iCoin update

Author: akshaybahadur21

LICENSE.txt

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+MIT License
+
+Copyright (c) 2017 Akshay Bahadur
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

iCoin.py

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+from flask import Flask
+from flask import request
+import json
+import requests
+import hashlib as hasher
+import datetime as date
+node = Flask(__name__)
+
+class CreateBlock:
+  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.create_hash()
+  
+  def create_hash(self):
+    sha = hasher.sha256()
+    sha.update(str(self.index) + str(self.timestamp) + str(self.data) + str(self.previous_hash))
+    return sha.hexdigest()
+
+
+def create_first_block():
+  return CreateBlock(0, date.datetime.now(), {
+    "proof-of-work": 8831*547,
+    "transactions": None
+  }, "0")
+
+
+miner_address = "frufhi55kefj-akshay-address-ndji45jjg6"
+blockchain = []
+blockchain.append(create_first_block())
+this_nodes_transactions = []
+
+peer_nodes = []
+mining = True
+
+@node.route('/request_transaction', methods=['POST'])
+def transaction():
+  new_request_data = request.get_json()
+  this_nodes_transactions.append(new_request_data)
+  print "Transaction"
+  print this_nodes_transactions
+  print new_request_data
+  print "FROM: {}".format(new_request_data['from'].encode('ascii','replace'))
+  print "TO: {}".format(new_request_data['to'].encode('ascii','replace'))
+  print "AMOUNT: {}\n".format(new_request_data['amount'])
+  return "Transaction successful\n"
+
+@node.route('/blocks', methods=['GET'])
+def get_blocks():
+  chain_send = blockchain
+  blocklist = ""
+  for i in range(len(chain_send)):
+    block = chain_send[i]
+    block_index = str(block.index)
+    block_timestamp = str(block.timestamp)
+    block_data = str(block.data)
+    block_hash = block.hash
+    assembled = json.dumps({
+    "index": block_index,
+    "timestamp": block_timestamp,
+    "data": block_data,
+    "hash": block_hash
+    })
+    if blocklist == "":
+      blocklist = assembled
+    else:
+      blocklist += assembled
+  return blocklist
+
+def find_new_chains():
+  chains = []
+  for node_url in peer_nodes:
+    block = requests.get(node_url + "/blocks").content
+    block = json.loads(block)
+    chains.append(block)
+  return chains
+
+def consensus():
+  chains = find_new_chains()
+  longest_chain = blockchain
+  for chain in chains:
+    if len(longest_chain) < len(chain):
+      longest_chain = chain
+  blockchain = longest_chain
+
+def proof_of_work(last_proof):
+  flag = last_proof + 1
+  proof_of_work_number=8831*547 #choose a combination 2 big prime number so that computational time is more
+  while not (flag % proof_of_work_number == 0 and flag % last_proof == 0):
+    flag += 1
+  return flag
+
+@node.route('/mine', methods = ['GET'])
+def mine():
+  last_block = blockchain[len(blockchain) - 1]
+  last_proof = last_block.data['proof-of-work']
+  proof = proof_of_work(last_proof)
+  this_nodes_transactions.append(
+    { "from": "System", "to": miner_address, "amount": 1 }
+  )
+
+  new_block_data = {
+    "proof-of-work": proof,
+    "transactions": list(this_nodes_transactions)
+  }
+  new_block_index = last_block.index + 1
+  new_block_timestamp = this_timestamp = date.datetime.now()
+  last_block_hash = last_block.hash
+  this_nodes_transactions[:] = []
+  mined_block = CreateBlock(
+    new_block_index,
+    new_block_timestamp,
+    new_block_data,
+    last_block_hash
+  )
+  blockchain.append(mined_block)
+  return json.dumps({
+      "index": new_block_index,
+      "timestamp": str(new_block_timestamp),
+      "data": new_block_data,
+      "hash": last_block_hash
+  }) + "\n"
+
+node.run()
+

mine.PNG

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+## iCoin
+This code explains the working of Crypto-currency.
+
+
+### Code Requirements
+The example code is in Python ([version 2.7](https://www.python.org/download/releases/2.7/) or higher will work). 
+1) import hashlib
+2) import flask
+
+### Description
+
+A cryptocurrency (or crypto currency) is a digital asset designed to work as a medium of exchange using cryptography to secure the transactions and to control the creation of additional units of the currency. Cryptocurrencies are classified as a subset of digital currencies and are also classified as a subset of alternative currencies and virtual currencies.
+
+####Concepts
+
+1) [Proof-of-Work Algorithm](https://en.wikipedia.org/wiki/Proof-of-work_system)
+2) [Concensus Algorithm](https://en.wikipedia.org/wiki/Consensus_(computer_science))
+
+For more information, [see](https://en.wikipedia.org/wiki/Cryptocurrency)
+
+###Steps
+
+1) After you have set up the python code, you need to send a POST request of transferring iCoins to someone.
+
+<img src="https://github.com/akshaybahadur21/iCoin-CryptoCurrency/blob/master/setup.png">
+
+<img src="https://github.com/akshaybahadur21/iCoin-CryptoCurrency/blob/master/post.png">
+
+2) Now mine the block for verification by send a GET request
+
+<img src="https://github.com/akshaybahadur21/iCoin-CryptoCurrency/blob/master/mine.png">
+
+3) You can check all the blocks by sending a get request to '/blocks'
+
+
+### Execution
+To run the code, type `python block_chain.py`
+
+```
+python block_chain.py
+```