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Added invalidation checks.
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Petteri Nevavuori committed Apr 11, 2018
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Showing 1 changed file with 173 additions and 27 deletions.
200 changes: 173 additions & 27 deletions blockchain/Building a General Purpose Blockchain.ipynb
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},
"source": [
"<h1>Table of Contents<span class=\"tocSkip\"></span></h1>\n",
"<div class=\"toc\"><ul class=\"toc-item\"><li><span><a href=\"#1.-Building-the-Blockhain\" data-toc-modified-id=\"1.-Building-the-Blockhain-1\">1. Building the Blockhain</a></span></li><li><span><a href=\"#2.-Creating-the-Web-App\" data-toc-modified-id=\"2.-Creating-the-Web-App-2\">2. Creating the Web App</a></span><ul class=\"toc-item\"><li><span><a href=\"#2.1-Testing-the-Blockchain-App\" data-toc-modified-id=\"2.1-Testing-the-Blockchain-App-2.1\">2.1 Testing the Blockchain App</a></span></li></ul></li><li><span><a href=\"#3.-Mining--Blocks\" data-toc-modified-id=\"3.-Mining--Blocks-3\">3. Mining Blocks</a></span></li></ul></div>"
"<div class=\"toc\"><ul class=\"toc-item\"><li><span><a href=\"#1.-Building-the-Blockhain\" data-toc-modified-id=\"1.-Building-the-Blockhain-1\">1. Building the Blockhain</a></span></li><li><span><a href=\"#2.-Creating-the-Web-App\" data-toc-modified-id=\"2.-Creating-the-Web-App-2\">2. Creating the Web App</a></span><ul class=\"toc-item\"><li><span><a href=\"#2.1-Testing-the-Blockchain-App\" data-toc-modified-id=\"2.1-Testing-the-Blockchain-App-2.1\">2.1 Testing the Blockchain App</a></span></li></ul></li><li><span><a href=\"#3.-Mining--Blocks\" data-toc-modified-id=\"3.-Mining--Blocks-3\">3. Mining Blocks</a></span><ul class=\"toc-item\"><li><span><a href=\"#3.1-Testing-the-Chain-Validity\" data-toc-modified-id=\"3.1-Testing-the-Chain-Validity-3.1\">3.1 Testing the Chain Validity</a></span></li></ul></li></ul></div>"
]
},
{
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" next_proof = chain[i]['proof']\n",
"\n",
" if self.hash_proof(previous_proof, next_proof)[:4] != '0000':\n",
" \n",
" return False\n",
"\n",
" return True"
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"name": "stderr",
"output_type": "stream",
"text": [
"127.0.0.1 - - [11/Apr/2018 09:49:58] \"POST /blocks HTTP/1.1\" 200 -\n"
"127.0.0.1 - - [11/Apr/2018 10:00:41] \"POST /blocks HTTP/1.1\" 200 -\n"
]
},
{
Expand All @@ -289,9 +290,9 @@
"{\n",
" \"block\": {\n",
" \"index\": 1,\n",
" \"previous_hash\": \"5cc26226686b36400b40fe89530ff4b0174d4e3f73f609af0efc8bc85e6f08cf\",\n",
" \"previous_hash\": \"f198e29bb5e45e308d25579fc8f52a36fea66ba22ca61d18e654125c04116340\",\n",
" \"proof\": 533,\n",
" \"timestamp\": \"2018-04-11 09:49:58.119854\"\n",
" \"timestamp\": \"2018-04-11 10:00:41.379830\"\n",
" },\n",
" \"message\": \"Congratulations, you just mined a Block!\"\n",
"}\n"
Expand All @@ -301,7 +302,7 @@
"name": "stderr",
"output_type": "stream",
"text": [
"127.0.0.1 - - [11/Apr/2018 09:49:59] \"GET /blocks HTTP/1.1\" 200 -\n"
"127.0.0.1 - - [11/Apr/2018 10:00:42] \"GET /blocks HTTP/1.1\" 200 -\n"
]
},
{
Expand All @@ -314,13 +315,13 @@
" \"index\": 0,\n",
" \"previous_hash\": \"0\",\n",
" \"proof\": 1,\n",
" \"timestamp\": \"2018-04-11 09:49:57.088693\"\n",
" \"timestamp\": \"2018-04-11 10:00:40.317214\"\n",
" },\n",
" {\n",
" \"index\": 1,\n",
" \"previous_hash\": \"5cc26226686b36400b40fe89530ff4b0174d4e3f73f609af0efc8bc85e6f08cf\",\n",
" \"previous_hash\": \"f198e29bb5e45e308d25579fc8f52a36fea66ba22ca61d18e654125c04116340\",\n",
" \"proof\": 533,\n",
" \"timestamp\": \"2018-04-11 09:49:58.119854\"\n",
" \"timestamp\": \"2018-04-11 10:00:41.379830\"\n",
" }\n",
" ],\n",
" \"length\": 2,\n",
Expand All @@ -332,7 +333,7 @@
"name": "stderr",
"output_type": "stream",
"text": [
"127.0.0.1 - - [11/Apr/2018 09:50:00] \"GET /shutdown HTTP/1.1\" 200 -\n"
"127.0.0.1 - - [11/Apr/2018 10:00:43] \"GET /shutdown HTTP/1.1\" 200 -\n"
]
}
],
Expand Down Expand Up @@ -374,7 +375,7 @@
"output_type": "stream",
"text": [
" * Running on http://localhost:5000/ (Press CTRL+C to quit)\n",
"127.0.0.1 - - [11/Apr/2018 09:50:01] \"POST /blocks HTTP/1.1\" 200 -\n"
"127.0.0.1 - - [11/Apr/2018 10:00:44] \"POST /blocks HTTP/1.1\" 200 -\n"
]
},
{
Expand All @@ -388,7 +389,7 @@
"name": "stderr",
"output_type": "stream",
"text": [
"127.0.0.1 - - [11/Apr/2018 09:50:02] \"POST /blocks HTTP/1.1\" 200 -\n"
"127.0.0.1 - - [11/Apr/2018 10:00:45] \"POST /blocks HTTP/1.1\" 200 -\n"
]
},
{
Expand All @@ -402,7 +403,7 @@
"name": "stderr",
"output_type": "stream",
"text": [
"127.0.0.1 - - [11/Apr/2018 09:50:03] \"POST /blocks HTTP/1.1\" 200 -\n"
"127.0.0.1 - - [11/Apr/2018 10:00:46] \"POST /blocks HTTP/1.1\" 200 -\n"
]
},
{
Expand All @@ -416,7 +417,7 @@
"name": "stderr",
"output_type": "stream",
"text": [
"127.0.0.1 - - [11/Apr/2018 09:50:04] \"POST /blocks HTTP/1.1\" 200 -\n"
"127.0.0.1 - - [11/Apr/2018 10:00:48] \"POST /blocks HTTP/1.1\" 200 -\n"
]
},
{
Expand All @@ -430,7 +431,7 @@
"name": "stderr",
"output_type": "stream",
"text": [
"127.0.0.1 - - [11/Apr/2018 09:50:05] \"GET /blocks HTTP/1.1\" 200 -\n"
"127.0.0.1 - - [11/Apr/2018 10:00:49] \"GET /blocks HTTP/1.1\" 200 -\n"
]
},
{
Expand All @@ -443,37 +444,37 @@
" \"index\": 0,\n",
" \"previous_hash\": \"0\",\n",
" \"proof\": 1,\n",
" \"timestamp\": \"2018-04-11 09:49:57.088693\"\n",
" \"timestamp\": \"2018-04-11 10:00:40.317214\"\n",
" },\n",
" {\n",
" \"index\": 1,\n",
" \"previous_hash\": \"5cc26226686b36400b40fe89530ff4b0174d4e3f73f609af0efc8bc85e6f08cf\",\n",
" \"previous_hash\": \"f198e29bb5e45e308d25579fc8f52a36fea66ba22ca61d18e654125c04116340\",\n",
" \"proof\": 533,\n",
" \"timestamp\": \"2018-04-11 09:49:58.119854\"\n",
" \"timestamp\": \"2018-04-11 10:00:41.379830\"\n",
" },\n",
" {\n",
" \"index\": 2,\n",
" \"previous_hash\": \"0dff44d24efffd7139e45d3248f95ea5ca738a0b0fcbc910841eef62bdf6639b\",\n",
" \"previous_hash\": \"8e0369ebcfe420065d5b3394c2ece9b06185757005b305a2d3e7277055281860\",\n",
" \"proof\": 45293,\n",
" \"timestamp\": \"2018-04-11 09:50:01.290186\"\n",
" \"timestamp\": \"2018-04-11 10:00:44.678168\"\n",
" },\n",
" {\n",
" \"index\": 3,\n",
" \"previous_hash\": \"632dd0c50d9db200bdc44cada8b33a4af68b69eda3e88d8e1a8c74fb31a619b5\",\n",
" \"previous_hash\": \"df340007864a5fbd2a2465a9d2ac25f183416b5564a61fda2e87eb44d1ca18fb\",\n",
" \"proof\": 21391,\n",
" \"timestamp\": \"2018-04-11 09:50:02.379049\"\n",
" \"timestamp\": \"2018-04-11 10:00:45.831691\"\n",
" },\n",
" {\n",
" \"index\": 4,\n",
" \"previous_hash\": \"299404399564af95463860d39b49ffdaa4f2d183dc5d8f625dedff45e22464ff\",\n",
" \"previous_hash\": \"04f6299127b6fb0fb659e5b0ad54b3e2fa5d43739ae13e72a31da9ec04c7a18a\",\n",
" \"proof\": 8018,\n",
" \"timestamp\": \"2018-04-11 09:50:03.411990\"\n",
" \"timestamp\": \"2018-04-11 10:00:46.882162\"\n",
" },\n",
" {\n",
" \"index\": 5,\n",
" \"previous_hash\": \"1fdae0359c52d943575befbfb55e4c4a19ef5ef267bbbd14903b1e16651ffc76\",\n",
" \"previous_hash\": \"003a0b87af5ad8d94070f7632b12b90ff18c4271fd7e2eae395be7b02aeaa50b\",\n",
" \"proof\": 48191,\n",
" \"timestamp\": \"2018-04-11 09:50:04.590271\"\n",
" \"timestamp\": \"2018-04-11 10:00:48.076540\"\n",
" }\n",
" ],\n",
" \"length\": 6,\n",
Expand All @@ -485,7 +486,7 @@
"name": "stderr",
"output_type": "stream",
"text": [
"127.0.0.1 - - [11/Apr/2018 09:50:06] \"GET /shutdown HTTP/1.1\" 200 -\n"
"127.0.0.1 - - [11/Apr/2018 10:00:50] \"GET /shutdown HTTP/1.1\" 200 -\n"
]
}
],
Expand All @@ -505,8 +506,153 @@
"cell_type": "markdown",
"metadata": {},
"source": [
"If you compare the first two Blocks with the test run you can see that the hashes and proofs match. This intended, as already stated.\n",
"If you compare the first two Blocks with the test run you can see that the hashes and proofs match. This intended, as already stated."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### 3.1 Testing the Chain Validity\n",
"\n",
"We also want to see if changing the proof mid-chain breaks the chain. For this we must access the initialized ``Blockchain`` directly as the miniserver doesn't have a method for altering the chain - which is a wise starting point!"
]
},
{
"cell_type": "code",
"execution_count": 6,
"metadata": {},
"outputs": [
{
"name": "stderr",
"output_type": "stream",
"text": [
" * Running on http://localhost:5000/ (Press CTRL+C to quit)\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"text": [
"Proofs: Original=21391, Forged=21391\n"
]
},
{
"name": "stderr",
"output_type": "stream",
"text": [
"127.0.0.1 - - [11/Apr/2018 10:00:51] \"GET /blocks HTTP/1.1\" 500 -\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"text": [
"{\n",
" \"blockchain\": [\n",
" {\n",
" \"index\": 0,\n",
" \"previous_hash\": \"0\",\n",
" \"proof\": 1,\n",
" \"timestamp\": \"2018-04-11 10:00:40.317214\"\n",
" },\n",
" {\n",
" \"index\": 1,\n",
" \"previous_hash\": \"f198e29bb5e45e308d25579fc8f52a36fea66ba22ca61d18e654125c04116340\",\n",
" \"proof\": 12345,\n",
" \"timestamp\": \"2018-04-11 10:00:41.379830\"\n",
" },\n",
" {\n",
" \"index\": 2,\n",
" \"previous_hash\": \"8e0369ebcfe420065d5b3394c2ece9b06185757005b305a2d3e7277055281860\",\n",
" \"proof\": 45293,\n",
" \"timestamp\": \"2018-04-11 10:00:44.678168\"\n",
" },\n",
" {\n",
" \"index\": 3,\n",
" \"previous_hash\": \"df340007864a5fbd2a2465a9d2ac25f183416b5564a61fda2e87eb44d1ca18fb\",\n",
" \"proof\": 21391,\n",
" \"timestamp\": \"2018-04-11 10:00:45.831691\"\n",
" },\n",
" {\n",
" \"index\": 4,\n",
" \"previous_hash\": \"04f6299127b6fb0fb659e5b0ad54b3e2fa5d43739ae13e72a31da9ec04c7a18a\",\n",
" \"proof\": 8018,\n",
" \"timestamp\": \"2018-04-11 10:00:46.882162\"\n",
" },\n",
" {\n",
" \"index\": 5,\n",
" \"previous_hash\": \"003a0b87af5ad8d94070f7632b12b90ff18c4271fd7e2eae395be7b02aeaa50b\",\n",
" \"proof\": 48191,\n",
" \"timestamp\": \"2018-04-11 10:00:48.076540\"\n",
" }\n",
" ],\n",
" \"length\": 6,\n",
" \"message\": \"Chain is not valid!\"\n",
"}\n"
]
},
{
"name": "stderr",
"output_type": "stream",
"text": [
"127.0.0.1 - - [11/Apr/2018 10:00:52] \"GET /shutdown HTTP/1.1\" 200 -\n"
]
}
],
"source": [
"original = blockchain.chain[3]['proof']\n",
"blockchain.chain[1]['proof'] = 12345\n",
"print('Proofs: Original={}, Forged={}'.format(original,blockchain.chain[3]['proof']))\n",
"\n",
"with BlockchainApp() as blockchain_app:\n",
" \n",
" response = blockchain_app.get_blockchain()\n",
" print(json.dumps(response.json(), indent=2))\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"And so we indeed have invalidated the chain! Let's yet see what the hash should've been for Block in index ``2``, as it would be the one invalidated by the forgery."
]
},
{
"cell_type": "code",
"execution_count": 13,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Hashes: \n",
"\tOriginal =\t8e0369ebcfe420065d5b3394c2ece9b06185757005b305a2d3e7277055281860\n",
"\tForged =\tb3e1a78ae4b5cd947a6690f4a5ee9b3a71a13a2df00d77cbc4c904c9b2ac2deb\n"
]
}
],
"source": [
"proof_1 = blockchain.chain[1]['proof']\n",
"proof_2 = blockchain.chain[2]['proof']\n",
"\n",
"forged_hash = blockchain.hash_proof(proof_1, proof_2)\n",
"\n",
"print(\"Hashes: \\n\\tOriginal =\\t{}\\n\\tForged =\\t{}\".format(blockchain.chain[2]['previous_hash'],forged_hash))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"What a difference. "
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"**This concludes the building and mining of a general purpose centralized Blockchain.**"
]
}
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