blockchain_de_prueba.py

import hashlib as hasher
import datetime as date

# Define la estructura del bloque
class Block:
  def __init__(self, index, timestamp, data, previous_hash):
    self.index = index
    self.timestamp = timestamp
    self.data = data
    self.previous_hash = previous_hash
    self.hash = self.hash_block()
  
  def hash_block(self):
    sha = hasher.sha256()
    sha.update(str(self.index) + str(self.timestamp) + str(self.data) + str(self.previous_hash))
    return sha.hexdigest()

# Genera el bloq inicial o genesis
def create_genesis_block():
  # Manualmente construimos un bloque
  # con el indice cero y con un hash vacio
  return Block(0, date.datetime.now(), "Genesis Block", "0")

# Genera los siguientes bloques
def next_block(last_block):
  this_index = last_block.index + 1
  this_timestamp = date.datetime.now()
  this_data = "Hey! I'm block " + str(this_index)
  this_hash = last_block.hash
  return Block(this_index, this_timestamp, this_data, this_hash)

# Crea los bloques así como el bloq inicial
blockchain = [create_genesis_block()]
previous_block = blockchain[0]

# Especificamos el numero de bloq a armar
# despues del block genesis
num_of_blocks_to_add = 20

# Agrega el bloque a la cadena
for i in range(0, num_of_blocks_to_add):
  block_to_add = next_block(previous_block)
  blockchain.append(block_to_add)
  previous_block = block_to_add
  # Le dice a todos sobre este
  print "Bloq #{} ha sido agregado a nuestra cadena de bloques!".format(block_to_add.index)
  print "Hash: {}\n".format(block_to_add.hash)