Blockchain Simulation using python

Implemented in the following Script

Author: isidharthrai

[tampered]addBlock.py

@@ -0,0 +1,42 @@
+import hashlib as hasher
+import datetime as date
+
+#importing the block
+from block import Block
+
+#importing the chain
+import jupiter_block as jb
+import pluto_block as pb
+import neptune_block as nb
+
+
+# Generate all later blocks in the blockchain
+def next_block(last_block):
+  this_index = last_block.index + 1
+  this_timestamp = date.datetime.now()
+  this_data = last_block.data
+  this_hash = last_block.hash
+  return Block(this_index, this_timestamp, this_data, this_hash)
+
+# Create the blockchain and add the genesis block
+blockchain = [jb.create_jupiter_block(), pb.create_pluto_block(), nb.create_neptune_block()]
+
+# How many blocks should we add to the chain
+# after the genesis block
+num_of_blocks_to_add = 1
+
+# Add blocks to the chain
+for i in range (len(blockchain)):
+    previous_block = blockchain[i]
+    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
+        # Tell everyone about it!
+        print("Block #{} added ".format(block_to_add.data))
+        print("Hash: {}".format(block_to_add.hash))
+        print("TimeStamp: {}".format(block_to_add.timestamp))
+        print("Previous hash: {} \n".format(block_to_add.previous_hash))
+
+
+

addBlock.py

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+import hashlib as hasher
+import datetime as date
+
+#importing the block
+from block import Block
+
+#importing the chain
+import jupiter_block as jb
+import pluto_block as pb
+import neptune_block as nb
+
+
+# Generate all later blocks in the blockchain
+def next_block(last_block):
+  this_index = last_block.index + 1
+  this_timestamp = date.datetime.now()
+  this_data = last_block.data
+  this_hash = last_block.hash
+  return Block(this_index, this_timestamp, this_data, this_hash)
+
+# Create the blockchain and add the genesis block
+blockchain = [jb.create_jupiter_block()]
+previous_block = blockchain[0]
+
+# How many blocks should we add to the chain
+# after the genesis block
+num_of_blocks_to_add = 20
+
+# Add blocks to the chain
+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
+  # Tell everyone about it
+  print("Block #{} added ".format(block_to_add.data))
+  print("Hash: {}".format(block_to_add.hash))
+  print("TimeStamp: {}".format(block_to_add.timestamp))
+  print("Previous hash: {} \n".format(block_to_add.previous_hash))
+
+
+

block.py

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+import hashlib as hasher
+import datetime as date
+
+# Define what a block is
+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).encode('utf-8') + str(self.timestamp).encode('utf-8') + str(self.data).encode('utf-8') + str(self.previous_hash).encode('utf-8'))
+    return sha.hexdigest()

jupiter_block.py

@@ -0,0 +1,7 @@
+import datetime as date
+from block import Block
+
+def create_jupiter_block():
+  # Manually construct a block with
+  # index zero and arbitrary previous hash
+  return Block(0, date.datetime.now(), "Jupiter Block", "0")

neptune_block.py

@@ -0,0 +1,7 @@
+import datetime as date
+from block import Block
+
+def create_neptune_block():
+  # Manually construct a block with
+  # index zero and arbitrary previous hash
+  return Block(2, date.datetime.now(), "Neptune Block", "2")

pluto_block.py

@@ -0,0 +1,7 @@
+import datetime as date
+from block import Block
+
+def create_pluto_block():
+  # Manually construct a block with
+  # index zero and arbitrary previous hash
+  return Block(1, date.datetime.now(), "Pluto Block", "1")

validate_blockchain.py

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+import hashlib
+s = hashlib.sha256()
+
+from block import Block
+import addBlock as add
+
+def validate_blockchain(blockchain):
+
+    for i in range (1,len(blockchain)):
+        current_block = blockchain[i]
+        previous_block = blockchain[i-1]
+
+        #current hash and calulated hash
+        if ( current_block.hash != current_block.hash_block()):
+            print ("Invalid Stage 1 error for Block {}".format(current_block.index))
+            return False
+
+        #previous hash validation
+        if ( current_block.previous_hash != previous_block.hash):
+            print ("Invalid Stage 2 error for Block {}".format(current_block.index))
+            return False
+    print("Valid at all stages")
+    return True
+
+validate_blockchain(add.blockchain)