sourav11295/Blockchain

1# -*- coding: utf-8 -*-2"""Blockchain.ipynb3 4Automatically generated by Colaboratory.5 6Original file is located at7    https://colab.research.google.com/drive/1wfXS6MTMX2J77EP5X1qFiKQzdo_eh5118"""9 10import datetime11import hashlib12import json13 14class Blockchain:15 16    def __init__(self):17        self.chain = []18        self.create_block(proof=1, previous_hash='0')19    20    def create_block(self, proof, previous_hash):21        block = {'index': len(self.chain) + 1,22                 'timestamp': str(datetime.datetime.now()),23                 'proof': proof,24                 'previous_hash': previous_hash}25        self.chain.append(block)26        return block27    28    def print_previous_block(self):29        return self.chain[-1]30       31    def proof_of_work(self, previous_proof):32        new_proof = 133        check_proof = False34         35        while check_proof is False:36            hash_operation = hashlib.sha256(37                str(new_proof**2 - previous_proof**2).encode()).hexdigest()38            if hash_operation[:5] == '00000':39                check_proof = True40            else:41                new_proof += 142                 43        return new_proof44 45    def hash(self, block):46        encoded_block = json.dumps(block, sort_keys=True).encode()47        return hashlib.sha256(encoded_block).hexdigest()48 49    def chain_valid(self, chain):50        previous_block = chain[0]51        block_index = 152         53        while block_index < len(chain):54            block = chain[block_index]55            if block['previous_hash'] != self.hash(previous_block):56                return False57               58            previous_proof = previous_block['proof']59            proof = block['proof']60            hash_operation = hashlib.sha256(61                str(proof**2 - previous_proof**2).encode()).hexdigest()62             63            if hash_operation[:5] != '00000':64                return False65            previous_block = block66            block_index += 167         68        return True69 70def create_chain():71  global blockchain72  blockchain = Blockchain()73  return "Chain Instantiated"74 75def del_chain():76  global blockchain77  del blockchain78  return "Chain Deleted"79 80def mine_block():81    previous_block = blockchain.print_previous_block()82    previous_proof = previous_block['proof']83    proof = blockchain.proof_of_work(previous_proof)84    previous_hash = blockchain.hash(previous_block)85    block = blockchain.create_block(proof, previous_hash)86     87    response = {'message': 'A block is MINED',88                'index': block['index'],89                'timestamp': block['timestamp'],90                'proof': block['proof'],91                'previous_hash': block['previous_hash']}92     93    return response94 95def hack_block(index,value):96  index=int(index.split(" ")[1])-197  blockchain.chain[index]['proof']=value98  return f"block modified at index:{index+1}"99 100def display_chain():101    try:102      response = {'chain': blockchain.chain,'length': len(blockchain.chain)}103      104    except:105      response = "No chain found"106    return response107 108def valid():109    valid = blockchain.chain_valid(blockchain.chain)110     111    if valid:112        response = {'message': 'The Blockchain is valid.'}113    else:114        response = {'message': 'The Blockchain is not valid.'}115    return response116 117import gradio as gr118 119with gr.Blocks(title='Blockchain Simulator') as demo:120    gr.Image(value="./Blockchain.jpg",show_label=False,shape=(1500,300))121    with gr.Row():122        with gr.Column(scale=3):123            display = gr.Textbox(label="Blockchain Output",lines=5)124            dblock = gr.Button("Display/Refresh Blockchain")125        with gr.Column(scale=2):126            cblock = gr.Button("Instantiate Blockchain")127            mblock = gr.Button("Mine a Block")128            vblock = gr.Button("Validate Blockchain")129            delblock = gr.Button("Delete Blockchain") 130        with gr.Column(scale=2):131            index = gr.Radio(choices=["index 1", "index 2", "index 3"],label="Choose an Index to hack")132            value = gr.Textbox(label="New Value", placeholder = "Enter a Value")133            hblock = gr.Button("Hack a Block")134    dblock.click(fn=display_chain, inputs=[], outputs=[display],show_progress=True)135    cblock.click(fn=create_chain, inputs=[], outputs=[display],show_progress=True)136    mblock.click(fn=mine_block, inputs=[], outputs=[display],show_progress=True)137    vblock.click(fn=valid, inputs=[], outputs=[display],show_progress=True)138    delblock.click(fn=del_chain, inputs=[], outputs=[display],show_progress=True)139    hblock.click(fn=hack_block, inputs=[index,value], outputs=[display],show_progress=True)140 141demo.launch()