Starting with Crypto Hashes...
- Books :: Best of Crypto Books