created base structure of the blockchain with directory structure, generating genesis block and adding new block with rule based blockhash

Author: tas-indranil

.gitignore

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+blockchain_project
+test.txt
+.idea
+**/__pycache__/

Blockchain/Backend/core/block.py

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+class Block:
+    """
+    Block is a storage container that stores transactions
+    """
+    def __init__(self, Height, Blocksize, BlockHeader, TxCount, Txs):
+        self.Height = Height
+        self.Blocksize = Blocksize
+        self.BlockHeader = BlockHeader
+        self.TxCount = TxCount
+        self.Txs = Txs

Blockchain/Backend/core/blockchain.py

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+import sys
+import time
+import json
+
+sys.path.append('D:/xampp/htdocs/sand_box/get_job/custom-python-blockchain')
+
+from Blockchain.Backend.core.block import Block
+from Blockchain.Backend.core.blockheader import BlockHeader
+from Blockchain.Backend.util.util import hash256
+
+ZERO_HASH = '0' * 64
+VERSION = 1
+
+
+class Blockchain:
+    def __init__(self):
+        self.chain = []
+        self.GenesisBlock()
+
+    def GenesisBlock(self):
+        BlockHeight = 0
+        prevBlockHash = ZERO_HASH
+        self.addBlock(BlockHeight, prevBlockHash)
+
+    def addBlock(self, BlockHeight, prevBlockHash):
+        timestamp = int(time.time())
+        Transaction = f"Code Architect sent {BlockHeight} Bitcoins to Indranil"
+        merkleRoot = hash256(Transaction.encode()).hex()
+        bits = 'ffff001f'
+        blockheader = BlockHeader(version=VERSION, prevBlockHash=prevBlockHash, merkleRoot=merkleRoot,
+                                  timestamp=timestamp, bits=bits)
+        blockheader.mine()
+        self.chain.append(Block(BlockHeight, 1, blockheader.__dict__, 1, Transaction).__dict__)
+        print(json.dumps(self.chain, indent=4))
+
+    def main(self):
+        while True:
+            lastBlock = self.chain[::-1]
+            BlockHeight = lastBlock[0]["Height"] + 1
+            prevBlockHash = lastBlock[0]["BlockHeader"]["blockHash"]
+            self.addBlock(BlockHeight, prevBlockHash)
+
+
+if __name__ == "__main__":
+    blockchain = Blockchain()
+    blockchain.main()

Blockchain/Backend/core/blockheader.py

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+from Blockchain.Backend.util.util import hash256
+
+
+class BlockHeader:
+    def __init__(self, version, prevBlockHash, merkleRoot, timestamp, bits):
+        self.bits = bits
+        self.timestamp = timestamp
+        self.merkleRoot = merkleRoot
+        self.prevBlockHash = prevBlockHash
+        self.version = version
+        self.nonce = 0
+        self.blockHash = ''
+
+    def mine(self):
+        while (self.blockHash[0:4]) != '0000':
+            self.blockHash = hash256((str(self.version) + self.prevBlockHash + self.merkleRoot + str(self.timestamp) + self.bits + str(self.nonce)).encode()).hex()
+            self.nonce += 1
+            print(f"Mining started {self.nonce}", end='\r')

Blockchain/Backend/util/__init__.py

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+import hashlib
+
+
+def hash256(s):
+    """Two rounds of SHA256"""
+    return hashlib.sha256(hashlib.sha256(s).digest()).digest()

Blockchain/Backend/util/util.py

@@ -1 +1,10 @@
-"# custom-python-blockchain" 
+# Custom Python Blockchain
+
+
+1. Let's create the directory structure first Root folder `Blockchain`, under that `Backend`, `Frontend` and `client`. 
+Under Backend, `core` and `util`. 
+2. Inside cre create a file name `block.py` and create a class name `Block`. Inside `__init__` method talke ` 
+Height, Blocksize, BlockHeader, TxCount, Txs` variables
+3. Create a new module `blockheader.py`, create a class call `BlockHeader`. Inside the `__init__` method will take 
+`version, prevBlockHash, merkleRoot, timestamp, bits` and declare `self.nonce = 0 , self.blockHash = ''`
+4. Create a 

README.md

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+certifi
+charset-normalizer
+click
+colorama
+Flask
+Flask-QRcode
+idna
+itsdangerous
+Jinja2
+MarkupSafe
+Pillow
+pycryptodome
+qrcode
+requests
+urllib3
+Werkzeug

requirements.txt

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+[
+    {
+        "Height": 0,
+        "Blocksize": 1,
+        "BlockHeader": {
+            "bits": "ffff001f",
+            "timestamp": 1692624756,
+            "merkleRoot": "01d3c8ffac385f49854b12bc69248645efddb80a0435dd09631643bdc605d1d1",
+            "prevBlockHash": "0000000000000000000000000000000000000000000000000000000000000000",
+            "version": 1,
+            "nonce": 52879,
+            "blockHash": "00001037bff589288c44d4294b840b974b6f412d321c8aab3886ea61a9d2ddd1"
+        },
+        "TxCount": 1,
+        "Txs": "Code Architect sent 0 Bitcoins to Indranil"
+    },
+    {
+        "Height": 1,
+        "Blocksize": 1,
+        "BlockHeader": {
+            "bits": "ffff001f",
+            "timestamp": 1692624771,
+            "merkleRoot": "ede8645e1159205c35365fc6b765fbea7acab3d30d83f2094e87b1dc2829b69b",
+            "prevBlockHash": "00001037bff589288c44d4294b840b974b6f412d321c8aab3886ea61a9d2ddd1",
+            "version": 1,
+            "nonce": 29018,
+            "blockHash": "00003fde2fa0db36931e389f003c7b73c023ab7b764ad0787fa601c8b02e9ab0"
+        },
+        "TxCount": 1,
+        "Txs": "Code Architect sent 1 Bitcoins to Indranil"
+    },
+    {
+        "Height": 2,
+        "Blocksize": 1,
+        "BlockHeader": {
+            "bits": "ffff001f",
+            "timestamp": 1692624778,
+            "merkleRoot": "ee3d44bff24ade0bd29fbf90bcfa1a8a2ef2c991a92bf92e8e8d7bf85cf75e30",
+            "prevBlockHash": "00003fde2fa0db36931e389f003c7b73c023ab7b764ad0787fa601c8b02e9ab0",
+            "version": 1,
+            "nonce": 27230,
+            "blockHash": "00005ad8ab369e6c399cbbf13170ecb403e4d103f3d7c3f1bce28946e672fb23"
+        },
+        "TxCount": 1,
+        "Txs": "Code Architect sent 2 Bitcoins to Indranil"
+    },
+    {
+        "Height": 3,
+        "Blocksize": 1,
+        "BlockHeader": {
+            "bits": "ffff001f",
+            "timestamp": 1692624784,
+            "merkleRoot": "d0249e654794fa76a823925895732057dc5c51075131f4784a65d31f93754113",
+            "prevBlockHash": "00005ad8ab369e6c399cbbf13170ecb403e4d103f3d7c3f1bce28946e672fb23",
+            "version": 1,
+            "nonce": 89050,
+            "blockHash": "0000a4906e8daed09d5ad654ec4d6d119a060483b7f91e0f931cb68c98e28d88"
+        },
+        "TxCount": 1,
+        "Txs": "Code Architect sent 3 Bitcoins to Indranil"
+    }
+]