Category: Blockchain

a = 128
print(a.to_bytes(2, 'big'))
print(a.to_bytes(4, 'big'))

print(int.from_bytes(b'\x00\x80', 'big'))
print(int.from_bytes(b'\x00\x00\x00\x80', 'big'))

import hashlib

class Block():
    def __init__(self, data, prev_hash):
        self.index = 0
        self.nonce = 0
        self.prev_hash = prev_hash
        self.data = data

    def blockhash(self):
        blockheader = str(self.index) + str(self.prev_hash) + str(self.data) + str(self.nonce)
        block_hash = hashlib.sha256(blockheader.encode()).hexdigest()
        return block_hash

    def __str__(self):
        return "Block Hash: " + self.blockhash() + "\nPrevious Hash: " + self.prev_hash + "\nindex: " + str(self.index) + "\nData: " + str(self.data) + "\nNonce: " + str(self.nonce) + "\n--------------"

class Hashchain():
    def __init__(self):
        self.chain = ["0000000000000000000000000000000000000000000000000000000000000000"]

    def add(self, hash):
        self.chain.append(hash)

hashchain = Hashchain()
target = 0x777777 * 2**(8*(0x1e - 0x03))

for i in range(30):
    block = Block("Block " + str(i+1), hashchain.chain[-1])
    block.index = block.index + i + 1
    for n in range(4294967296):
        block.nonce = block.nonce + n
        if int(block.blockhash(), 16) < target:
            print(block)
            hashchain.add(block.blockhash())
            break

簡易的なhash計算

import hashlib

input_text = "satoshi"

for nonce in range(20):
    input_data = input_text + str(nonce)
    hash = hashlib.sha256(input_data.encode("UTF-8")).hexdigest()
    print(input_data + " → " + hash)

ブロックヘッダのdifficulty bitsにハッシュ値の条件が書かれている
0x1e777777 のような形式で記述されている。

# difficulty_bits = 0x1e777777
# exponent = 0x1e
# coefficient = 0x777777

target = 0x777777 * 2**(8*(0x1e - 0x03))
print(target)

target_hex = hex(target)[2:].zfill(64)
print(target_hex)

import hashlib

class Block():
    def __init__(self, data, prev_hash):
        self.index = 0
        self.nonce = 0
        self.prev_hash = prev_hash
        self.data = data

    def blockhash(self):
        blockheader = str(self.index) + str(self.prev_hash) + str(self.data) + str(self.nonce)
        block_hash = hashlib.sha256(blockheader.encode()).hexdigest()
        return block_hash

    def __str__(self):
        return "Block Hash: " + self.blockhash() + "\nPrevious Hash: " + self.prev_hash + "\nindex: " + str(self.index) + "\nData: " + str(self.data) + "\nNonce: " + str(self.nonce) + "\n--------------"

class Hashchain():
    def __init__(self):
        self.chain = ["0000000000000000000000000000000000000000000000000000000000000000"]

    def add(self, hash):
        self.chain.append(hash)

hashchain = Hashchain()
target = 0x777777 * 2**(8*(0x1e - 0x03))

for i in range(30):
    block = Block("Block " + str(i+1), hashchain.chain[-1])
    block.index = block.index + i + 1
    for n in range(4294967296):
        block.nonce = block.nonce + n
        if int(block.blockhash(), 16) < target:
            print(block)
            hashchain.add(block.blockhash())
            break

import json
import requests

address = "3FkenCiXpSLqD8L79intRNXUgjRoH9sjXa"

res = requests.get("https://blockchain.info/unspent?active=" + address)
utxo_list = json.loads(res.text)["unspent_outputs"]

print(str(len(utxo_list)) + "個のutxoが見つかりました")
for utxo in utxo_list:
    print(utxo["tx_hash"] + ":" + str(utxo["value"]) + " satoshis")

blockcain exploreのtransactionからも確認できる。
https://www.blockchain.com/explorer

$ python3 utxo.py
2個のutxoが見つかりました
0aed6c01112af0a2dd51981e983ce41ef271c3bbec834121a47dbe31c30519d7:548546 satoshis
768b2e91eaa99208d32d3dde2a0f70214940584754b66378a33c9e3bd60136c3:311694 satoshis

import os
import binascii

private_key = os.urandom(32)
print(private_key)
print(binascii.hexlify(private_key))

32バイトの乱数を生成して、バイナリデータを16進数に変換

$ python3 wallet.py
b’W~\x9cj\xcc}\x0f1J\xab\xa6Hh\x87\xe7\xa6x2\xb1c,\xe9\x1dZp{R\xc3\x8e9-\xe2′
b’577e9c6acc7d0f314aaba6486887e7a67832b1632ce91d5a707b52c38e392de2′

公開鍵に楕円曲線暗号を使用します。
$ pip install ecdsa

import os
import ecdsa
import binascii

private_key = os.urandom(32)
public_key = ecdsa.SigningKey.from_string(private_key, curve=ecdsa.SECP256k1).verifying_key.to_string()

print(binascii.hexlify(private_key))
print(binascii.hexlify(public_key))

y^2 = x^3 + 7 mod p

import os
import ecdsa
import binascii

private_key = os.urandom(32)
public_key = ecdsa.SigningKey.from_string(private_key, curve=ecdsa.SECP256k1).verifying_key.to_string()

print(binascii.hexlify(private_key))
print(binascii.hexlify(public_key))

# public_key y-axis
public_key_y = int.from_bytes(public_key[32:], "big")

# create compressed public_key
if public_key_y % 2 == 0:
    public_key_compressed = b"\x02" + public_key[:32]
else:
    public_key_compressed = b"\x03" + public_key[:32]

print(binascii.hexlify(public_key_compressed))

### sakura vpsの契約
1GB メモリ、100ssdで契約する。1ヶ月990円。
OSはalma linuxをインストール

### メモリ増強
1GBでは足りないらしいので、メモリを増強する
$ sudo fallocate -l 8G /swapfile
$ sudo chmod 600 /swapfile
$ sudo mkswap /swapfile
Setting up swapspace version 1, size = 8 GiB (8589930496 bytes)
no label, UUID=6a1c4a72-0340-40f3-be3a-9b7245afc3f0
$ sudo swapon /swapfile
$ free
total used free shared buff/cache available
Mem: 985552 126696 506488 31216 352368 689008
Swap: 8388604 0 8388604

### ポート解放
パケットフィルターでTCPの8333ポートを解放する

### alma linuxにbitcoin coreをinstall
$ sudo dnf install epel-release
$ sudo dnf upgrade
$ sudo dnf install snapd
$ sudo systemctl enable –now snapd.socket
$ sudo ln -s /var/lib/snapd/snap /snap
$ sudo snap install bitcoin-core
2023-10-31T08:08:07+09:00 INFO Waiting for automatic snapd restart…
bitcoin-core 25.1 from Bitcoin Core installed

### bit coin
$ bitcoin-core.cli –version
Bitcoin Core RPC client version v25.1.0
Copyright (C) 2009-2023 The Bitcoin Core developers

Please contribute if you find Bitcoin Core useful. Visit
for further information about the software.
The source code is available from .

This is experimental software.
Distributed under the MIT software license, see the accompanying file COPYING
or

$ snap info bitcoin-core
name: bitcoin-core
summary: Fully validating Bitcoin peer-to-peer network node, wallet and GUI
publisher: Bitcoin Core
store-url: https://snapcraft.io/bitcoin-core
contact: https://github.com/bitcoin-core/packaging/issues/new?title=snap:
license: unset
description: |
Bitcoin Core connects to the Bitcoin peer-to-peer network to download and
fully validate blocks and transactions. It also includes a wallet and
graphical user interface.
commands:
– bitcoin-core.cli
– bitcoin-core.daemon
– bitcoin-core.qt
– bitcoin-core.tx
– bitcoin-core.util
– bitcoin-core.wallet

$ bitcoin-core.cli -getinfo
error: timeout on transient error: Could not connect to the server 127.0.0.1:8332

Make sure the bitcoind server is running and that you are connecting to the correct RPC port.

### 再起動
VPS再起動

$ bitcoin-core.daemon -testnet

snapでinstallすると、実行コマンドが違うので注意が必要

こちらの記事を参考に動かしてみる
https://alis.to/gaxiiiiiiiiiiii/articles/3dy7vLZn0g89

トランザクションのハッシュ値作成の箇所は、Node(left.hash + right.hash)として、hash値を単純に横に繋げてそれをsha256でハッシュ化してるところが面白い。

from hashlib import sha256

class Node:
    def __init__(self, data):
        self.left     = None
        self.right    = None
        self.parent   = None
        self.sibling  = None
        self.position = None
        self.data     = data
        self.hash = sha256(data.encode()).hexdigest()
       
class Tree:
    def __init__(self, leaves):
        self.leaves = [Node(leaf) for leaf in leaves]
        self.layer  = self.leaves[::]
        self.root   = None
        self.build_tree()
    
    def build_layer(self):
        new_layer = []
        
        if len(self.layer) % 2 == 1:
            self.layer.append(self.layer[-1])
        
        for i in range(0, len(self.layer), 2):
            left = self.layer[i]
            right = self.layer[i+1]
            parent = Node(left.hash + right.hash)
            
            left.parent = parent
            left.sibling = right
            left.position = "left"
            
            right.parent = parent
            right.sibling = left
            right.position = "right"
            
            parent.left = left
            parent.right = right
            
            new_layer.append(parent)
        
        self.layer = new_layer
    
    def build_tree(self):
        while len(self.layer) > 1:
            self.build_layer()
        self.root = self.layer[0].hash
    
    def search(self, data):
        target = None
        hash_value = sha256(data.encode()).hexdigest()
        for node in self.leaves:
            if node.hash == hash_value:
                target = node
        return target
    
    def get_pass(self, data):
        target = self.search(data)
        markle_pass = []
        if not(target):
            return
        markle_pass.append(target.hash)
        while target.parent:
            sibling = target.sibling
            markle_pass.append((sibling.hash, sibling.position))
            target = target.parent
        return markle_pass   
      
def caluculator(markle_pass):
    value = markle_pass[0]
    for node in markle_pass[1:]:
        sib = node[0]
        position = node[1]
        if position == "right":
            value = sha256(value.encode() + sib.encode()).hexdigest()
        else:
            value = sha256(sib.encode() + value.encode()).hexdigest()
    return value  

マークルツリーでsha256のハッシュ計算を行う際に、単純にハッシュ値をつなぎ合わせて、それをさらにsha256で計算しているようだ。
トランザクション1とトランザクション2からのハッシュ値は何度実行しても同じになる。

import hashlib

tx1 = 'abc'
tx2 = 'cde'

tx1hash = hashlib.sha256(tx1.encode()).hexdigest()
print(tx1hash)
tx2hash = hashlib.sha256(tx2.encode()).hexdigest()
print(tx2hash)
tx12 = tx1hash + tx2hash
tx12hash = hashlib.sha256(tx12.encode()).hexdigest()
print(tx12hash)

$ python3 test.py
ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad
08a018a9549220d707e11c5c4fe94d8dd60825f010e71efaa91e5e784f364d7b
e7ea6d8ded8ff13bb4e3fccadb13878004f69bad2d3d9d33f071c13a650303ba

names = ["Alice", "Bob", "Charlie"]

newData = [name + "さん" for name in names]
print(newData)

$ python3 test.py
[‘Aliceさん’, ‘Bobさん’, ‘Charlieさん’]

リストで返すようにすれば1行で書ける

pythonでの関数の呼び出し

def some_function(something):
	print(something)

some_function("hello world")

Classにした場合
L インスタンスを生成して処理を実行する
　　L クラスの中の関数をメソッドと呼ぶ

class SomeClass:
	def __init__(self, something):
		self.something = something

	def some_function(self):
		print(self.something)


c = SomeClass("hello world")
c.some_function()

class SomeClass:
	def __init__(self, something):
		self.something = something

	def some_function(self):
		print(self.something)

	def some_function2(self):
		return self.something


c = SomeClass("hello world")
c.some_function()
print(c.some_function2())

selfはインスタンス自身のこと
initはデータの初期化の関数

class MyStatus:
	def __init__(self, age, name, height, weight):
		self.age = age
		self.name = name
		self.height = height
		self.weight = weight

	def print_name(self):
		print(self.name)

	def print_age(self):
		print(self.age)

	def print_height(self):
		print(self.height)

	def print_weight(self):
		print(self.weight)

a = MyStatus(14, "yamada", 160, 55)
a.print_height()	 

コーヒーメーカーのClassを作ってみる

class CoffeeMaker:
	def __init__(self, water, brand, tempreture):
		self.water = water # mill
		self.brand = brand
		self.tempreture = tempreture

	def boiling(self):
		boilingTime = self.water / 10 * self.tempreture
		print(boilingTime)

	def brew(self):
		print(self.brand + "を滴れました")

a = CoffeeMaker(300, "brend", 3)
a.boiling()	
a.brew() 

$ python3 test.py
90.0
brendを滴れました

なるほど、Classと関数とinitの使い方について、自分で例を作ると構造を理解できますね。

phpの場合はinitのところが__contructになります。引数はconstructで定義しています。

class Dog {
private $name;

public function __construct($name) {
$this->name = $name;
}

public function getName(){
echo $this->name;
}
}

$dog = new Dog(“Pochi”);

$dog->getName();
[/code]

ini_set('display_errors', "On");

class CoffeeShop {
	private $order;
	private $pay;

	public function __construct($order, $pay) {
		$this->order = $order;
		$this->pay = $pay;
	}

	public function coffeePrice(){
		switch ($this->order) {
			case "ブレンド":
				echo "price is 330 yen\n";
				$price = 330;
				break;
			case "アメリカン":
				echo "price is 350 yen\n";
				$price = 350;
				break;
			case "アイスコーヒー":
				echo "price is 380 yen\n";
				$price = 380;
				break;
			default:
				echo "not available at this store";
		}

		$change = $this->pay - $price;
		return $change;
	}

	
}

$a = new CoffeeShop("ブレンド", 1000);
$b = $a->coffeePrice();
echo $b;