Blockchain Explained - Example of creating a Blockchain using Python

Example of creating a Blockchain using Python.py

import hashlib
import datetime as dt

# Define a block class
class block:
   def __init__(self, time, data, prev_hash):
       self.timestamp = time
       self.data = data
       self.prev_hash = prev_hash
       self.hashvalue = self.generate_hash()
   def generate_hash(self):
       data = str(self.timestamp) + str(self.data) + str(self.prev_hash)
       hashvalue = hashlib.sha256(data.encode()).hexdigest()
       return hashvalue

# Create the genesis block with previous hash value as 0
def create_genesis_block():
   timestamp = dt.datetime.now()
   data = 'Genesis block'
   prev_hash = '0'
   return block(time=timestamp, data=data, prev_hash=prev_hash)

# Generate all later blocks in the blockchain
def create_block(prev_block, sender, receiver, amount):
    timestamp = dt.datetime.now()
    data = f'Sender: {sender}\nReceiver: {receiver}\nAmount: {amount}'
    print('Data for this block is:\n',data)
    prev_hash = prev_block.hashvalue
    return block(time=timestamp, data=data, prev_hash=prev_hash)

# Let's create a simple blockchain with the genesis block
our_first_blockchain = [create_genesis_block()]

# The genesis block will be the previous block for the next block of the blockchain
prev_block = our_first_blockchain[0]

# Let us create a blockchain with 10 blocks
num_blocks = 10
for i in range(1, num_blocks+1):
   next_block = create_block(prev_block, sender='Sender'+str(i), receiver='Receiver'+str(i), amount=i*1000)
   our_first_blockchain.append(next_block)
   print(f'Block number {i} is added to the blockchain. \nIts hash is {next_block.hashvalue}.\nHash of previous block is {next_block.prev_hash}.\n\n')
   prev_block = next_block