blockchain-poc.ipynb

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   "id": "94e0ada1-2cc2-4948-a4a7-357207690113",
   "metadata": {},
   "outputs": [],
   "source": [
    "import hashlib\n",
    "import time\n",
    "import os"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 55,
   "id": "4e1a3136-9aae-45ad-9018-20fdf2425128",
   "metadata": {},
   "outputs": [],
   "source": [
    "NUMBER_OF_ZEROES = 5\n",
    "PREFIX = '0' * NUMBER_OF_ZEROES"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 56,
   "id": "7f0614d2-be5a-4684-9aa4-762233e2dd5a",
   "metadata": {},
   "outputs": [],
   "source": [
    "class Block():\n",
    "    def is_hash_ok(self, hash):\n",
    "        return hash.startswith( PREFIX )\n",
    "    \n",
    "    def generate_hash(self):\n",
    "        temporal_hash = ''\n",
    "        temporal_nonce = 0\n",
    "        \n",
    "        block_to_compare = lambda block : \"{0}{1}{2}{3}\".format( block.previous_block_hash, block.data, str(block.time), str(block.height) )\n",
    "        \n",
    "        prefix = block_to_compare(self)\n",
    "        \n",
    "        while not self.is_hash_ok( temporal_hash ):\n",
    "            temporal_hash = hashlib.sha256( (prefix + str(temporal_nonce)).encode()).hexdigest()\n",
    "            temporal_nonce += 1\n",
    "        \n",
    "        self.nonce = temporal_nonce - 1\n",
    "        self.hash = temporal_hash\n",
    "    \n",
    "    def __str__(self):\n",
    "        text = '''----------\n",
    "        previous block hash {0}\n",
    "        data                {1}\n",
    "        time                {2}, {3}\n",
    "        height              {4}\n",
    "        nonce               {5}\n",
    "        hash                {6}'''\n",
    "    \n",
    "        #time.strftime('%Y/%m/%d %H:%M:%S', time.localtime(self.time))\n",
    "        return text.format( self.previous_block_hash, self.data, self.time, self.time, self.height, self.nonce, self.hash )  \n",
    "   \n",
    "    def __init__(self, data, previous_block):\n",
    "        if previous_block == None: # genesis block\n",
    "            self.previous_block_hash = '0' * 64\n",
    "            self.height = 0\n",
    "        else: # regular block\n",
    "            self.previous_block_hash = previous_block.hash\n",
    "            self.height = previous_block.height + 1\n",
    "\n",
    "        self.time = time.time_ns()        \n",
    "        self.data = data\n",
    "        \n",
    "        self.generate_hash()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 57,
   "id": "d07e5970-a297-4b50-82a9-a432b27e5cb1",
   "metadata": {},
   "outputs": [],
   "source": [
    "class BlockChain():\n",
    "    def __init__(self, name='test0'):\n",
    "        self.chain = []\n",
    "        \n",
    "        self.chain.append( Block('Genesis block for ' + name, None) )\n",
    "    \n",
    "    def __len__(self):\n",
    "        return len(self.chain)\n",
    "\n",
    "    def __str__(self):\n",
    "        return os.linesep.join( [block.__str__() for block in self.chain] )\n",
    "\n",
    "    def get_total_nonce(self):\n",
    "        return sum([block.nonce for block in self.chain])\n",
    "            \n",
    "    def add_block(self, data):\n",
    "        self.chain.append( Block(data, self.chain[-1] ) )\n",
    "    \n",
    "    def get_last_block(self):\n",
    "        return self.chain[-1]\n",
    "\n",
    "    def get_genesis_block(self):\n",
    "        return self.chain[0]   "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 58,
   "id": "1aa69f38-f745-4884-9d5d-fdd8cca78096",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "----------\n",
      "        previous block hash 0000000000000000000000000000000000000000000000000000000000000000\n",
      "        data                Genesis block for test0\n",
      "        time                1662408926071676600, 1662408926071676600\n",
      "        height              0\n",
      "        nonce               1623651\n",
      "        hash                00000a5e54a3a41f9599ae0ecea3d9364e95bfee2df619a5b8f4b9faab86b6f4\n",
      "----------\n",
      "        previous block hash 00000a5e54a3a41f9599ae0ecea3d9364e95bfee2df619a5b8f4b9faab86b6f4\n",
      "        data                I am data number 0\n",
      "        time                1662408928614430400, 1662408928614430400\n",
      "        height              1\n",
      "        nonce               408633\n",
      "        hash                000007c768aed17ddccf062186e19e35c453077989f2ea4ab7d715a528107d5d\n",
      "----------\n",
      "        previous block hash 000007c768aed17ddccf062186e19e35c453077989f2ea4ab7d715a528107d5d\n",
      "        data                I am data number 1\n",
      "        time                1662408929273997300, 1662408929273997300\n",
      "        height              2\n",
      "        nonce               425933\n",
      "        hash                0000090da6fc7d27551cfc5776dd207002b7d1dc210b39acbac90b6a0994ca04\n",
      "----------\n",
      "        previous block hash 0000090da6fc7d27551cfc5776dd207002b7d1dc210b39acbac90b6a0994ca04\n",
      "        data                I am data number 2\n",
      "        time                1662408929969818900, 1662408929969818900\n",
      "        height              3\n",
      "        nonce               1643889\n",
      "        hash                00000a1aa200aa24c0b89ac363cf786649fdbdc3262241ff4ccf1729746b55b0\n",
      "----------\n",
      "        previous block hash 00000a1aa200aa24c0b89ac363cf786649fdbdc3262241ff4ccf1729746b55b0\n",
      "        data                I am data number 3\n",
      "        time                1662408932471900300, 1662408932471900300\n",
      "        height              4\n",
      "        nonce               1271906\n",
      "        hash                0000083355807b33ea073b11546dbcaf9faaf5ffe5f94a9ec7a479563a9e39a0\n",
      "----------\n",
      "        previous block hash 0000083355807b33ea073b11546dbcaf9faaf5ffe5f94a9ec7a479563a9e39a0\n",
      "        data                I am data number 4\n",
      "        time                1662408934378018100, 1662408934378018100\n",
      "        height              5\n",
      "        nonce               4241179\n",
      "        hash                00000a4c58633d4a44ae8e33956cde24b5445bda4733ebae4a5f3e5f7204a5d8\n",
      "----------\n",
      "        previous block hash 00000a4c58633d4a44ae8e33956cde24b5445bda4733ebae4a5f3e5f7204a5d8\n",
      "        data                I am data number 5\n",
      "        time                1662408940716870200, 1662408940716870200\n",
      "        height              6\n",
      "        nonce               383138\n",
      "        hash                0000013bfa24096128e079b3129dc59c6218d1a1e1a2cf411867327788ee1117\n",
      "----------\n",
      "        previous block hash 0000013bfa24096128e079b3129dc59c6218d1a1e1a2cf411867327788ee1117\n",
      "        data                I am data number 6\n",
      "        time                1662408941300641700, 1662408941300641700\n",
      "        height              7\n",
      "        nonce               1880915\n",
      "        hash                0000090f29706f350bd6df3a5af8d79d5ec2f6d8cb5434b494db9b2f742dd7ad\n",
      "----------\n",
      "        previous block hash 0000090f29706f350bd6df3a5af8d79d5ec2f6d8cb5434b494db9b2f742dd7ad\n",
      "        data                I am data number 7\n",
      "        time                1662408944355211700, 1662408944355211700\n",
      "        height              8\n",
      "        nonce               952744\n",
      "        hash                00000b49e29e916c6e59f0c032019791137cfe2e3d84506ec12daa8f9192ec55\n",
      "----------\n",
      "        previous block hash 00000b49e29e916c6e59f0c032019791137cfe2e3d84506ec12daa8f9192ec55\n",
      "        data                I am data number 8\n",
      "        time                1662408945819825600, 1662408945819825600\n",
      "        height              9\n",
      "        nonce               469083\n",
      "        hash                00000d26d5d94eef0f0a5c10fa9c18a0dd76273e1651552ba183491d82be6208\n",
      "----------\n",
      "        previous block hash 00000d26d5d94eef0f0a5c10fa9c18a0dd76273e1651552ba183491d82be6208\n",
      "        data                I am data number 9\n",
      "        time                1662408946551314900, 1662408946551314900\n",
      "        height              10\n",
      "        nonce               163462\n",
      "        hash                00000a54d7f9b518057382621723d404e7009fbe70d4a199f09413c52f00a4b9\n",
      "Total nodes, 11\n",
      "Total nonce, 13464533\n"
     ]
    }
   ],
   "source": [
    "blockChain = BlockChain()\n",
    "\n",
    "total_nodes_to_calculate = 10\n",
    "\n",
    "print( blockChain.get_genesis_block() )\n",
    "\n",
    "for i in range(total_nodes_to_calculate):    \n",
    "    blockChain.add_block('I am data number ' + str(i))\n",
    "    print( blockChain.get_last_block() )\n",
    "\n",
    "print( 'Total nodes, {0}'.format( len(blockChain) ) )\n",
    "print( 'Total nonce, {0}'.format( blockChain.get_total_nonce() ) )\n",
    "    \n",
    "#print( blockChain )"
   ]
  }
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