130 lines
3.4 KiB
Text
130 lines
3.4 KiB
Text
{
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"cells": [
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{
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"cell_type": "code",
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"execution_count": 31,
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"metadata": {},
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"outputs": [],
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"source": [
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"import os\n",
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"\n",
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"import hashlib\n",
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"import nacl.signing\n",
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"from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes\n",
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"from cryptography.hazmat.backends import default_backend"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 7,
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"metadata": {},
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"outputs": [],
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"source": [
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"sign_key = nacl.signing.SigningKey.generate()"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 44,
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"metadata": {},
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"outputs": [],
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"source": [
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"make_action_string = lambda group, index: f'reset idx={index:08x} g={group}'.encode()\n",
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"def generate_presig(group, index):\n",
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" action_string = make_action_string(group, index)\n",
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" sig = sign_key.sign(action_string)[:64] # cut off original message\n",
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" \n",
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" key = os.urandom(16)\n",
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" \n",
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" cipher = Cipher(algorithms.AES(key), modes.CTR(b'\\0' * 16), backend=default_backend())\n",
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" enc = cipher.encryptor()\n",
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" ciphtertext = enc.update(sig)\n",
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" assert len(enc.finalize()) == 0\n",
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" \n",
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" return key, ciphtertext\n",
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"\n",
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"presigs = { group: [ generate_presig(group, index) for index in range(64) ] for group in ['all', 'v=foo', 's=bar', 'l=somewhere'] }"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 46,
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"metadata": {},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"(b'\\x9f\\n\\x8e\\xc9\\x1d\\xaf*\\xac\\x9e\\x1as\\xe8\\xf8\\xe6\\xe9z',\n",
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" b'{\\xd8\\xb4\\xaf\\xb4PK1%*`\\\\\\x8e\\x93;\\x82\\xeaF\\x99\\xe0\\xbfB\\xf1\\x9d\\xae\\x02|\\xae\\\\?\\x97\\xb3\\xa5j.Y\\x83\\xddg\\x7f\\x06\\xd2\\xa47^\\xf3\\xdd\\x08n3\\x90\\x84~\\x96,tO#\\x8e$\\xdc\\xa2\\x1a\\r')"
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]
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},
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"execution_count": 46,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"presigs['all'][0]"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 69,
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"metadata": {},
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"outputs": [],
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"source": [
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"def validate_presig(group, index, key, presig, verify_key=sign_key.verify_key):\n",
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" \"\"\" Will raise an error for invalid signature or group/index \"\"\"\n",
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" action_string = make_action_string(group, index)\n",
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" \n",
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" cipher = Cipher(algorithms.AES(key), modes.CTR(b'\\0' * 16), backend=default_backend())\n",
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" dec = cipher.decryptor()\n",
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" plaintext = dec.update(presig)\n",
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" assert len(dec.finalize()) == 0\n",
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" \n",
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" return verify_key.verify(plaintext + action_string) == action_string"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 70,
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"metadata": {},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"True"
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]
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},
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"execution_count": 70,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"validate_presig('all', 0, *presigs['all'][0])"
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]
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "labenv",
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"language": "python",
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"name": "labenv"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 3
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.8.2"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 4
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}
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