init project

.gitignore

@@ -0,0 +1,184 @@
+### VirtualEnv template
+# Virtualenv
+# http://iamzed.com/2009/05/07/a-primer-on-virtualenv/
+.Python
+[Bb]in
+[Ii]nclude
+[Ll]ib
+[Ll]ib64
+[Ll]ocal
+[Ss]cripts
+pyvenv.cfg
+.venv
+pip-selfcheck.json
+
+### Example user template template
+### Example user template
+
+# IntelliJ project files
+.idea
+*.iml
+out
+gen
+### Python template
+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+share/python-wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.nox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+*.py,cover
+.hypothesis/
+.pytest_cache/
+cover/
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+db.sqlite3-journal
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+.pybuilder/
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pyenv
+#   For a library or package, you might want to ignore these files since the code is
+#   intended to run in multiple environments; otherwise, check them in:
+# .python-version
+
+# pipenv
+#   According to pypa/pipenv#598, it is recommended to include Pipfile.lock in version control.
+#   However, in case of collaboration, if having platform-specific dependencies or dependencies
+#   having no cross-platform support, pipenv may install dependencies that don't work, or not
+#   install all needed dependencies.
+#Pipfile.lock
+
+# poetry
+#   Similar to Pipfile.lock, it is generally recommended to include poetry.lock in version control.
+#   This is especially recommended for binary packages to ensure reproducibility, and is more
+#   commonly ignored for libraries.
+#   https://python-poetry.org/docs/basic-usage/#commit-your-poetrylock-file-to-version-control
+#poetry.lock
+
+# pdm
+#   Similar to Pipfile.lock, it is generally recommended to include pdm.lock in version control.
+#pdm.lock
+#   pdm stores project-wide configurations in .pdm.toml, but it is recommended to not include it
+#   in version control.
+#   https://pdm.fming.dev/#use-with-ide
+.pdm.toml
+
+# PEP 582; used by e.g. github.com/David-OConnor/pyflow and github.com/pdm-project/pdm
+__pypackages__/
+
+# Celery stuff
+celerybeat-schedule
+celerybeat.pid
+
+# SageMath parsed files
+*.sage.py
+
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+
+# Spyder project settings
+.spyderproject
+.spyproject
+
+# Rope project settings
+.ropeproject
+
+# mkdocs documentation
+/site
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
+
+# Pyre type checker
+.pyre/
+
+# pytype static type analyzer
+.pytype/
+
+# Cython debug symbols
+cython_debug/
+
+# PyCharm
+#  JetBrains specific template is maintained in a separate JetBrains.gitignore that can
+#  be found at https://github.com/github/gitignore/blob/main/Global/JetBrains.gitignore
+#  and can be added to the global gitignore or merged into this file.  For a more nuclear
+#  option (not recommended) you can uncomment the following to ignore the entire idea folder.
+#.idea/
+

README.md

@@ -0,0 +1,130 @@
+## 1. 区块链技术的核心概念和原理
+- 密码朋克 (Cypher punk)
+  - 维基解密的创始人 阿桑奇
+  - BT下载的作者 布莱姆-科恩
+  - WWW 的发明者 蒂姆博纳斯-李
+  - 智能合约概念的提出者: 尼克萨博
+  - Facebook 创始人： 肖恩帕克
+  - 中本聪
+
+- Adam Back 发明了 Hash cash, 使用了 POW
+- Haber/ Stornetta 提出时间戳方法保证数字文件安全的协议
+- 戴维 发明了 B-money, 强调了点对点交易和不可更改记录
+- 哈尔-芬尼 推出了 "加密现金"
+- 2008 年中本聪 《比特币: 一个点对点的电子现金系统》
+
+- 区块链技术前景
+  - 应用场景 
+    - 资产：数字资产发行, 支付(跨境支付), 交易, 结算
+    - 记账：股权交易, 供应链金融, 商业积分
+    - 不可篡改：溯源, 众筹, 医疗证明, 存在性证明
+    - 点对点：共享经济, 物联网
+    - 隐私： 匿名交易
+
+- 什么是货币？
+  - 凯恩斯《货币论》货币是可以承载价值的一般等价物
+
+- 货币历史
+  - 铜币, 金银 -> 银票 -> 法币 -> 数字货币(一串数字)
+
+- 信任从何而来
+  - 财产只受自己控制
+  - 无通胀(总量不变得)
+  - 没有假钞
+  - 流通性好
+
+- 比特币是什么
+  - 去中心化的记账系统
+
+- 比特币的原理
+  - 账本如何验证？
+  - 所有权问题?
+  - 为什么记账?（挖矿）
+  - 以谁的账本为准?(共识机制)
+
+- Hash
+  - 哈希函数: Hash(原始信息) = 摘要信息
+  - 特点：
+    - 同样的原始信息用同一个哈希函数总能得到相同的摘要信息
+    - 原始信息任何微小的变化都会哈希出面目全非的摘要信息
+    - 从摘要信息无法逆向推算出原始信息
+
+- 非对称加密技术（交易签名）
+  - 交易进行hash得到摘要
+  - 用私钥对摘要进行签名
+
+- 所有权问题? 广播交易
+  - 签名及验证
+
+- 为什么记账？
+  - 记账： Hash 打包过程
+  - 消耗资源
+  - 奖励 -> 比特币发行
+
+- 挖矿 - 工作量证明
+  - 规则: 一段时间内只有一人可以记账成功
+  - 通过解决密码学的难题(即工作量证明)竞争获得唯一记账权
+  - 其他的节点复制记账结果
+
+- 工作量证明
+  - Hash(上一个Hash值, 交易记录集) = 456635BCD
+  - Hash(上一个Hash值, 交易记录集, 随机数) = 0000aFD635BCD
+  
+- 交易记录集
+  - 收集广播中还没有被记录账本的交易
+  - 交易的有效性验证
+  - 添加一笔给自己转账的交易(挖矿奖励)
+
+- 共识机制
+  - 两个节点同时完成工作量证明, 使用谁的区块?
+    - 无仲裁机构裁决
+  - 为什么要遵守协议?
+    - 节点的工作量只有在其他节点认可认同其是有效地
+    - 累计工作量最大的区块链
+      - 独立
+      - 延长最长链
+
+## 2. 区块链的原理实现 (Python3)
+
+- python, pip, pipenv, Flask/requests
+
+```shell
+# 安装运行的环境
+pip install pipenv
+# 安装 python 的运行环境 -> 生成 Pipfile
+pipenv --python=python3.6
+# 安装需要的依赖
+pipenv install flask==0.12.2
+pipenv install requests==2.18.4
+```
+
+### 2.1 创建项目及区块结构
+- blockchain.py
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+##

demo/blockchain.py

@@ -0,0 +1,279 @@
+# -*- coding: utf-8 -*-
+import hashlib
+import json
+from argparse import ArgumentParser
+from time import time
+from urllib.parse import urlparse
+from uuid import uuid4
+
+import requests
+from flask import Flask, jsonify, request
+
+
+# 区块的结构
+# {
+#     # 序号
+#     "index": 0,
+#     # 时间戳
+#     "timestamp": "",
+#     # 交易信息
+#     "transactions": [
+#         {
+#             # 交易的发送者
+#             "sender": "",
+#             # 交易的接收者
+#             "recipient": "",
+#             # 交易的金额
+#             "amount": 5
+#         }
+#
+#     ],
+#     # 工作量证明
+#     "proof": "",
+#     # 上一个区块的 Hash值
+#     "previous_hash": ""
+# }
+
+class Blockchain:
+
+    # 初始化
+    def __init__(self):
+        self.chain = []
+        self.current_transactions = []
+        #  保存节点的信息
+        self.nodes = set()
+
+        # 创建一个创世纪的区块定义
+        self.new_block(proof=100, previous_hash=1)
+
+    # 验证链为有效链 -> Hash值和工作量证明是否有效
+    def valid_chain(self, chain) -> bool:
+        last_block = chain[0]
+        current_index = 1
+
+        while current_index < len(chain):
+            block = chain[current_index]
+
+            # Hash 不一致, 则校验不通过, 是虚假的信息
+            if block['previous_hash'] != self.hash(last_block):
+                return False
+
+            # 工作量证明可能不满足, 不满足 "0000"开头的
+            if not self.valid_proof(last_block['proof'], block['proof']):
+                return False
+
+            last_block = block
+            current_index += 1
+        return True
+
+    # 共识机制 解决多个节点的冲突问题
+    def resolve_conflicts(self) -> bool:
+        # 使用当前链的长度和附近节点的链的长度进行对比, 选择最长的链进行继续工作
+        neighbours = self.nodes
+        max_length = len(self.chain)
+        new_chain = None
+
+        for node in neighbours:
+            response = requests.get(f'http://{node}/chain')
+            if response.status_code == 200:
+                length = response.json()['length']
+                chain = response.json()['chain']
+
+                if length > max_length and self.valid_chain(chain):
+                    max_length = length
+                    new_chain = chain
+        if new_chain:
+            self.chain = new_chain
+            return True
+
+        return False
+
+    # 注册一个节点
+    def register_node(self, address: str):
+        # 解析节点信息 127.0.0.1:5001, 保存到 nodes 里面
+        parsed_url = urlparse(address)
+        self.nodes.add(parsed_url.netloc)
+
+    # 创建新的区块
+    def new_block(self, proof, previous_hash=None):
+        # 创建区块, 把交易信息加入区块
+        block = {
+            'index': len(self.chain) + 1,
+            'timestamp': time(),
+            'transactions': self.current_transactions,
+            'proof': proof,
+            'previous_hash': previous_hash or self.hash(self.last_block)
+        }
+
+        #  把交易信息清空
+        self.current_transactions = []
+        # 把区块加入到链中
+        self.chain.append(block)
+
+        return block
+
+    # 新添加一个交易
+    def new_transaction(self, sender, recipient, amount) -> int:
+        # 把创建的交易信息作为一个交易记录[json], 放在交易列表里
+        self.current_transactions.append(
+            {
+                'sender': sender,
+                'recipient': recipient,
+                'amount': amount
+            }
+        )
+
+        # 返回区块的索引
+        return self.last_block['index'] + 1
+
+    #  (静态) 计算 Hash
+    @staticmethod
+    def hash(block):
+        # json 排序转成 字符串, 然后进行编码
+        block_str = json.dumps(block, sort_keys=True).encode()
+
+        # 使用 hash 函数进行 hash, 并返回摘要信息
+        return hashlib.sha256(block_str).hexdigest()
+
+    # (属性) 获取最后一个区块
+    @property
+    def last_block(self):
+        return self.chain[-1]
+
+    # 工作量证明
+    def proof_of_work(self, last_proof: int) -> int:
+        proof = 0
+        while self.valid_proof(last_proof, proof) is False:
+            proof += 1
+
+        # print(proof)
+        return proof
+
+    # 验证合规的工作量 比如以几个 0 开头, 这里先定义 4个0
+    @staticmethod
+    def valid_proof(last_proof: int, proof: int) -> bool:
+        # 字符串拼接并进行编码 -> 构建 guess
+        guess = f'{last_proof}{proof}'.encode()
+        # 获取 guess 的 hash 值
+        guess_hash = hashlib.sha256(guess).hexdigest()
+        # print(guess_hash)
+
+        return guess_hash[0:4] == "0000"
+
+
+app = Flask(__name__)
+block_chain = Blockchain()
+
+# UUID 来声明当前节点的ID
+node_identifier = str(uuid4()).replace('-', '')
+
+
+# 交易接口
+@app.route('/transactions/new', methods=['POST'])
+def new_transaction():
+    # 拿到请求内容
+    values = request.get_json()
+
+    # 检查请求字段是否完整
+    required = ["sender", "recipient", "amount"]
+    if values is None:
+        return "Missing values", 400
+    if not all(k in values for k in required):
+        return "Missing values", 400
+
+    index = block_chain.new_transaction(values['sender'], values['recipient'], values['amount'])
+
+    response = {"message": f'Transcation will be added to Block {index}'}
+    return jsonify(response), 201
+
+
+# 挖矿接口
+@app.route('/mine', methods=['GET'])
+def mine():
+    # 传入上一个工作量证明, 来计算当前的工作量证明
+    last_block = block_chain.last_block
+    last_proof = last_block['proof']
+    proof = block_chain.proof_of_work(last_proof)
+
+    # 新添加一个交易, 这个交易就是给自己的奖励
+    block_chain.new_transaction(sender="0", recipient=node_identifier, amount=1)
+
+    # 新建一个区块
+    block = block_chain.new_block(proof, None)
+
+    # 封装返回信息
+    response = {
+        "message": "New Block Forged",
+        "index": block['index'],
+        "transactions": block['transactions'],
+        "proof": block['proof'],
+        "previous_hash": block['previous_hash']
+    }
+    return jsonify(response), 200
+
+
+# 返回整个区块链信息
+@app.route('/chain', methods=['GET'])
+def full_chain():
+    response = {
+        'chain': block_chain.chain,
+        'length': len(block_chain.chain)
+    }
+    return jsonify(response), 200
+
+
+# 添加一个节点
+@app.route('/nodes/register', methods=['POST'])
+def register_nodes():
+    #  获取节点信息
+    values = request.get_json()
+    nodes = values.get("nodes")
+
+    if nodes is None:
+        return "Error: please supply a valid list of nodes", 400
+
+    for node in nodes:
+        block_chain.register_node(node)
+
+    response = {
+        "message": "New nodes have bean added",
+        "total_nodes": list(block_chain.nodes)
+    }
+
+    return jsonify(response), 201
+
+
+# 共识机制, 解决冲突的接口
+@app.route('/nodes/resolve', methods=['GET'])
+def consensus():
+    replaced = block_chain.resolve_conflicts()
+
+    if replaced:
+        response = {
+            'message': 'Our chain was replaced',
+            'new_chain': block_chain.chain
+        }
+    else:
+        response = {
+            'message': 'Our chain is authoritative',
+            'chain': block_chain.chain
+        }
+    return jsonify(response), 200
+
+
+if __name__ == '__main__':
+    # 测试一下 工作量证明
+    # test_Pow = Blockchain()
+    # test_Pow.proof_of_work(100)
+
+    # 单机模式
+    # app.run(host='0.0.0.0', port=5000)
+
+    # 多节点模式 , 通过命令行参数进行实现
+    # -p -port
+    parser = ArgumentParser()
+    parser.add_argument('-p', '-port', default=5000, type=int, help='port to listen to')
+    args = parser.parse_args()
+    port = args.port
+
+    app.run(host='0.0.0.0', port=port)